DE102022103279A1 - Calibration element, use of such a calibration element, and method and system - Google Patents

Abstract

The present invention relates to a calibration element for calibrating a laser system, a use of such a calibration element and a method for calibrating a laser system and a laser system.

Description

The present invention relates to a calibration element for calibrating a laser system, use of such a calibration element and a method for calibrating a laser system and a laser system.

State of the art

Laser systems, such as laser scanning systems, must be calibrated during commissioning to ensure proper beam guidance. For example, the mechanical movement of the deflection mirrors within such a system must be matched to the optical properties of the lens used. Further tuning may be necessary if the laser system consists of multiple scanner heads. Even after individual components of the system have been readjusted or replaced, a new calibration is regularly necessary.

For this purpose, a test pattern is often introduced into a "test wafer" using the laser of the laser system. The "test wafer" used for this is e.g. a glass wafer with a thin chrome layer. The pattern generated in this way is compared with a reference pattern. Correction values can then be determined from the deviations between the two patterns, with which the laser system can be calibrated. Typically, the power of the laser is reduced during the calibration process in order to be able to remove the coating in a controlled manner in order to obtain a precise test pattern in this way.

However, the characteristics of the laser source are different for different radiation powers. This difference in characteristics can lead to undesirable tolerances when the laser power during calibration and during productive use are different.

It is therefore the object of the present invention to specify means with which the disadvantages of the prior art can be overcome and which enable a laser system to be reliably calibrated even with relatively high nominal powers.

Description of the invention

The object is achieved by the invention according to a first aspect in that a calibration element for calibrating at least one laser system that has at least one high-power laser radiation source that has a radiation power of 100 W or more at at least one main radiation wavelength,
wherein the calibration element has a substrate with two main sides and at least one coating applied at least in regions on at least one of the main sides,
wherein the coating has at least one interaction area,
wherein radiation emitted by the high-power laser radiation source can be dissipated in the interaction area and wherein the calibration element is set up such that only a fraction of an incident radiation emitted by the high-power laser radiation source and incident on a surface of the calibration element is dissipated in the interaction area, at least partially by (a ) a proportion of the incident radiation supplied to the interaction area by means of a dielectric mirror comprised by the calibration element and/or (b) an interaction cross section of the interaction area with respect to the incident radiation by means of a matrix provided within the interaction area and/or a metallic mirror can be adjusted in each case is proposed .

The invention is thus based on the surprising finding that a laser system can be calibrated even with comparatively high output laser powers by replacing the part of the incident radiation that is effective for modifying the coating of the calibration element with suitable ones, and in particular those exhibited by the calibration element or its parts , Adjustment means can be set to an adjusted value.

As a result, the laser system can be operated at the normal output power for its operational operation during the calibration. However, only a portion of the incident radiation that can be adjusted by the adjustment means is responsible for writing the test pattern into the calibration element, for example by ablating the coating. The radiation dissipated in the interaction area can therefore be adjusted, in particular reduced.

In other words, the entire incident radiation is no longer used to generate the test pattern, such as in particular by removing the coating, but rather a proportion of it that has been reduced by the matching means or means.

Thus, in comparison to conventional calibration elements, a clearly defined pattern can be written into the calibration element even at high laser intensities. As a result, the pattern can be read out much more reliably and more precise calibration data can be generated. With an appropriately calibrated laser system, significantly better work results can therefore be achieved.

Above all, however, the laser system can also be calibrated at the nominal power that is also set or adjustable in productive use for the laser source. As a result, using the proposed calibration element, calibration data for the laser system can be obtained for values of a parameter set (including the laser power) of the system that are also selected in productive use.

The adaptation means proposed according to the invention, in particular in the form of a dielectric mirror, a metallic mirror and/or a matrix provided within the interaction area, can be produced particularly simply and reliably and at the same time inexpensively. At the same time, these adjustment means can advantageously be adjusted very well both with regard to the main emission wavelength and with regard to the intensity of the incident radiation and can therefore be used for a large number of laser systems. Thus, the adjustment means or means of a specific calibration element can be reliably configured for a main emission wavelength selected from a wide spectral range and for high emission powers, which can even be in the range of several hundred watts up to several kilowatts.

If the adaptation means is designed as a dielectric mirror, the incident radiation impinging on the mirror can be kept away from the interaction area to an adjustable extent, so to speak. As a result, the amount of radiation that reaches the interaction area and interacts there with the interaction area in at least one way, namely is dissipated there, is reduced in a definable manner. It is thus possible to provide a suitable calibration element even for high intensities of the incident radiation. Because the more of the incident radiation, in particular the main radiation wavelength, does not reach the interaction area due to the choice of the dielectric mirror and adjustment of its reflectivity, for example, and is therefore available there for dissipation, the better the calibration element is suitable for larger intensities of the incident radiation.

If the adaptation means is designed as a matrix and is provided within the interaction area and/or is designed as a metallic mirror and is itself designed as the at least one interaction area, for example, it is advantageously possible to adjust to a certain extent how strongly the interaction area interacts with the incident radiation in at least one way, how strongly the radiation is dissipated there. It is thus possible to provide a suitable calibration element even for high intensities of the incident radiation. Because the weaker the interaction and thus the dissipation of the radiation, in particular of the main emission wavelength, through the selection of a corresponding matrix or through the adjustment of the reflectivity of the metallic mirror, the more suitable the calibration element is for greater intensities of the incident radiation.

Especially in the case of the metallic mirror, it is advantageous if the metallic mirror is identical to the interaction area. The reflectivity of the metallic mirror thus allows the dissipation capacity of the interaction region to be adjusted to a certain extent, in particular its heating, and thus the modifiability, in particular the ablatability, of the coating.

Thus, the level of detail of the test pattern that can be written into the calibration element with the respective laser system can be improved by the matching means, in particular with regard to the main emission wavelength of the laser source, such as dielectric mirror, metallic mirror and/or matrix.

The dielectric mirror, the metallic mirror and the matrix can each also be realized for one or more wavelengths, selected from a wide spectral range, and therefore make it possible to provide a suitable calibration element in a particularly flexible manner for different laser systems.

The adjustment means or means, in particular the dielectric mirror, the metallic mirror and/or the matrix, is and/or are advantageously each adapted for light of the main emission wavelength.

Advantageously, the adjustment means is or are adjusted for one or more than one main emission wavelength.

The coating preferably has the dielectric mirror and/or the metallic mirror.

The metallic mirror can advantageously completely or partially form the interaction area.

The interaction area can advantageously be formed entirely or partially by the metallic mirror.

Advantageously, only a fraction of an incident radiation emitted by the high-power laser radiation source and incident on a surface of the calibration element is Wec self-acting area dissipated, in particular the surface is the at least one coated main side of the calibration element.

The laser system preferably has or represents a laser scanning system.

When it is mentioned in the present application that radiation can be dissipated in the interaction area, this is preferably understood to mean that the incident radiation in the interaction area, for example at least partially into another form of energy, at least partially into heat, at least partially into an ionization process and/or can be at least partially converted into another chemical state, such as a color change, and can thereby at least partially contribute to the coating being changeable in at least one of its parameters and/or detachable, in particular removable, from the substrate.

Accordingly, the radiation dissipated in the interaction region advantageously at least partially contributes to changing the coating in at least one of its parameters and/or detaching it from the substrate, in particular removing it, preferably at least when a defined or definable amount of dissipated radiation is exceeded, preferably due to the radiation converted into heat.

If the present application speaks of an interaction cross section, this is preferably understood to mean a measure, in particular qualitative or quantitative, such as a percentage, which indicates how strong the interaction between light entering and/or onto the interaction area is, in particular the main emission wavelength, and the interaction region and/or parts thereof fails. For example, the interaction cross section can indicate which percentage of the light that has reached and/or onto the interaction area, in particular of the main emission wavelength, is dissipated in the interaction area.

Alternatively or additionally, it can also be provided that the dielectric mirror is adapted for light of the main emission wavelength, is essentially free of absorption and/or is formed in layers, in particular has or consists of a single layer or a multi-layer system.

Preferably, at least one adjustment means or the only adjustment means is designed as a dielectric mirror and/or is comprised by the calibration element, in particular the coating.

By adapting the dielectric mirror for light to the main emission wavelength, the calibration element can be specifically adjusted to the operating wavelength of the system's laser.

The dielectric mirror advantageously extends along the entire surface of the respective principal face, preferably at a distance from the latter on which it is placed, in particular directly or indirectly, particularly in the case of a laminated dielectric mirror.

A dielectric mirror with multiple layers can advantageously be adapted to multiple different wavelengths and thus to multiple main emission wavelengths of one or more laser sources of one or more laser systems. This makes it possible to use a single calibration element for multiple laser systems and/or multiple laser sources of a single laser system. This is particularly economical.

Alternatively or additionally, it can also be provided that the dielectric mirror is arranged, in particular directly and/or at least in certain areas, on the interaction area or the interaction area is arranged in particular directly, sandwich-like and/or at least in areas, between the substrate and the dielectric mirror .

The calibration element can be manufactured particularly easily if the dielectric mirror is arranged directly on the interaction area. Even if the interaction area is arranged directly on the substrate, simple production is possible.

Alternatively or additionally, it can also be provided that the dielectric mirror occupies a larger volume than the interaction area.

As a result, the mirror can, for example, reduce the power before it reaches the interaction area and can thus also be designed particularly well for irradiation with high laser intensities.

Alternatively or additionally, it can also be provided that the calibration element is at least partially absorbing for light of the main emission wavelength, with the calibration element for light of the main emission wavelength preferably having an absorptivity of less than or equal to 1 %, preferably less than or equal to 0.1%, preferably less than or equal to 0.01%, preferably less than or equal to 0.001%.

Advantageously, the light of the main emission wavelength is absorbed at least in the interaction area.

Alternatively or additionally, it can also be provided that the dielectric mirror for light of the main emission wavelength has a degree of reflection of greater than or equal to 50%, preferably greater than or equal to 90%, preferably greater than or equal to 95%, preferably greater than or equal to 99%, preferably greater than or equal to 99.9%, preferably greater than or equal to 99.99%.

Because the degree of reflection is selected accordingly, the calibration element can be used reliably for calibrating laser systems even with high output powers and/or high intensities of the incident radiation.

Alternatively or additionally, it can also be provided that the dielectric mirror, in particular the multi-layer system of the mirror, is non-metallic and/or the interaction area for light of the main emission wavelength has a destruction threshold, and by means of the dielectric mirror an extension within a cross-sectional plane parallel to the main side of the calibration element modifications in the interaction region caused by the incident radiation is at least partially adjusted or adjustable.

In other words, the mirror is particularly well suited to limiting the radiation of the laser that is effective, that is to say dissipable, in the interaction region. As a result, modifications such as material removal due to a local exceeding of the destruction threshold can be localized very precisely. As a result, the pattern written into the calibration element with the laser can also be used particularly well for determining calibration data for calibrating the system.

Alternatively or additionally, it can also be provided that the dielectric mirror has at least 2n layers, with n (a) equal to 1 or greater, preferably 2 or greater, preferably 3 or greater, preferably 4 or greater, preferably 5 or greater, preferably 6 or greater greater, preferably 8 or greater, preferably 10 or greater, preferably 12 or greater, preferably 14 or greater, (b) equal to 20 or less, preferably 18 or less, preferably 16 or less, preferably 14 or less, preferably 12 or less, preferably 10 or less, preferably 8 or less, preferably 6 or less, preferably 5 or less, preferably 4 or less, preferably 3 or less, preferably 2 or less, and/or (c) between 1 and 20, preferably between 2 and 15, preferably between 4 and 13, preferably between 6 and 10.

Advantageously, the number of layers is odd.

Alternatively or additionally, it can also be provided that at least two successive layers of the dielectric mirror, preferably all successive layers, have a difference in refractive index (a) of 0.2 or more, preferably 0.25 or more, preferably 0.3 or more, preferably 0.35 or more, preferably 0.4 or more, preferably 0.45 or more, preferably 0.5 or more, preferably 0.55 or more, preferably 0.6 or more, preferably 0.8 or more, preferably 1.0 or more, (b) 2 or less, preferably 1.5 or less, preferably 1 or less, preferably 0.8 or less, preferably 0, 7 or less, preferably 0.6 or less, preferably 0.5 or less, preferably 0.4 or less, preferably 0.3 or less, and/or (c) between 0.2 and 2, preferably between 0.2 and 1.5, preferably between 0.2 and 1.0, preferably between 0.2 and 0.8, preferably between 0.25 and 0.7, preferably between 0.25 and 0.6, preferably between 0.3 and 0.6, preferably between 0.35 and 0.55, preferably between 0.35 and 0.45.

Such a refractive index difference, in particular a large one of more than 0.2, for example, between the individual layers makes it possible in a particularly advantageous manner to implement a highly reflecting dielectric mirror with a small number of layers.

Alternatively or additionally, it can also be provided that (a) the interaction area has a single, in particular metallic, layer and/or Ti, Mo, Zr, Al, Si, C, Ag, Cr, Ni, Hf, Nb, Ta, W and/or Cu has or consists of it and/or (b) the multilayer system of the dielectric mirror has layers of SiO ₂ and either TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , HfO ₂ , Nb ₂ O ₅ , SiON, AION, Si ₃ N ₄ or AlN, and preferably two or more than two, in particular all, consecutive layers of the dielectric mirror alternately a layer of SiO ₂ and a layer of one of the above-mentioned high-index oxides, such as alternating a layer of SiO ₂ and a layer made of TiO ₂ , alternately a layer of SiO ₂ and a layer of ZrO ₂ , alternately a layer of SiO ₂ and a layer of Ta2O ₅ , alternately a layer of SiO 2 and a layer of Nb ₂ O ₅ or alternately a layer of SiO ₂ and a layer of HfO ₂ .

The layers of the interaction area mentioned are thus produced from materials which are advantageously absorbent for the main emission wavelength. In addition, the materials are cheap in cost.

Preferably, all materials such as metals, nitrides, carbides, substoichiometric oxynitrides and/or substoichiometric oxides can be used to form the interaction area, in particular those that absorb light of the main emission wavelength, that are easy to produce and/or that are cheap in the costs are. The interaction area can optionally have other materials, preferably also those that are not absorbing for the main emission wavelength.

• (ii) die, insbesondere hochbrechenden, Schichten des dielektrischen Spiegels aus TiO₂ , ZrO₂ , Ta₂O₅ , HfO₂ , Nb₂O₅ , SiON, AION, Si_sN₄ , oder AIN jeweils eine Dicke (a) von 10 nm oder mehr, vorzugsweise von 20 nm oder mehr, vorzugsweise von 50 nm oder mehr, vorzugsweise von 100 nm oder mehr, vorzugsweise von 120 nm oder mehr, vorzugsweise 130 nm oder mehr, (b) von 150 nm oder weniger, vorzugsweise von 140 nm oder weniger, vorzugsweise von 130 nm oder weniger, vorzugsweise von 120 nm oder weniger, vorzugsweise von 110 nm oder weniger, vorzugsweise von 100 nm oder weniger, und/oder (c) zwischen 10 nm und 150 nm, vorzugsweise zwischen 20 nm und 140 nm, vorzugsweise zwischen 50 nm und 130 nm, vorzugsweise zwischen 100 nm und 130 nm, aufweisen; und/oder
• (iii) die, insbesondere niedrigbrechenden, Schichten des dielektrischen Spiegels aus SiO₂ und/oder die, insbesondere hochbrechenden, Schichten des dielektrischen Spiegels aus TiO₂ , ZrO₂ , Ta₂O₅, HfO₂, Nb₂O₅ , SiON, AION, Si_sN₄ , oder AIN jeweils eine Dicke aufweisen, die einem Viertel des mit einem Anpassungsfaktor, der vorzugsweise einen Wert von zwischen 0,8 und 1,2 hat, multiplizierten Verhältnisses von Hauptabstrahlwellenlänge und optischem Brechungsindex der jeweiligen Schicht entspricht.

Alternatively or additionally, it can also be provided that (i) the layers of the dielectric mirror made of SiO2, in particular with low refractive index, each have a thickness (a) of 10 nm or more, preferably 15 nm or more, preferably 20 nm or more 30 nm or more, preferably 50 nm or more, preferably 190 nm or more, preferably 200 nm or more, (b) 220 nm or less, preferably 210 nm or less, preferably 200 nm or less, preferably of 190 nm or less, preferably 180 nm or less, preferably 170 nm or less, preferably 160 nm or less, and/or (c) between 10 nm and 220 nm, preferably between 20 nm and 200 nm;

• (ii) the layers of the dielectric mirror, in particular high refractive index, made of TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , HfO ₂ , Nb ₂ O ₅ , SiON, AION, Si _s N ₄ , or AlN each have a thickness (a) of 10 nm or more, preferably 20 nm or more, preferably 50 nm or more, preferably 100 nm or more, preferably 120 nm or more, preferably 130 nm or more, (b) 150 nm or less, preferably of 140 nm or less, preferably 130 nm or less, preferably 120 nm or less, preferably 110 nm or less, preferably 100 nm or less, and/or (c) between 10 nm and 150 nm, preferably between 20 nm and 140 nm, preferably between 50 nm and 130 nm, preferably between 100 nm and 130 nm; and or
• (iii) the particularly low-index layers of the dielectric mirror made of SiO ₂ and/or the particularly high-index layers of the dielectric mirror made of TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , HfO ₂ , Nb ₂ O ₅ , SiON, AION , Si _s N ₄ , or AIN each have a thickness which corresponds to a quarter of the ratio of the main emission wavelength and the optical refractive index of the respective layer multiplied by a matching factor which preferably has a value of between 0.8 and 1.2.

Particularly advantageous dielectric mirrors for the calibration element can be produced with the proposed thicknesses.

Alternatively or additionally, it can also be provided that the interaction area is an oxidic matrix, such as a TiO ₂ matrix, an Al ₂ O ₃ matrix, a ZrO ₂ matrix, an HfO ₂ matrix, a Ta ₂ O ₅ matrix or a Nb ₂ O ₅ matrix.

Preferably, at least one adjustment means or the only adjustment means is designed and/or provided as a matrix within the interaction area.

An oxidic matrix can be produced in a particularly simple, inexpensive and reliable manner.

Alternatively or additionally, it can also be provided that the interaction area has a proportion of metallic or semiconducting components as interaction units in the oxidic matrix, preferably Ti in a TiO ₂ matrix, Al in an Al ₂ O ₃ matrix, Zr in a ZrO ₂ matrix , Hf in a HfO ₂ matrix, Ta in a Ta ₂ O ₅ matrix and/or Nb in a Nb ₂ O ₅ matrix.

Insofar it was recognized that by means of such interaction units, the interaction cross section can be set in a very specific and yet simple manner for one or more wavelengths and/or different intensities of the irradiated laser light.

Alternatively or additionally, it can also be provided that the interaction area has a plurality of interaction units, which are distributed in the volume of the interaction area.

When it is said here that the interaction units are distributed in the volume of the interaction region, this preferably means that the interaction units are distributed in the volume of the matrix.

Alternatively or additionally, it can also be provided that the interaction area is at least partially absorbing for light of the main emission wavelength, in particular the absorbing property of the interaction area for light of the main emission wavelength being set or adjustable at least partially by the concentration of the interaction units in the interaction area.

Alternatively or additionally, it can also be provided that the degree of absorption of the interaction area is less than or equal to 1%, preferably less than or equal to 0.1%, preferably less than or equal to 0.01%, preferably less than or equal to 0.001%.

Advantageously, the material of the interaction region itself, that is to say in particular without a matrix and/or interaction units provided therein, contributes to an absorption of light of the main emission wavelength.

Alternatively or additionally, it can also be provided that the interaction units, in particular in the volume of the interaction area, are formed (a) by metallic or semiconducting components and/or by (b) color centers, which are preferably non-stoichiometric.

Said degree of absorption is advantageously the degree of absorption of the interaction area including the matrix and optional interaction units.

Alternatively or additionally, it can also be provided that the interaction region comprises or is formed by a sputtered layer, which in particular is TiO _x with x less than 2, ZrO _x with x less than 2, Ta ₂ O _x with x less than 5, HfO _x with x less than 2, Nb ₂ O _x with x less than 5, Si ₃ N _x with x less than 4 and/or AlN _x with x less than 1, substoichiometric SiON and/or substoichiometric AION has or consists of, and/or is produced or can be produced by substoichiometric sputtering.

Color centers as interaction units have proven to be particularly advantageous since they can be used to set the absorption properties in a particularly targeted manner for one or more wavelengths. In addition, color centers have proven to be particularly well suited for high laser intensities.

Alternatively or additionally, it can also be provided that the interaction region has a single layer and/or has a thickness of 15 nm or more,
and wherein the interaction region preferably has a destruction threshold for light of the main emission wavelength, and wherein the destruction threshold of the interaction region is at least partially set or adjustable via the concentration of the interaction units in the interaction region.

Since the interaction area is designed as a single layer, it can be produced in a particularly simple manner. For example, this layer can be applied, preferably directly, to the substrate, for example by a sputtering process.

By adapting the concentration of the interaction units in the interaction area, the interaction cross section and thus also the dissipation behavior of the interaction area can be adjusted very specifically and with simple means. If, for example, the dissipation of incident radiation is reduced, i.e. the interaction cross section for such light (in particular with constant incident radiation) is reduced, a higher light intensity is required in order to reach the destruction threshold of the interaction region. Consequently, by controlling the damage threshold of the interaction region, the calibration element can also be realized for calibrating high-energy laser systems at regular nominal power.

Alternatively or additionally, it can also be provided that the interaction area has a substoichiometric oxide and preferably the interaction units are metallic and/or the absorbing property of the interaction area for light of the main emission wavelength is at least partially determined by the concentration of oxygen, in particular the interaction area can be produced or is produced by a sputtering process with an existing oxygen deficit.

As a result, the absorbing property of the interaction area for light of the main emission wavelength can be determined at least partially by the concentration of oxygen.

The oxygen deficit can be detectable, for example, by means of XPS (X-ray photoelectron spectroscopy).

• (ii) der Wechselwirkungsbereich herstellbar oder hergestellt ist durch Co-Sputtern oder durch Sputtern von wenigstens einem Kompositmaterial, und/oder
• (iii) die absorbierende Eigenschaft des Wechselwirkungsbereichs für Licht der Hauptabstrahlwellenlänge zumindest teilweise durch die Konzentration von absorbierenden Farbzentren und/oder metallischen Nanopartikeln, wie insbesondere aus Mo, Ti, Zr, Al, Si, Ta, Nb, Hf, Cr, W, Ag, und/oder Ni, als Wechselwirkungseinheiten bestimmt ist,

und wobei vorzugsweise der Wechselwirkungsbereich nur eine einzige Schicht aufweist.Alternatively or additionally, it can also be provided that (i) the interaction area is a stoichiometric oxide, such as TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , HfO ₂ and/or Al ₂ O ₃ , in particular with metallic nanoparticles Interaction units, a sub-stoichiometric oxide such as TiO _x , ZrO _x , HfO _x , Ta ₂ O _x Nb ₂ O _x and/or Al ₂ O _x , an oxide layer with a stoichiometric gradient, a filling factor gradient and/or a nitride,

• (ii) the interaction region can be produced or produced by co-sputtering or by sputtering at least one composite material, and/or
• (iii) the absorbing property of the interaction area for light of the main emission wavelength at least partially through the concentration of absorbing color centers and/or metallic nanoparticles, such as in particular Mo, Ti, Zr, Al, Si, Ta, Nb, Hf, Cr, W, Ag , and/or Ni, is determined as interaction units,

and preferably wherein the interaction region comprises only a single layer.

It is also an option that the interaction region has a sub-stoichiometric metal oxide based on Ti, Zr, Hf, Ta, Nb, and/or Al.

Co-sputtering allows easy and reliable fabrication of the interaction region.

Alternatively or additionally, it can also be provided that the calibration element, in particular the coating, also has an anti-reflection system for light of the main emission wavelength, with the anti-reflection system preferably being arranged directly on the interaction area, in particular on the side of the interaction area facing away from the substrate,
and wherein the antireflection system preferably has one or more individual layers, and the individual layers are preferably selected from at least one of the high-index oxides TiO ₂ and/or ZrO ₂ and/or Ta ₂ O ₅ and/or Nb ₂ O ₅ and/or HfO ₂ and /or Al ₂ O ₃ and SiO ₂ .

An anti-reflection system can reliably prevent or at least reduce reflection of the incident radiation back in the direction of the laser system. This reliably prevents damage to optics such as lenses, mirrors or other elements of the laser system caused by "reflection spots".

Exemplary layer thicknesses of the antireflection system are for layers made of TiO ₂ between 100 nm and 300 nm, for example 194 nm or 245 nm, and for layers made of SiO ₂ between 100 nm and 300 nm, for example 116 nm or 245 nm.

Alternatively or additionally, it can also be provided that the interaction cross section of the interaction area and/or the calibration element can be at least partially adjusted, in particular reduced, by means of the metal mirror, and/or the metal mirror is formed by the interaction area and/or or represents this.

Preferably, at least one adjustment means or the only adjustment means is designed as a metallic mirror and/or is comprised by the calibration element, in particular the interaction area.

The metal mirror can also be encompassed by the calibration element and/or arranged on the interaction area, in particular directly.

Alternatively or additionally, it can also be provided that the coating has a multiplicity of interaction areas, preferably arranged one on top of the other, with each interaction area of the multiplicity of interaction areas preferably being designed individually according to one or more of the above options,
and wherein the coating, in particular the multiplicity of interaction areas, acts as an anti-reflection coating for light of the main emission wavelength and/or as a mirror at least for visible light in the wavelength range from 380 nm to 780 nm incident perpendicularly on the coated main side of the calibration element and/or for light of Main emission wavelength is set up.

By correspondingly providing a plurality of interaction areas, the calibration element can be adapted in a particularly simple and reliable manner for one or more wavelengths and intensities of the incident radiation.

For example, all or at least some of the interaction areas can be arranged directly one on top of the other.

Since an antireflection system can be formed at the same time through the coating, in particular the interaction areas, the advantages of the antireflection system can inherently be exploited. If, at the same time or instead, the coating, for example the interaction areas, forms a mirror for said visible light, the pattern written into the calibration element by means of the incident radiation can be read out very easily. For example, a normal daylight lamp is sufficient to be able to very reliably distinguish between coated and uncoated substrate areas nen, since different areas of the calibration element then reflect light of at least certain wavelength ranges differently. For this purpose, the substrate preferably has a lower degree of reflection, at least for visible light in the wavelength range from 380 nm to 780 nm incident perpendicularly on the uncoated substrate of the calibration element.

Alternatively or in addition, it can also be provided that a corresponding coating, each with at least one interaction area, is applied at least in regions on both main sides of the substrate,
and wherein each main face has a corresponding dielectric mirror, in particular with one or more features of at least one of the above options, and/or a corresponding matrix provided within the respective interaction area and/or a metallic mirror, in particular each with one or more features of at least one assigned to the above options, in particular exhibited by the respective coating,
wherein the two main sides are preferably adapted for different main emission wavelengths and/or laser powers.

Because the front and back of the calibration element are coated, the calibration element can be used several times. The two main sides can also be used during calibration for laser systems that differ in terms of the main emission wavelength and/or intensities, depending on how the main sides of the calibration element are aligned for the calibration process.

Alternatively or additionally, it can also be provided that the interaction region has a thickness (a) of 1 nm or more, preferably 5 nm or more, preferably 10 nm or more, preferably 20 nm or more, preferably 30 nm or more. preferably 40 nm or more, preferably 50 nm or more, preferably 70 nm or more, preferably 100 nm or more, (b) 500 nm or less, preferably 450 nm or less, preferably 420 nm or less, preferably 400 nm or less, preferably 300 nm or less, preferably 250 nm or less, preferably 200 nm or less, preferably 150 nm or less, and/or (c) between 1 nm and 500 nm, preferably between 10 nm and 400 nm, preferably between 10 nm and 200 nm, preferably between 10 nm and 150 nm, preferably between 10 nm and 100 nm, preferably between 30 nm and 70 nm, preferably between 40 nm and 60 nm.

A corresponding choice of thickness has proven to be particularly advantageous.

Alternatively or additionally, it can also be provided that the interaction area can be modified by the incident radiation, preferably without being ablated, in particular the color can be modified and/or it can be modified in itself or compared to a matrix in which the interaction area is embedded is.

Thus, the inscribed pattern can advantageously be recognized by a color change of the coating instead of by removing material from the coating in certain areas. As a result, the readability, in particular by machine, of the inscribed pattern can be improved.

Alternatively or additionally, it can also be provided that in the modified interaction area there is a contrast to a non-irradiated area of the interaction area for light with an analysis wavelength that differs from the main emission wavelength.

As a result, the readability, in particular by machine, of the pattern written into the calibration element by means of the laser during the calibration process can advantageously be made possible in a particularly reliable manner.

Alternatively or additionally, it can also be provided that the fraction of the incident radiation in the interaction area that is dissipated is less than 50%, preferably less than 40%, preferably less than 30%, preferably less than 20%, preferably less than 10% less than 5%, preferably less than 3%, preferably less than 1%, preferably less than 0.1%, preferably less than 0.01%, preferably less than 0.001% of the incident power.

As a result, a laser system with a high output power can advantageously also be reliably calibrated by means of the calibration element, since the pattern written into the calibration element can be very precisely delimited despite high power.

Alternatively or additionally, it can also be provided that both a dielectric mirror is provided and a matrix is provided within the interaction area and/or a metallic mirror is provided, and the dielectric mirror is preferably designed according to at least one of the above options and/or the interaction area and/or the metallic one Mirror is formed according to at least one of the above options.

The advantages of a dielectric mirror and matrix and/or metallic mirror can thus be combined, for example in order to do justice to even particularly high laser powers.

Alternatively or in addition, it can also be provided that the calibration element has a degree of reflection of greater than or equal to 10%, at least for visible light incident perpendicularly on the coated main side of the calibration element, at least one evaluation wavelength that is different from the main emission wavelength, selected from the wavelength range from 380 nm to 780 nm, preferably greater than or equal to 20%, preferably greater than or equal to 30%, preferably greater than or equal to 40%, preferably greater than or equal to 50% and/or
where the degree of reflection of the coated main side differs by 5 percentage points or more from the degree of reflection of the substrate for light of the evaluation wavelength that is incident perpendicularly in each case.

As a result, the readability, in particular by machine, of the pattern written into the calibration element by means of the laser during the calibration process can advantageously be made possible in a particularly reliable manner.

Alternatively or additionally, it can also be provided that the substrate material has an average reflectance of less than or equal to 12%, in particular less than or equal to 10%, for visible light in the wavelength range 380 nm to 780 nm incident perpendicularly on the substrate, in particular that Substrate material has a degree of reflection of less than or equal to 12%, in particular less than or equal to 10%, for light of the evaluation wavelength incident perpendicularly onto the substrate.

As a result, the readability, in particular by machine, of the pattern written into the calibration element by means of the laser during the calibration process can advantageously be made possible in a particularly reliable manner.

Alternatively or additionally, it can also be provided that the main emission wavelength is between 1025 nm and 1100 nm, or harmonics thereof, preferably the main emission wavelength is between 1030 nm and 1070 nm, in particular 1064 nm, or harmonics thereof, such as in particular 532 nm, 355 nm, 266nm.

These wavelength ranges and wavelengths are advantageous for typical laser systems.

Alternatively or additionally, it can also be provided that the interaction area is arranged directly on the substrate.

This enables the calibration element to be produced in a particularly simple and economical manner.

Alternatively or additionally, it can also be provided that the coating, preferably with a cw laser, has a destruction threshold of 0.1 MW/cm ² or greater, preferably 10 MW/cm ² or greater, preferably 100 MW/cm ² or greater, preferably 500 MW/cm ² or greater, preferably 1000 MW/cm ² or greater, preferably 2000 MW/cm ² or greater, preferably 2500 MW/cm ² or greater.

Laser systems with particularly high laser powers can also be calibrated with such a calibration element.

Alternatively or additionally, it can also be provided that the calibration element is designed in such a way that a permanent or reversible, visible structural change in the coating is achieved when using a continuous wave laser and/or a pulsed laser with more than 100 W average output power and a focusing element is irradiated onto the coated main side, as a result of which the calibration element is irradiated with a spot diameter of less than 500 μm, preferably less than 100 μm, preferably less than 50 μm.

If these criteria are met, a pattern can be reliably written into the calibration element and read from it.

Alternatively or additionally, it can also be provided that the coating has a single layer or a multi-layer system, in particular having two or more, preferably three or more, preferably four or more, preferably five or more layers.

Alternatively or additionally, it can also be provided that the coating has a thickness (a) of 10 μm or less, preferably 5 μm or less, preferably 3 μm or less, preferably 1 μm or less, preferably 800 nm or less. preferably 500nm or less, preferably 200nm or less, preferably 100nm or less, (b) 1nm or more, preferably 5nm or more, preferably 10nm or more, preferably 50nm or more , preferably 80 nm or more, preferably 100 nm or more, preferably 200 nm or more, preferably 500 nm or more, preferably 1 μm or more, preferably 5 µm or more, and/or (c) between 1 nm and 10 µm, preferably between 50 nm and 1 µm, preferably between 50 nm and 500 nm, preferably between 50 nm and 400 nm, having.

A corresponding choice of thickness has proven to be particularly advantageous.

Alternatively or additionally, it can also be provided that at least one layer, preferably all layers, of the coating each have a thickness (a) of 500 nm or less, preferably 300 nm or less, preferably 200 nm or less, preferably 100 nm or less, preferably 80 nm or less, preferably 50 nm or less, preferably 30 nm or less, preferably 20 nm or less, preferably 10 nm or less, (b) 1 nm or more, preferably 5 nm or more, preferably 10 nm or more, preferably 15 nm or more, preferably 25 nm or more, preferably 45 nm or more, preferably 75 nm or more, preferably 95 nm or more, preferably 150 nm or more more, preferably 195 nm or more, preferably 250 nm or more, preferably 400 nm or more, and/or (c) between 1 nm and 500 nm, preferably between 10 nm and 150 nm, preferably between 20 nm and 150 nm, preferably between 20 nm and 100 nm or between 80 nm and 150 nm.

A corresponding choice of thickness has proven to be particularly advantageous.

Alternatively or additionally, it can also be provided that the substrate is or has a glass ceramic, a “low expansion dielectric material” and/or a “zero thermal expansion glass” (ULE),
that the substrate has a CTE of less than or equal to 5 × 10 ^-6 /K, in particular less than or equal to 4 × 10 ^-6 /K, in particular less than or equal to 3.5 × 10 ^-6 /K,
and or
that the substrate has or consists of silicon, glass, in particular borosilicate glass, silicon carbide or glass ceramic and/or the substrate is disk-shaped, wafer-shaped or rectangular, preferably at least in one cross-sectional plane, in particular parallel to a main side.

Corresponding substrate materials are particularly robust and can therefore be used advantageously for a calibration element as proposed here.

A correspondingly low CTE leads to a high resistance of the substrate to temperature fluctuations.

Alternatively or additionally, it can also be provided that the substrate has a maximum extent, in particular in the form of an edge length or diameter, of 10 mm or more, preferably 30 mm or more, preferably 50 mm or more, preferably 100 mm or more , preferably 200 mm or more, and/or a thickness of 300 μm or more, preferably 500 μm or more, preferably 800 μm or more, preferably 1 mm or more, in particular between 1 mm and 2 mm .

Alternatively or additionally, it can also be provided that the peak-to-valley ratio, the bow, the warp and/or the flatness of the substrate is less than or equal to 100% of the substrate thickness, preferably less than or equal to 80% of the substrate thickness. preferably less than or equal to 60% of the substrate thickness, preferably less than or equal to 50% of the substrate thickness, preferably less than or equal to 30% of the substrate thickness, preferably less than or equal to 20% of the substrate thickness, preferably less than or equal to 10% of the substrate thickness, preferably less than or equal to 5% of the substrate thickness, preferably less than or equal to 3% of the substrate thickness.

The object is achieved by the invention according to a second aspect in that a use of a calibration element according to the first aspect of the invention,
as an alignment wafer in the field of high-energy laser applications,
and or
in the field of 3D printing of metals, in particular by means of powder bed fusion.

It was surprisingly found that the proposed calibration element according to the first aspect of the invention can be used particularly advantageously for said applications. In particular, laser systems with high light intensities no longer have to be operated outside of their nominal range for calibration. As a result, the laser system can be operated with exactly those operating parameters (in particular intensities of the laser source) during the calibration, which are also customary in regular use. This makes the calibration result very reliable.

For the second aspect of the invention, all the advantages that have already been described for the calibration element according to the first aspect of the invention apply accordingly. In this respect, reference can therefore be made to the previous statements.

• - Bereitstellen eines Kalibrierelements gemäß dem ersten Aspekt der Erfindung;
• - Einstrahlen mit einem Laser einer Hochleistungs-Laserstrahlungsquelle, die bei einer Hauptabstrahlwellenlänge, insbesondere von zwischen 1025 nm und 1100 nm, wie beispielsweise 1030 nm, eine mittlere Abstrahlleistung von 100 W oder mehr aufweist, des Laser-Systems auf die beschichtete Hauptseite des Kalibrierelements und Führen, insbesondere durch Kontrollieren der Stellungen der Umlenk-Spiegel, des Laserstrahls dort derart entlang eines oder mehreren definierten oder definierbaren Pfaden, wobei vorzugsweise

der Laserstrahl dort einen Durchmesser von 10 µm bis 500 µm aufweist,
der Laserstrahl dort eine Leistungsdichte von 0,1 MW/cm² bis 2,5 GW/cm² aufweist,
der Laser eine Leistung von 100 W bis 20000 W aufweist,
die Brennweite des Systems kleiner oder gleich 500 mm und/oder zwischen 100 mm und 500 mm, vorzugsweise zwischen 250 mm und 300 mm, beträgt,
und/oder
die Geschwindigkeit des geführten Laserspots auf der beschichteten Hauptseite des Kalibrierelements zwischen 0,01 m/s und 50 m/s, vorzugsweise zwischen 1 m/s und 10 m/s, beträgt;

• - Vergleichen des Testmusters mit einem Referenz-Muster und Feststellen von Abweichungen zwischen den beiden Mustern, wobei vorzugsweise die Abweichungen zumindest Abweichungen in einer x- und einer senkrecht dazu verlaufenden y-Richtung innerhalb der Ebene des Kalibrierelements darstellen;
• - Timing-Messung über eine variable Geschwindigkeit zur Synchronisierung von Scanner- und/oder Achssystem mit Lasereinschaltzeiten;
• - Bestimmen der Fokuslage; und/oder
• - Kalibrieren des Laser-Systems basierend zumindest auf den festgestellten Abweichungen, wobei das Kalibrieren insbesondere das Hinterlegen der Abweichungen in einem Speicher des Systems aufweist, vorgeschlagen wird.

The object is achieved by the invention according to a third aspect in that a method for calibrating a laser system, esp special for adapting the control of the deflection mirrors included in the system to the properties of the lens included in the system, having the method:

• - Providing a calibration element according to the first aspect of the invention;
• - Radiation with a laser from a high-power laser radiation source, which has an average radiation power of 100 W or more at a main emission wavelength, in particular between 1025 nm and 1100 nm, such as 1030 nm, of the laser system on the coated main side of the calibration element and Guide, in particular by checking the positions of the deflection mirror, the laser beam there along one or more defined or definable paths, preferably

the laser beam has a diameter of 10 µm to 500 µm there,
the laser beam has a power density of 0.1 MW/cm ² to 2.5 GW/cm ² there,
the laser has a power of 100 W to 20000 W,
the focal length of the system is less than or equal to 500 mm and/or between 100 mm and 500 mm, preferably between 250 mm and 300 mm,
and or
the speed of the guided laser spot on the coated main side of the calibration element is between 0.01 m/s and 50 m/s, preferably between 1 m/s and 10 m/s;

• - Comparing the test pattern with a reference pattern and determining deviations between the two patterns, the deviations preferably representing at least deviations in an x direction and a y direction running perpendicular thereto within the plane of the calibration element;
• - Timing measurement via a variable speed for synchronizing the scanner and/or axis system with laser switch-on times;
• - Determination of the focus position; and or
• It is proposed to calibrate the laser system based at least on the discrepancies found, with the calibration in particular having the discrepancies stored in a memory of the system.

All the advantages that have already been described for the calibration element according to the first aspect of the invention apply accordingly to the third aspect of the invention, in particular with regard to the improved calibration result of the laser system and/or with regard to the more precise pattern that can be inscribed in the calibration element. In this respect, reference can therefore be made to the previous statements.

The laser is advantageously operated at the regular operating intensity during the calibration process.

The laser system can represent or have a laser scanning system.

• - Positionierung des Kalibrierelementes so dass die Hauptseite des Kalibrierelements zumindest näherungsweise im Fokus der Abbildungsoptik des Laser-Systems liegt
• - Schreiben einer Abfolge von Linien, z.B. senkrecht zur Schreibrichtung transversal versetzten Linien gleicher Länge, wobei die Verfahrgeschwindigkeit von Linie zu Linie variiert wird;
• - Bestimmung der Verschiebung von Anfangs- und Endpunkt der Linien aus den geschriebenen Markierungen;
• - Auftragen der bestimmten Verschiebungen als Funktion der Geschwindigkeit; und/oder
• - Bestimmung der der zeitlichen Ein- und Ausschalt-Delays aus der Steigung der Daten (z.B. über lineare Regression).

The following can advantageously be provided for the timing measurement:

• - Positioning of the calibration element so that the main side of the calibration element is at least approximately in the focus of the imaging optics of the laser system
• - Writing a sequence of lines, for example perpendicular to the direction of writing transversally offset lines of the same length, the traversing speed being varied from line to line;
• - determination of the displacement of the start and end points of the lines from the written marks;
• - plotting the determined displacements as a function of speed; and or
• - Determination of the temporal switch-on and switch-off delays from the increase in the data (eg via linear regression).

• - Positionierung des Kalibrierelementes unter der Scanneroptik und/oder Verfahreinheit;
• - Einstellen einer initialen Fokuslage (vorzugsweise also der Abstand zwischen Fokussieroptik und Kalibrierelementoberfläche);
• - Schreiben eines Musters und/oder einer Figur (z.B. Linie);
• - Ändern der Fokuslage um einen Betrag Delta_z;
• - Schreiben einer weiteren Figur an unterschiedlicher transversaler Position;
• - Wiederholen der Schritte über einen definierten oder definierbaren z-Bereich, insbesondere von zwischen 2 und 3 Rayleigh-Längen, vorzugsweise symmetrisch um die erwartete Fokusposition in insbesondere mehr als 10 Schritten;
• - Beurteilen der geschriebenen Geometrie zur Identifikation der Fokuslage (je nach Substratreaktion etwa stärkster Farbumschlag, geringste Linienbreite und/oder Symmetrie) und/oder
• - Ggf. Anpassen von Laserleistung und/oder Delta_z.

The following can advantageously be provided for determining the focus position:

• - Positioning of the calibration element under the scanner optics and/or traversing unit;
• - Setting an initial focal position (preferably the distance between the focusing optics and the calibrating element surface);
• - writing a pattern and/or a figure (e.g. line);
• - changing the focus position by an amount Delta_z;
• - writing another figure at different transversal position;
• - Repeating the steps over a defined or definable z-range, in particular of between 2 and 3 Rayleigh lengths, preferably symmetrically around the expected focus position in in particular more than 10 steps;
• - Assess the written geometry to identify the focus position (depending on the substrate reaction, for example, the strongest color change, the smallest line width and/or symmetry) and/or
• - If necessary, adjust the laser power and/or Delta_z.

berechnet. Falls der Spotradius w₀ nicht bekannt ist, kann er vorteilhafterweise über den Strahlradius w₁ vor dem Objektiv und dessen Brennweite, zum Beispiel f=300 mm, zu w₀ ≈ λ₀f /πw₁ abgeschätzt werden. Für einen typischen Laser mit λ₀ = 1064 nm mit einer ausgezeichneten Strahlqualität von M²=1 (z.B. ein Faserlaser) und einem Strahldurchmesser 2w₁ = 5 mm wird folglich ein Spotradius w₀ von ca. 40 µm und daher eine Rayleigh-Länge von z_R von 4.9 mm erhalten. Daher könnte für diesen Fall der z-Bereich 10 mm gewählt werden und 1 mm Schritte gewählt werden.The Rayleigh length z _R is preferably determined from the spot radius w ₀ and the laser wavelength λ ₀ and the beam quality M ² ${\mathrm{e.g}}_R=\pi w_0^2/M^2{\lambda }_0$

calculated. If the spot radius w ₀ is not known, it can advantageously be estimated from the beam radius w ₁ in front of the lens and its focal length, for example f=300 mm, as w ₀ ≈λ ₀ f /πw ₁ . For a typical laser with λ ₀ = 1064 nm with an excellent beam quality of M ² =1 (e.g. a fiber laser) and a beam diameter 2w ₁ = 5 mm, a spot radius w ₀ of about 40 µm and therefore a Rayleigh length of z _R of 4.9 mm. Therefore, for this case, the z-range could be chosen to be 10 mm and 1 mm increments could be chosen.

The object is achieved by the invention according to a fourth aspect in that a laser system is proposed which is at least partially calibrated using a method according to the third aspect of the invention and/or by means of a calibration element according to the first aspect of the invention.

The laser system can represent or have a laser scanning system.

The object is achieved by the invention according to a fifth aspect in that a calibration element for calibrating at least one laser system that has at least one high-power laser radiation source that has a radiation power of 100 W or more at at least one main radiation wavelength,
wherein the calibration element has a substrate with two main sides and at least one coating applied at least in regions on at least one of the main sides,
wherein the coating has at least one interaction area,
wherein radiation emitted by the high-power laser radiation source can be dissipated in the interaction area and wherein the calibration element is set up such that only a fraction of an incident radiation emitted by the high-power laser radiation source and incident on a surface of the calibration element is dissipated in the interaction area, preferably at least partially by means at least one adjustment means (a) a portion of the incident radiation fed to the interaction area, for which purpose the adjustment means preferably has or represents at least one dielectric mirror comprised by the calibration element, and/or (b) an interaction cross section of the interaction area in relation to the incident radiation, for which purpose the Adaptation means preferably has or represents at least one matrix provided within the interaction area and/or has or represents at least one metallic mirror, each being adjustable.

All optional features, as described in relation to the first aspect of the invention, can advantageously be provided individually and in any combination. The adjustment means can then preferably be in the form of a dielectric mirror, a metallic mirror and/or a matrix, for which purpose the options described in relation to the first aspect of the invention can be used. Therefore, these options do not have to be repeated at this point; instead, reference can be made to the previous explanations.

character list

Further features and advantages of the invention result from the following description, in which preferred embodiments of the invention are explained with the aid of schematic drawings.

• 1 eine schematische Querschnittsansicht eines Kalibrierelements gemäß dem ersten Aspekt der Erfindung in einer ersten Ausführungsform;
• 2 eine schematische Querschnittsansicht eines Kalibrierelements gemäß dem ersten Aspekt der Erfindung in einer zweiten Ausführungsform;
• 3 eine schematische Querschnittsansicht eines Kalibrierelements gemäß dem ersten Aspekt der Erfindung in einer dritten Ausführungsform;
• 4 eine schematische Querschnittsansicht eines Kalibrierelements gemäß dem ersten Aspekt der Erfindung in einer vierten Ausführungsform;
• 5 eine schematische Illustration einer Verwendung eines Kalibrierelements gemäß dem ersten Aspekt der Erfindung;
• 6 ein Kalibrierelement gemäß dem ersten Aspekt der Erfindung mit einem eingebrachten Testmuster in einer Aufsicht; und
• 7 ein Laser-System in einer teilweisen perspektivischen Ansicht.

show:

• 1 a schematic cross-sectional view of a calibration element according to the first aspect of the invention in a first embodiment;
• 2 a schematic cross-sectional view of a calibration element according to the first aspect of the invention in a second embodiment;
• 3 a schematic cross-sectional view of a calibration element according to the first aspect of the invention in a third embodiment;
• 4 a schematic cross-sectional view of a calibration element according to the first aspect of the invention in a fourth embodiment;
• 5 a schematic illustration of a use of a calibration element according to the first aspect of the invention;
• 6 a calibration element according to the first aspect of the invention with an introduced test pattern in a top view; and
• 7 a laser system in a partial perspective view.

examples

1 shows a schematic cross-sectional view of a calibration element 101 according to FIG first aspect of the invention in a first embodiment.

The calibration element 101 has a substrate 103 . A coating 107 is applied directly to one of the main sides 105 of the substrate 103 .

The coating 107 in turn has an interaction area 109, in particular the interaction area 109 is identical to the coating 107. In the interaction area 109 radiation can be dissipated, which is emitted by a high-power laser radiation source of a laser system to be calibrated with the calibration element 101, the Radiation, in particular light, has a main emission wavelength of the laser source.

Within the interaction area 109 a matrix 111 is provided. An interaction cross section of the interaction region 109 for the radiation emitted by the high-power laser radiation source, in particular for light at a main emission wavelength of the laser source, can be adjusted by the matrix 111 .

As a result, the proportion of the incident radiation incident on the coated surface of the calibration element 101 that is dissipated in the interaction region 109 can be adjusted.

The matrix 111 can be an oxidic matrix, for example. Optionally, the interaction area 109 can have a portion (in 1 not shown) have metallic or semiconducting components as interaction units in the oxidic matrix 111. These interaction units can be distributed in the volume of the interaction area 109 .

2 shows a schematic cross-sectional view of a calibration element 201 according to the first aspect of the invention in a second embodiment.

Features that are the same as the features of the calibration element 101 are provided with the same reference numbers, but increased by 100.

The coating 207 of the calibration element 201 has a dielectric mirror 213 arranged directly on the interaction region 209 . The dielectric mirror 213 is constructed from a plurality of individual layers 215a . . . e, in particular an odd number, such as five. The layers 215a, 215c and 215e are of the same type with a low refractive index and the layers 215b and 215d are of the same type with a high refractive index. In other words, for the dielectric mirror 213 of the substrate element 203 in 2 Viewed from top to bottom, alternately low- and high-index layers are provided one on top of the other. In particular, the refractive index difference between two consecutive layers of the dielectric mirror 213 is 0.2 or more.

The dielectric mirror 213 is designed for light of a specific main emission wavelength of a laser source. For such light, the dielectric mirror 213 has a reflectance of 50% or more.

As a result, the proportion of the incident radiation of the main emission wavelength incident on the coated surface of the calibration element 201 fed to the interaction region 209 can be adjusted by means of the dielectric mirror 213 . In contrast to the calibration element 101, the interaction area 209 has no matrix for setting the interaction cross section for light of the main emission wavelength. However, this could optionally be the case.

3 shows a schematic cross-sectional view of a calibration element 301 according to the first aspect of the invention in a third embodiment.

Features that are the same as the features of the calibration element 101 or the calibration element 201 are provided with the same reference numbers, but increased by 200 or 100, respectively.

The calibration element 301 also has a dielectric mirror 313, which in the present case is made up of six layers 315a-f. The layers 315a, 315c and 315e are of the same type and the layers 315b and 315d are of the same type. The individual layers 315a-f are advantageously again alternately low and high refractive index with a difference in refractive index of more than 0.2.

The dielectric mirror 313 is designed for light of a specific main emission wavelength of a laser source. For such light, the dielectric mirror 313 has a reflectivity of 50% or more.

In contrast to the calibration element 201, however, the interaction region 309 in the calibration element 301 is in the form of a layer 315f of the dielectric mirror 313. The interaction area 309 (or the layer 315f) is constructed very similarly to the interaction area 109 of the calibration element 101, ie in particular has a matrix 311 for setting the change self-effect cross-section for light of the main emission wavelength.

Thus, the portion of the incident radiation of the main radiation wavelength incident on the coated surface of the calibration element 301 that is dissipated within the interaction region 309 can be adjusted both by means of the dielectric mirror 313 and by means of the matrix 311 through their respective design.

4 shows a schematic cross-sectional view of a calibration element 401 according to the first aspect of the invention in a fourth embodiment;

Features that are the same as the features of the calibration elements 101, 201 or 301 are provided with the same reference numbers but increased by 300, 200 or 100, respectively.

The calibration element 401 has a dielectric mirror 413 . In contrast to the dielectric mirror 313 of the calibration element 301, however, each layer 415a-f of the dielectric mirror 413 is designed as an interaction region 409 with a matrix 411 provided therein for setting the respective interaction cross section of this layer 415a-f for light of the main emission wavelength.

Layers 415a, 415c and 415e are each similar and layers 415b, 415d and 415f are each similar. That is, in particular, the matrices 411 of the layers 415a, 415c and 415e are each of the same type and the matrices 411 of the layers 415b, 415d and 415f are each of the same type. The materials of layers of the same type are also of the same type.

For example, the two types of matrices 411 can each be distinguished by different concentrations of interaction units, which are distributed in the volume of the respective interaction region 409 . As a result, the two different interaction cross sections for light of the main emission wavelength of the different layers 415a-f can be reliably adjusted.

Instead of the dielectric mirror 213, 313 and 413, an antireflection system adapted to the at least one main emission wavelength of the laser source could also be formed in the calibration elements 201, 301 and 401 through the layers 215a-e, 315a-f and 415a-f.

5 shows a schematic illustration of a use of a general calibration element 501 according to the first aspect of the invention. This can be the calibration element 101, 201, 301 or 401, for example.

For this is in 5 the situation for different types of light incident on a calibration element 501 according to the first aspect of the invention.

For one thing, in 5 the vertical incidence of light for visible, white light that covers a spectral range from 380 nm to 780 nm. The incident light is identified by a corresponding arrow labeled “VIS” (“visible” light) directed towards the calibration element 501 . As in 5 outlined, the incident VIS light is partially reflected according to the arrow labeled “VIS” pointing away from the calibration element 501. This is the case since the average degree of reflection of the coating 507 (which has at least one interaction region 509) for the incident light is 10% here.

On the other hand, in 5 the vertical light incidence for light with a main emission wavelength of 1064 nm of a laser system to be calibrated is considered. The incident light is indicated by a corresponding arrow labeled "CAL"("calibration" light) directed toward the calibration element 501 . As in 5 sketched, the incident light is reflected due to the dielectric mirror. This is illustrated by the arrow labeled “CAL” pointing away from the calibration element 501 .

As a result, the portion of the CAL radiation incident on the surface of the calibration element 501 that is dissipated in the interaction region 509 of the coating 507 can be at least partially adjusted. As a result, the coating 507 can be removed precisely in certain areas, for example by ablating, such as in particular vaporizing, the material. The removal of the material is through a jagged shape in 5 illustrated.

Since the substrate 503 has a very low average reflectance for the white light (i.e. above all in the wavelength range between 380 nm and 780 nm), namely less than 10%, when viewing the calibration element 501 under white light incidence, the uncoated area of the calibration element 501 be clearly distinguished from the coated area. Thus, by removing the coating 507 in certain areas, a test pattern with very sharp edges can be generated within the calibration element 501, which can then be evaluated very reliably under white light incidence.

Coating 507 could be formed like coating 107, 207, 307, or 407.

6 shows a calibration element 601 according to the first aspect of the invention with a test pattern 617 introduced by area-wise removal of the coating 607 of the calibration element 601 in a plan view.

The test pattern 617 represents a circle with vertically intersecting lines arranged therein and corresponds to the uncoated areas of the calibration element 601, in particular its one main side. Alternatively, a calibration element could of course also have a number of such test patterns 617, thus representing a “matrix of test patterns”. Ideally, such a "calibration matrix" would cover the entire scan field of the laser system to be calibrated. In this way, it would be possible to correct local deviations, for example the deviation of marginal rays if the processing plane of the lens is curved.

Since, when white light is incident, the intact coating 607 of the calibration element 601 reflects the white light much more strongly than the (exposed) substrate 603 does in the area of the test pattern 617, the test pattern 617 can be evaluated very reliably, as already noted above.

The test pattern 617 can then be compared with a reference pattern, for example with regard to orientation and/or position. The reference pattern represents an expected result.

The calibration element 601 could be designed like the calibration element 101, 201, 301 or 401. The coating 607 could be formed like the coating 107, 207, 307 or 407.

7 shows a laser system 701 in a partial perspective view.

The system 701, for example in the form of a laser scanning system, has a laser 703 which emits a laser beam 705a with a main emission wavelength of 1030 nm, for example. The laser beam 705a strikes a first deflection mirror 707, which can be rotated about a vertical axis X1, and is reflected there in the direction of a second deflection mirror 709, depending on the angular position of the first deflection mirror 707. The laser beam 705a then impinges on the second deflection mirror 709, which can be rotated about a horizontal axis X2. There it is reflected in the direction of an objective 711 depending on the angular position of the second deflection mirror 709 . The lens 711 images the laser beam 705a onto a working plane 713 of the system 701 .

If the system 701 is to be calibrated, there is a calibration element 717 in the working plane 713 according to the first aspect of the invention, for example the calibration element 101, 201, 301 or 401.

By adjusting the angular position of the two deflection mirrors 707 and 709, the focused laser beam 705a can be positioned within the working plane 713, in particular on the surface of the in 7 calibration element 717 shown in perspective, are moved. Examples are in 7 two beam paths 705b and 705c are shown, which can result for two different pairs of angular positions of the deflection mirrors 707, 709 for the original beam 705a.

By changing the angular positions of the two deflection mirrors 707 and 709 in a time-controlled manner, if necessary with blanking of the laser beam 705a, a test pattern 719, like that in relation to FIG 6 discussed test pattern 617, are introduced. Because where the laser beam 705a impinges on the calibration element 717, the coating 721 is removed.

In order to fully calibrate the laser system 701, the test pattern 719 generated in this way can be compared with a reference pattern. The test pattern 719 can be evaluated, for example, under the incidence of white light, since for this (particularly in the wavelength range of between 380 nm and 780 nm) the mean reflectance of the coating 721 is significantly greater than that of the substrate uncovered by removing the coating 721. For example, the test pattern 719 can be evaluated with an optical unit such as a camera and a downstream image evaluation unit.

The deviation between the generated test pattern and the reference pattern is then determined and the system 701 can be calibrated based at least on this. For this purpose, the discrepancies can be stored, for example, in a machine-readable format in the system 701, for example in an internal memory of the system 701. These deviations can then be taken into account when setting the angular positions of the two deflection mirrors 707 and 709. Influences from optical elements of the system 701, such as those of the lens 711, on the laser beam 705a can thus be corrected.

The system 701 is thus reliably calibrated using a method according to the third aspect of the invention and/or using a calibration element according to the first aspect of the invention.

The invention can also be summarized by the following advantageous statements. The content of the statements and their dependencies also form part of the overall disclosure content of this description. Those skilled in the art are able to refine the description and/or the statements.

1. 1. Kalibrierelement zum Kalibrieren zumindest eines Laser-Systems, das zumindest eine Hochleistungs-Laserstrahlungsquelle aufweist, die bei zumindest einer Hauptabstrahlwellenlänge eine Abstrahlleistung von 100 W oder mehr aufweist, wobei das Kalibrierelement ein Substrat mit zwei Hauptseiten und wenigstens eine auf zumindest einer der Hauptseiten zumindest bereichsweise aufgebrachte Beschichtung aufweist, wobei die Beschichtung zumindest einen Wechselwirkungsbereich aufweist, wobei im Wechselwirkungsbereich von der Hochleistungs-Laserstrahlungsquelle ausgestrahlte Strahlung dissipierbar ist und wobei das Kalibrierelement dazu eingerichtet ist, dass nur ein Bruchteil von einer von der Hochleistungs-Laserstrahlungsquelle ausgestrahlten und auf eine Oberfläche des Kalibrierelements einfallenden Einfallsstrahlung im Wechselwirkungsbereich dissipiert wird, zumindest teilweise indem (a) ein dem Wechselwirkungsbereich zugeführter Anteil der Einfallsstrahlung mittels eines von dem Kalibrierelement umfassten dielektrischen Spiegels und/oder (b) ein Wechselwirkungsquerschnitt des Wechselwirkungsbereichs in Bezug auf die Einfallsstrahlung mittels einer innerhalb des Wechselwirkungsbereichs vorgesehenen Matrix und/oder eines metallischen Spiegels jeweils einstellbar ist.
2. 2. Kalibrierelement nach Feststellung 1, wobei der dielektrische Spiegel für Licht der Hauptabstrahlwellenlänge angepasst ist, im Wesentlichen absorptionsfrei ist und/oder schichtförmig ausgebildet ist, insbesondere eine einzelne Schicht oder ein Mehrschichtsystem aufweist oder daraus besteht.
3. 3. Kalibrierelement nach Feststellung 2, wobei der dielektrische Spiegel, insbesondere unmittelbar und/oder zumindest bereichsweise, auf dem Wechselwirkungsbereich angeordnet ist oder wobei der Wechselwirkungsbereich, insbesondere unmittelbar, sandwichartig und/oder zumindest bereichsweise, zwischen dem Substrat und dem dielektrischen Spiegel angeordnet ist.
4. 4. Kalibrierelement nach einer der Feststellungen 2 bis 3, wobei der dielektrische Spiegel ein größeres Volumen einnimmt als der Wechselwirkungsbereich.
5. 5. Kalibrierelement nach einer der Feststellungen 1 bis 4, wobei das Kalibrierelement für Licht der Hauptabstrahlwellenlänge zumindest teilweise absorbierend ist, wobei vorzugsweise das Kalibrierelement für Licht der Hauptabstrahlwellenlänge einen Absorptionsgrad von kleiner als oder gleich 1 %, bevorzugt kleiner als oder gleich 0,1 %, bevorzugt kleiner als oder gleich 0,01 %, bevorzugt kleiner als oder gleich 0,001 %, aufweist.
6. 6. Kalibrierelement nach einer der Feststellungen 2 bis 5, wobei der dielektrische Spiegel für Licht der Hauptabstrahlwellenlänge einen Reflexionsgrad von größer als oder gleich 50%, bevorzugt größer als oder gleich 90%, bevorzugt größer als oder gleich 95%, bevorzugt größer als oder gleich 99%, bevorzugt größer oder gleich 99,9 %, bevorzugt größer oder gleich 99,99 %, aufweist.
7. 7. Kalibrierelement nach einer der Feststellungen 2 bis 6, wobei der dielektrische Spiegel, insbesondere das Mehrschichtsystem des Spiegels, nichtmetallisch ist und/oder der Wechselwirkungsbereich für Licht der Hauptabstrahlwellenlänge eine Zerstörungsschwelle aufweist, und mittels des dielektrischen Spiegels eine Ausdehnung innerhalb einer Querschnittsebene parallel zur Hauptseite des Kalibrierelements der durch die Einfallsstrahlung verursachten Modifikationen in dem Wechselwirkungsbereich zumindest teilweise eingestellt oder einstellbar ist.
8. 8. Kalibrierelement nach einer der Feststellungen 2 bis 7, wobei der dielektrische Spiegel wenigstens 2n Schichten aufweist, mit n (a) gleich 1 oder größer, vorzugsweise 2 oder größer, vorzugsweise 3 oder größer, vorzugsweise 4 oder größer, vorzugsweise 5 oder größer, vorzugsweise 6 oder größer, vorzugsweise 8 oder größer, vorzugsweise 10 oder größer, vorzugsweise 12 oder größer, vorzugsweise 14 oder größer, (b) gleich 20 oder kleiner, vorzugsweise 18 oder kleiner, vorzugsweise 16 oder kleiner, vorzugsweise 14 oder kleiner, vorzugsweise 12 oder kleiner, vorzugsweise 10 oder kleiner, vorzugsweise 8 oder kleiner, vorzugsweise 6 oder kleiner, vorzugsweise 5 oder kleiner, vorzugsweise 4 oder kleiner, vorzugsweise 3 oder kleiner, vorzugsweise 2 oder kleiner, und/oder (c) zwischen 1 und 20, vorzugsweise zwischen 2 und 15, vorzugsweise zwischen 4 und 13, vorzugsweise zwischen 6 und 10.
9. 9. Kalibrierelement nach einer der Feststellungen 2 bis 8, wobei wenigstens zwei aufeinanderfolgende Schichten des dielektrischen Spiegels, vorzugsweise alle aufeinanderfolgenden Schichten, einen Unterschied im Brechungsindex (a) von 0,2 oder mehr, vorzugsweise von 0,25 oder mehr, vorzugsweise von 0,3 oder mehr, vorzugsweise von 0,35 oder mehr, vorzugsweise von 0,4 oder mehr, vorzugsweise von 0,45 oder mehr, vorzugsweise von 0,5 oder mehr, vorzugsweise von 0,55 oder mehr, vorzugsweise von 0,6 oder mehr, vorzugsweise von 0,8 oder mehr, vorzugsweise von 1,0 oder mehr, (b) von 2 oder weniger, vorzugsweise von 1,5 oder weniger, vorzugsweise von 1 oder weniger, vorzugsweise von 0,8 oder weniger, vorzugsweise von 0,7 oder weniger, vorzugsweise von 0,6 oder weniger, vorzugsweise von 0,5 oder weniger, vorzugsweise von 0,4 oder weniger, vorzugsweise von 0,3 oder weniger, und/oder (c) von zwischen 0,2 und 2, vorzugsweise von zwischen 0,2 und 1,5, vorzugsweise von zwischen 0,2 und 1,0, vorzugsweise von zwischen 0,2 und 0,8, vorzugsweise von zwischen 0,25 und 0,7, vorzugsweise von zwischen 0,25 und 0,6, vorzugsweise von zwischen 0,3 und 0,6, vorzugsweise von zwischen 0,35 und 0,55, vorzugsweise von zwischen 0,35 und 0,45, aufweisen.
10. 10. Kalibrierelement nach einer der Feststellungen 2 bis 9, wobei
    1. (a) der Wechselwirkungsbereich eine einzige, insbesondere metallische, Schicht aufweist und/oder Ti, Mo, Zr, Al, Si, C, Ag, Cr, Ni, Hf, Nb, Ta, W und/oder Cu aufweist oder daraus besteht und/oder (b) das Mehrschichtsystem des dielektrischen Spiegels Schichten aus SiO₂ und entweder TiO₂, ZrO₂, Ta₂O₅, HfO₂, Nb₂O₅, SiON, AION, Si_sN₄ oder AIN aufweist, und vorzugsweise zwei oder mehr als zwei, insbesondere alle, aufeinanderfolgende Schichten des dielektrischen Spiegels abwechselnd eine Schicht aus SiO₂ und eine Schicht aus einem der vorstehend genannten hochbrechenden Oxide aufweisen, wie abwechselnd eine Schicht aus SiO₂ und eine Schicht aus TiO₂, abwechselnd eine Schicht aus SiO₂ und eine Schicht aus ZrO₂, abwechselnd eine Schicht aus SiO₂ und eine Schicht aus Ta₂O₅, abwechselnd eine Schicht aus SiO₂ und eine Schicht aus Nb₂O₅ oder abwechselnd eine Schicht aus SiO₂ und eine Schicht aus HfO₂.
11. 11. Kalibrierelement nach Feststellung 10, wobei
    • (i) die, insbesondere niedrigbrechenden, Schichten des dielektrischen Spiegels aus SiO₂ jeweils eine Dicke (a) von 10 nm oder mehr, vorzugsweise von 15 nm oder mehr, vorzugsweise von 20 nm oder mehr, vorzugsweise von 30 nm oder mehr, vorzugsweise von 50 nm oder mehr, vorzugsweise von 190 nm oder mehr, vorzugsweise 200 nm oder mehr, (b) von 220 nm oder weniger, vorzugsweise von 210 nm oder weniger, vorzugsweise von 200 nm oder weniger, vorzugsweise von 190 nm oder weniger, vorzugsweise von 180 nm oder weniger, vorzugsweise von 170 nm oder weniger, vorzugsweise von 160 nm oder weniger, und/oder (c) zwischen 10 nm und 220 nm, vorzugsweise zwischen 20 nm und 200 nm aufweisen;
    • (ii) die, insbesondere hochbrechenden, Schichten des dielektrischen Spiegels aus TiO₂, ZrO₂, Ta₂O₅, HfO₂, Nb₂O₅, SiON, AION, Si₃N₄, oder AIN jeweils eine Dicke (a) von 10 nm oder mehr, vorzugsweise von 20 nm oder mehr, vorzugsweise von 50 nm oder mehr, vorzugsweise von 100 nm oder mehr, vorzugsweise von 120 nm oder mehr, vorzugsweise 130 nm oder mehr, (b) von 150 nm oder weniger, vorzugsweise von 140 nm oder weniger, vorzugsweise von 130 nm oder weniger, vorzugsweise von 120 nm oder weniger, vorzugsweise von 110 nm oder weniger, vorzugsweise von 100 nm oder weniger, und/oder (c) zwischen 10 nm und 150 nm, vorzugsweise zwischen 20 nm und 140 nm, vorzugsweise zwischen 50 nm und 130 nm, vorzugsweise zwischen 100 nm und 130 nm, aufweisen; und/oder
    • (iii) die, insbesondere niedrigbrechenden, Schichten des dielektrischen Spiegels aus SiO₂ und/oder die, insbesondere hochbrechenden, Schichten des dielektrischen Spiegels aus TiO₂, ZrO₂, Ta₂O₅, HfO₂, Nb₂O₅, SiON, AlON, Si₃N₄, oder AIN jeweils eine Dicke aufweisen, die einem Viertel des mit einem Anpassungsfaktor, der vorzugsweise einen Wert von zwischen 0,8 und 1,2 hat, multiplizierten Verhältnisses von Hauptabstrahlwellenlänge und optischem Brechungsindex der jeweiligen Schicht entspricht.
12. 12. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei der Wechselwirkungsbereich eine oxidische Matrix, wie beispielsweise eine TiO₂-Matrix, eine Al₂O₃-Matrix, eine ZrO₂-Matrix, eine HfO₂-Matrix, eine Ta₂O₅-Matrix oder eine Nb₂O₅-Matrix, aufweist.
13. 13. Kalibrierelement nach Feststellung 12, wobei der Wechselwirkungsbereich einen Anteil metallischer oder halbleitender Bestandteile als Wechselwirkungseinheiten in der oxidischen Matrix aufweist, bevorzugt Ti in einer TiO₂-Matrix, Al in einer Al₂O₃-Matrix Zr in einer ZrO₂-Matrix, Hf in einer HfO₂-Matrix, Ta in einer Ta₂O₅-Matrix und/oder Nb in einer Nb₂O₅-Matrix.
14. 14. Kalibrierelement nach einer der Feststellungen 12 bis 13, wobei der Wechselwirkungsbereich eine Mehrzahl von Wechselwirkungseinheiten aufweist, die im Volumen des Wechselwirkungsbereichs verteilt sind.
15. 15. Kalibrierelement nach einer der Feststellungen 12 bis 14, wobei der Wechselwirkungsbereich für Licht der Hauptabstrahlwellenlänge zumindest teilweise absorbierend ist, wobei insbesondere die absorbierende Eigenschaft des Wechselwirkungsbereichs für Licht der Hauptabstrahlwellenlänge zumindest teilweise durch die Konzentration der Wechselwirkungseinheiten im Wechselwirkungsbereich eingestellt oder einstellbar ist.
16. 16. Kalibrierelement nach Feststellung 15, wobei der Absorptionsgrad des Wechselwirkungsbereiches kleiner als oder gleich 1 %, bevorzugt kleiner als oder gleich 0,1 %, bevorzugt kleiner als oder gleich 0,01 %, bevorzugt kleiner als oder gleich 0,001 %, ist.
17. 17. Kalibrierelement nach einer der Feststellungen 12 bis 16, wobei die Wechselwirkungseinheiten, insbesondere im Volumen des Wechselwirkungsbereichs, (a) durch metallische oder halbleitende Bestandteile und/oder durch (b) Farbzentren, die vorzugsweise nicht stöchiometrisch sind, gebildet sind.
18. 18. Kalibrierelement nach einer der Feststellungen 12 bis 17, wobei der Wechselwirkungsbereich eine gesputterte Schicht umfasst oder durch diese gebildet ist, welche insbesondere TiO_x mit x kleiner 2, ZrO_x mit x kleiner 2, Ta₂O_x mit x kleiner 5, HfO_x mit x kleiner 2, Nb₂O_x mit x kleiner 5, Si₃N_x mit x kleiner 4 und/oder AlN_x mit x kleiner 1, unterstöchiometrisches SiON und/oder unterstöchiometrisches AION aufweist oder daraus besteht, und/oder hergestellt oder herstellbar ist durch unterstöchiometrisches Sputtern.
19. 19. Kalibrierelement nach einer der Feststellungen 12 bis 18, wobei der Wechselwirkungsbereich eine einzige Schicht aufweist und/oder eine Dicke von 15 nm oder mehr aufweist, und wobei vorzugsweise der Wechselwirkungsbereich für Licht der Hauptabstrahlwellenlänge eine Zerstörungsschwelle aufweist, und wobei über die Konzentration der Wechselwirkungseinheiten in dem Wechselwirkungsbereich die Zerstörungsschwelle des Wechselwirkungsbereichs zumindest teilweise eingestellt oder einstellbar ist.
20. 20. Kalibrierelement nach einer der Feststellungen 12 bis 19, wobei der Wechselwirkungsbereich ein unterstöchiometrisches Oxid aufweist und vorzugsweise die Wechselwirkungseinheiten metallisch sind und/oder die absorbierende Eigenschaft des Wechselwirkungsbereichs für Licht der Hauptabstrahlwellenlänge zumindest teilweise durch die Konzentration von Sauerstoff bestimmt ist, insbesondere der Wechselwirkungsbereich herstellbar oder hergestellt ist durch ein Sputterverfahren bei einem bestehenden Sauerstoffdefizit.
21. 21. Kalibrierelement nach einer der Feststellungen 12 bis 20, wobei
    • (i) der Wechselwirkungsbereich ein stöchiometrisches Oxid, wie TiO₂, ZrO₂, Ta₂O₅, Nb₂O₅, HfO₂ und/oder Al₂O₃, insbesondere mit metallischen Nanopartikeln als Wechselwirkungseinheiten, ein unterstöchiometrisches Oxid, wie TiO_x, ZrO_x, HfO_x, Ta₂O_x Nb₂O_x und/oder Al₂O_x, eine Oxidschicht mit einem stöchiometrischen Gradienten, einen Füllfaktor-Gradienten und/oder ein Nitrid aufweist,
    • (ii) der Wechselwirkungsbereich herstellbar oder hergestellt ist durch Co-Sputtern oder durch Sputtern von wenigstens einem Kompositmaterial, und/oder
    • (iii) die absorbierende Eigenschaft des Wechselwirkungsbereichs für Licht der Hauptabstrahlwellenlänge zumindest teilweise durch die Konzentration von absorbierenden Farbzentren und/oder metallischen Nanopartikeln, wie insbesondere aus Mo, Ti, Zr, Al, Si, Ta, Nb, Hf, Cr, W, Ag, und/oder Ni, als Wechselwirkungseinheiten bestimmt ist, und wobei vorzugsweise der Wechselwirkungsbereich nur eine einzige Schicht aufweist.
22. 22. Kalibrierelement nach einer der Feststellungen 12 bis 21, wobei das Kalibrierelement, insbesondere die Beschichtung, ferner ein Antireflexsystem für Licht der Hauptabstrahlwellenlänge, aufweist, wobei vorzugsweise das Antireflexsystem direkt auf dem Wechselwirkungsbereich, insbesondere auf der dem Substrat abgewandten Seite des Wechselwirkungsbereichs, angeordnet ist, und wobei vorzugsweise das Antireflexsystem eine oder mehrere Einzelschichten aufweist, und vorzugsweise die Einzelschichten ausgewählt sind aus zumindest einem der hochbrechenden Oxide TiO₂ und/oder ZrO₂ und/oder Ta₂O₅ und/oder Nb₂O₅ und/oder HfO₂ und/oder Al₂O₃ und SiO₂.
23. 23. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei mittels des Metallspiegels der Wechselwirkungsquerschnitt des Wechselwirkungsbereichs und/oder des Kalibrierelements über das Reflexionsvermögen des Metallspiegels zumindest teilweise einstellbar, insbesondere reduzierbar, ist, und/oder der Metallspiegel von dem Wechselwirkungsbereich ausgebildet ist, aufgewiesen ist und/oder diesen darstellt.
24. 24. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei die Beschichtung eine Vielzahl von, vorzugsweise aufeinander angeordneten, Wechselwirkungsbereichen aufweist, wobei vorzugsweise jeder Wechselwirkungsbereich der Vielzahl von Wechselwirkungsbereichen individuell ausgeführt ist gemäß Optionen nach wenigstens einer der Feststellungen 1 oder 12 bis 23, und wobei die Beschichtung, insbesondere die Vielzahl von Wechselwirkungsbereichen, als eine Antireflex-Beschichtung für Licht der Hauptabstrahlwellenlänge und/oder als Spiegel zumindest für senkrecht auf die beschichtete Hauptseite des Kalibrierelements einfallendes sichtbares Licht im Wellenlängenbereich 380 nm bis 780 nm und/oder für Licht der Hauptabstrahlwellenlänge eingerichtet ist.
25. 25. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei auf beiden Hauptseiten des Substrats jeweils zumindest bereichsweise eine entsprechende Beschichtung mit jeweils zumindest einem Wechselwirkungsbereich aufgebracht ist, und wobei jeder Hauptseite ein entsprechender dielektrischer Spiegel, insbesondere mit einem oder mehreren Merkmalen von wenigstens einer der Feststellungen 1 bis 11, und/oder eine entsprechende innerhalb des jeweiligen Wechselwirkungsbereichs vorgesehene Matrix und/oder einen metallischen Spiegel, insbesondere jeweils mit einem oder mehreren Merkmalen von wenigstens einer der Feststellungen 1 oder 12 bis 24, zugeordnet, insbesondere von der jeweiligen Beschichtung aufgewiesen, ist, wobei vorzugsweise die beiden Hauptseiten für unterschiedliche Hauptabstrahlwellenlängen und/oder Laserleistungen angepasst sind.
26. 26. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei der Wechselwirkungsbereich eine Dicke (a) von 1 nm oder mehr, vorzugsweise von 5 nm oder mehr, vorzugsweise von 10 nm oder mehr, vorzugsweise von 20 nm oder mehr, vorzugsweise von 30 nm oder mehr, vorzugsweise von 40 nm oder mehr, vorzugsweise von 50 nm oder mehr, vorzugsweise von 70 nm oder mehr, vorzugsweise von 100 nm oder mehr, (b) 500 nm oder weniger, vorzugsweise von 450 nm oder weniger, vorzugsweise von 420 nm oder weniger, vorzugsweise von 400 nm oder weniger, vorzugsweise von 300 nm oder weniger, vorzugsweise von 250 nm oder weniger, vorzugsweise von 200 nm oder weniger, vorzugsweise von 150 nm oder weniger, und/oder (c) zwischen 1 nm und 500 nm, vorzugsweise zwischen 10 nm und 400 nm, vorzugsweise zwischen 10 nm und 200 nm, vorzugsweise zwischen 10 nm und 150 nm, vorzugsweise zwischen 10 nm und 100 nm, vorzugsweise zwischen 30 nm und 70 nm, vorzugsweise zwischen 40 nm und 60 nm, aufweist.
27. 27. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei der Wechselwirkungsbereich durch die Einfallsstrahlung, vorzugsweise ohne ablatiert zu werden, modifizierbar ist, insbesondere in der Farbe modifizierbar ist und/oder in sich selbst modifizierbar oder gegenüber einer Matrix, in welcher der Wechselwirkungsbereich eingelagert ist, modifizierbar ist.
28. 28. Kalibrierelement nach Feststellung 27, wobei im modifizierten Wechselwirkungsbereich für Licht mit einer von der Hauptabstrahlwellenlänge verschiedenen Analysewellenlänge ein Kontrast zu einem nicht bestrahlten Bereich des Wechselwirkungsbereichs vorhanden ist.
29. 29. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei der Bruchteil der Einfallsstrahlung im Wechselwirkungsbereich, der dissipiert wird, weniger als 50%, vorzugsweise weniger als 40 %, vorzugsweise weniger als 30 %, vorzugsweise weniger als 20 %, vorzugsweise weniger als 10 %, vorzugsweise weniger als 5 %, vorzugsweise weniger als 3 %, vorzugsweise weniger als 1 %, vorzugsweise weniger als 0,1 %, vorzugsweise weniger als 0,01 %, vorzugsweise weniger als 0,001 %, der Einfallsleistung ist.
30. 30. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei sowohl ein dielektrischer Spiegel vorgesehen ist als auch eine Matrix innerhalb des Wechselwirkungsbereichs und/oder ein metallischer Spiegel vorgesehen ist, und wobei vorzugsweise der dielektrische Spiegel gemäß wenigstens einer der Feststellungen 1 bis 11 ausgebildet ist und/oder der Wechselwirkungsbereich und/oder der metallische Spiegel gemäß wenigstens einer der Feststellungen 1 oder 12 bis 25 ausgebildet ist.
31. 31. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei das Kalibrierelement zumindest für senkrecht auf die beschichtete Hauptseite des Kalibrierelements einfallendes sichtbares Licht zumindest einer von der Hauptabstrahlwellenlänge unterschiedlichen Auswertewellenlänge ausgewählt aus dem Wellenlängenbereich von 380 nm bis 780 nm einen Reflexionsgrad von größer als oder gleich 10 %, vorzugsweise von größer als oder gleich 20 %, vorzugsweise von größer als oder gleich 30 %, vorzugsweise von größer als oder gleich 40 %, vorzugsweise von größer als oder gleich 50 %, aufweist und/oder wobei sich der Reflexionsgrad der beschichteten Hauptseite um 5%-Punkte oder mehr von dem Reflexionsgrad des Substrats für jeweils senkrecht auftreffendes Licht der Auswertewellenlänge unterscheidet.
32. 32. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei das Substratmaterial für senkrecht auf das Substrat einfallendes sichtbares Licht im Wellenlängenbereich 380 nm bis 780 nm einen mittleren Reflexionsgrad von kleiner als oder gleich 12 %, insbesondere von kleiner als oder gleich 10 %, aufweist, insbesondere das Substratmaterial für senkrecht auf das Substrat einfallendes Licht der Auswertewellenlänge einen Reflexionsgrad von kleiner als oder gleich 12 %, insbesondere von kleiner als oder gleich 10 %, aufweist.
33. 33. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei die Hauptabstrahlwellenlänge zwischen 1025 nm und 1100 nm, oder harmonische davon, ist, vorzugsweise die Hauptabstrahlwellenlänge zwischen 1030 nm und 1070 nm, insbesondere 1064 nm, oder harmonische davon, wie insbesondere 532 nm, 355 nm, 266 nm, ist.
34. 34. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei der Wechselwirkungsbereich unmittelbar auf dem Substrat angeordnet ist.
35. 35. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei die Beschichtung, vorzugsweise bei einem cw-Laser, eine Zerstörungsschwelle von 0,1 MW/cm² oder größer, vorzugsweise von 10 MW/cm² oder größer, vorzugsweise von 100 MW/cm² oder größer, vorzugsweise von 500 MW/cm² oder größer, vorzugsweise von 1000 MW/cm² oder größer, vorzugsweise von 2000 MW/cm² oder größer, vorzugsweise von 2500 MW/cm² oder größer, aufweist.
36. 36. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei das Kalibrierelement derart ausgebildet ist, dass eine permanente oder reversible, sichtbare Strukturänderung in der Beschichtung erzielt wird, wenn mit einem Dauerstrichlaser und/oder mit einem gepulsten Laser mit mehr als 100 W mittlerer Ausgangsleistung und einem Fokussierelement auf die beschichtete Hauptseite eingestrahlt wird, wodurch das Kalibrierelement mit einen Spotdurchmesser von kleiner als 500 µm, bevorzugt kleiner als 100 µm, bevorzugt kleiner als 50 µm, bestrahlt wird.
37. 37. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei die Beschichtung eine einzige Schicht oder ein Mehrschichtsystem, insbesondere aufweisend zwei oder mehr, vorzugsweise drei oder mehr, vorzugsweise vier oder mehr, vorzugsweise fünf oder mehr, Schichten, aufweist.
38. 38. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei die Beschichtung eine Dicke (a) von 10 µm oder weniger, vorzugsweise von 5 µm oder weniger, vorzugsweise von 3 µm oder weniger, vorzugsweise von 1 µm oder weniger, vorzugsweise von 800 nm oder weniger, vorzugsweise von 500 nm oder weniger, vorzugsweise von 200 nm oder weniger, vorzugsweise von 100 nm oder weniger, (b) von 1 nm oder mehr, vorzugsweise von 5 n oder mehr, vorzugsweise von 10 nm oder mehr, vorzugsweise von 50 nm oder mehr, vorzugsweise von 80 nm oder mehr, vorzugsweise von 100 nm oder mehr, vorzugsweise von 200 nm oder mehr, vorzugsweise von 500 nm oder mehr, vorzugsweise von 1 µm oder mehr, vorzugsweise von 5 µm oder mehr, und/oder (c) von zwischen 1 nm und 10 µm, vorzugsweise von zwischen 50 nm und 1 µm, vorzugsweise von zwischen 50 nm und 500 nm, vorzugsweise von zwischen 50 nm und 400 nm, aufweist.
39. 39. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei zumindest eine Schicht, vorzugsweise alle Schichten, der Beschichtung jeweils eine Dicke (a) von 500 nm oder weniger, vorzugsweise von 300 nm oder weniger, vorzugsweise von 200 nm oder weniger, vorzugsweise von 100 nm oder weniger, vorzugsweise von 80 nm oder weniger, vorzugsweise von 50 nm oder weniger, vorzugsweise von 30 nm oder weniger, vorzugsweise von 20 nm oder weniger, vorzugsweise von 10 nm oder weniger, (b) von 1 nm oder mehr, vorzugsweise von 5 nm oder mehr, vorzugsweise von 10 nm oder mehr, vorzugsweise von 15 nm oder mehr, vorzugsweise von 25 nm oder mehr, vorzugsweise von 45 nm oder mehr, vorzugsweise von 75 nm oder mehr, vorzugsweise von 95 nm oder mehr, vorzugsweise von 150 nm oder mehr, vorzugsweise von 195 nm oder mehr, vorzugsweise von 250 nm oder mehr, vorzugsweise von 400 nm oder mehr, und/oder (c) von zwischen 1 nm und 500 nm, vorzugsweise von zwischen 10 nm und 150 nm, vorzugsweise von zwischen 20 nm und 150 nm, vorzugsweise von zwischen 20 nm und 100 nm oder von zwischen 80 nm und 150 nm, aufweisen.
40. 40. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei das Substrat eine Glaskeramik, ein „low expansion dielectric material“ und/oder ein „zero thermal expansion glass“ (ULE) ist oder aufweist, wobei das Substrat einen CTE von kleiner oder gleich 5 × 10^-6/K, insbesondere kleiner oder gleich 4 × 10^-6/K, insbesondere kleiner oder gleich 3,5 × 10^-6/K, aufweist, und/oder wobei das Substrat Silizium, Glas, insbesondere Borosilikatglas, Siliziumkarbid oder Glaskeramik aufweist oder daraus besteht und/oder das Substrat, vorzugsweise wenigstens in einer Querschnittsebene, insbesondere parallel zu einer Hauptseite, scheibenförmig, waferförmig oder rechteckig ist.
41. 41. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei das Substrat eine maximale Ausdehnung, insbesondere in Form einer Kantenlänge oder des Durchmessers, von 10 mm oder mehr, vorzugsweise von 30 mm oder mehr, vorzugsweise von 50 mm oder mehr, vorzugsweise von 100 mm oder mehr, vorzugsweise von 200 mm oder mehr, und/oder eine Dicke von 300 µm oder mehr, vorzugsweise von 500 µm oder mehr, vorzugsweise von 800 µm oder mehr, vorzugsweise von 1 mm oder mehr, insbesondere von zwischen 1 mm und 2 mm, aufweist.
42. 42. Kalibrierelement nach einer der vorangehenden Feststellungen, wobei das peak-to-valley-verhältnis, der Bow, der Warp und/oder die Flatness des Substrats jeweils kleiner als oder gleich 100 % der Substratdicke, vorzugsweise kleiner als oder gleich 80 % der Substratdicke, vorzugsweise kleiner als oder gleich 60 % der Substratdicke, vorzugsweise kleiner als oder gleich 50 % der Substratdicke, vorzugsweise kleiner als oder gleich 30 % der Substratdicke, vorzugsweise kleiner als oder gleich 20 % der Substratdicke, vorzugsweise kleiner als oder gleich 10 % der Substratdicke, vorzugsweise kleiner als oder gleich 5 % der Substratdicke, vorzugsweise kleiner als oder gleich 3 % der Substratdicke, ist bzw. sind.
43. 43. Verwendung eines Kalibrierelements nach einer der vorangehenden Feststellungen, als Alignment-Wafer im Bereich der Hochenergie-Laser-Anwendungen, und/oder im Bereich des 3D-Drucks von Metallen, insbesondere mittels Powder Bed Fusion.
44. 44. Verfahren zur Kalibrierung eines Laser-Systems, insbesondere zur Anpassung der Steuerung der von dem System umfassten Umlenk-Spiegel an die Eigenschaften des von dem System umfassten Objektivs, das Verfahren aufweisend:
    • - Bereitstellen eines Kalibrierelements gemäß einer der Feststellungen 1 bis 42;
    • - Einstrahlen mit einem Laser einer Hochleistungs-Laserstrahlungsquelle, die bei einer Hauptabstrahlwellenlänge, insbesondere von zwischen 1025 nm und 1100 nm, wie beispielsweise 1030 nm, eine mittlere Abstrahlleistung von 100 W oder mehr aufweist, des Laser-Systems auf die beschichtete Hauptseite des Kalibrierelements und Führen, insbesondere durch Kontrollieren der Stellungen der Umlenk-Spiegel, des Laserstrahls dort derart entlang eines oder mehreren definierten oder definierbaren Pfaden, wobei vorzugsweise
      • der Laserstrahl dort einen Durchmesser von 10 µm bis 500 µm aufweist,
      • der Laserstrahl dort eine Leistungsdichte von 0,1 MW/cm² bis 2,5 GW/cm² aufweist,
      • der Laser eine Leistung von 100 W bis 20000 W aufweist,
      • die Brennweite des Systems kleiner oder gleich 500 mm und/oder zwischen 100 mm und 500 mm, vorzugsweise zwischen 250 mm und 300 mm, beträgt,
      • und/oder
      • die Geschwindigkeit des geführten Laserspots auf der beschichteten Hauptseite des Kalibrierelements zwischen 0,01 m/s und 50 m/s, vorzugsweise zwischen 1 m/s und 10 m/s, beträgt;
    • - Vergleichen des Testmusters mit einem Referenz-Muster und Feststellen von Abweichungen zwischen den beiden Mustern, wobei vorzugsweise die Abweichungen zumindest Abweichungen in einer x- und einer senkrecht dazu verlaufenden y-Richtung innerhalb der Ebene des Kalibrierelements darstellen;
    • - Timing-Messung über eine variable Geschwindigkeit zur Synchronisierung von Scanner- und/oder Achssystem mit Lasereinschaltzeiten;
    • - Bestimmen der Fokuslage; und/oder
    • - Kalibrieren des Laser-Systems basierend zumindest auf den festgestellten Abweichungen, wobei das Kalibrieren insbesondere das Hinterlegen der Abweichungen in einem Speicher des Systems aufweist.
45. 45. Laser-System, das zumindest teilweise mit einem Verfahren gemäß Feststellung 44 und/oder mittels eines Kalibrierelements gemäß einer der Feststellungen 1 bis 42 kalibriert ist.

Findings:

1. 1. Calibration element for calibrating at least one laser system that has at least one high-power laser radiation source that has a radiation power of 100 W or more at at least one main emission wavelength, the calibration element having a substrate with two main sides and at least one on at least one of the main sides has a coating applied in certain areas, the coating having at least one interaction area, wherein radiation emitted by the high-power laser radiation source can be dissipated in the interaction area, and wherein the calibration element is set up so that only a fraction of a radiation emitted by the high-power laser radiation source and applied to a surface of the The incident radiation incident on the calibration element is dissipated in the interaction area, at least partially by (a) a portion of the incident radiation supplied to the interaction area by means of a dielectric mirror comprised by the calibration element and/or (b) an interaction cross section of the interaction area in relation to the incident radiation by means of a section provided within the interaction area Matrix and / or a metallic mirror is adjustable in each case.
2. 2. Calibration element according to statement 1, wherein the dielectric mirror is adapted for light of the main emission wavelength, is essentially free of absorption and/or is formed in layers, in particular has or consists of a single layer or a multi-layer system.
3. 3. Calibration element according to statement 2, wherein the dielectric mirror is arranged, in particular directly and/or at least in certain areas, on the interaction area or wherein the interaction area is arranged, in particular directly, in a sandwich-like manner and/or at least in certain areas, between the substrate and the dielectric mirror.
4. 4. The calibration element of any one of statements 2 to 3, wherein the dielectric mirror occupies a larger volume than the interaction region.
5. 5. Calibration element according to one of the statements 1 to 4, wherein the calibration element is at least partially absorbing for light of the main emission wavelength, wherein the calibration element for light of the main emission wavelength preferably has an absorptivity of less than or equal to 1%, preferably less than or equal to 0.1% , preferably less than or equal to 0.01%, preferably less than or equal to 0.001%.
6. 6. Calibration element according to one of statements 2 to 5, wherein the dielectric mirror for light of the main emission wavelength has a degree of reflection of greater than or equal to 50%, preferably greater than or equal to 90%, preferably greater than or equal to 95%, preferably greater than or equal to 99%, preferably greater than or equal to 99.9%, preferably greater than or equal to 99.99%.
7. 7. Calibration element according to one of statements 2 to 6, wherein the dielectric mirror, in particular the multi-layer system of the mirror, is non-metallic and/or the interaction area for light of the main emission wavelength has a destruction threshold, and by means of the dielectric mirror an extension within a cross-sectional plane parallel to the main side of the calibration element of the modifications caused by the incident radiation in the interaction area is at least partially set or adjustable.
8. 8. Calibration element according to one of statements 2 to 7, wherein the dielectric mirror has at least 2n layers, with n (a) equal to 1 or greater, preferably 2 or greater, preferably 3 or greater, preferably 4 or greater, preferably 5 or greater, preferably 6 or greater, preferably 8 or greater, preferably 10 or greater, preferably 12 or greater, preferably 14 or greater, (b) equal to 20 or less, preferably 18 or less, preferably 16 or less, preferably 14 or less, preferably 12 or less, preferably 10 or less, preferably 8 or less, preferably 6 or less, preferably 5 or less, preferably 4 or less, preferably 3 or less, preferably 2 or less, and/or (c) between 1 and 20, preferably between 2 and 15, preferably between 4 and 13, preferably between 6 and 10.
9. 9. Calibration element according to any one of statements 2 to 8, wherein at least two consecutive layers of the dielectric mirror, preferably all consecutive layers, have a difference in refractive index (a) of 0.2 or more, preferably 0.25 or more, preferably 0 .3 or more, preferably 0.35 or more, preferably 0.4 or more, preferably 0.45 or more, preferably 0.5 or more, preferably 0.55 or more, preferably 0.6 or more, preferably 0.8 or more, preferably 1.0 or more, (b) 2 or less, preferably 1.5 or less, preferably 1 or less, preferably 0.8 or less, preferably 0.7 or less, preferably 0.6 or less, preferably 0.5 or less, preferably 0.4 or less, preferably 0.3 or less, and/or (c) between 0.2 and 2, preferably between 0.2 and 1.5, preferably between 0.2 and 1.0, preferably between 0.2 and 0.8, preferably between 0.25 and 0.7, preferably between 0.25 and 0.6, preferably between 0.3 and 0.6, preferably between 0.35 and 0.55, preferably between 0.35 and 0.45.
10. 10. Calibration element according to one of the statements 2 to 9, wherein
    1. (a) the interaction region has a single, in particular metallic, layer and/or has or consists of Ti, Mo, Zr, Al, Si, C, Ag, Cr, Ni, Hf, Nb, Ta, W and/or Cu and /or (b) the multilayer system of the dielectric mirror comprises layers of SiO ₂ and either TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , HfO ₂ , Nb ₂ O ₅ , SiON, AION, Si _s N ₄ or AlN, and preferably two or more than two, in particular all, successive layers of the dielectric mirror alternately have a layer of SiO ₂ and a layer of one of the abovementioned high-index oxides, such as alternately a layer of SiO ₂ and a layer of TiO ₂ , alternately a layer of SiO ₂ and a layer of ZrO ₂ , alternately a layer of SiO ₂ and a layer of Ta ₂ O ₅ , alternately a layer of SiO ₂ and a layer of Nb ₂ O ₅ or alternately a layer of SiO ₂ and a layer of HfO ₂ .
11. 11. Calibration element according to statement 10, wherein
    • (i) the, in particular low-index, layers of the dielectric mirror made of SiO ₂ each have a thickness (a) of 10 nm or more, preferably 15 nm or more, preferably 20 nm or more, preferably 30 nm or more, preferably of 50 nm or more, preferably 190 nm or more, preferably 200 nm or more, (b) 220 nm or less, preferably 210 nm or less, preferably 200 nm or less, preferably 190 nm or less, preferably of 180 nm or less, preferably 170 nm or less, preferably 160 nm or less, and/or (c) between 10 nm and 220 nm, preferably between 20 nm and 200 nm;
    • (ii) the layers of the dielectric mirror, in particular those with a high refractive index, made of TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , HfO ₂ , Nb ₂ O ₅ , SiON, AION, Si ₃ N ₄ , or AlN each have a thickness (a) of 10 nm or more, preferably 20 nm or more, preferably 50 nm or more, preferably 100 nm or more, preferably 120 nm or more, preferably 130 nm or more, (b) 150 nm or less, preferably of 140 nm or less, preferably 130 nm or less, preferably 120 nm or less, preferably 110 nm or less, preferably 100 nm or less, and/or (c) between 10 nm and 150 nm, preferably between 20 nm and 140 nm, preferably between 50 nm and 130 nm, preferably between 100 nm and 130 nm; and or
    • (iii) the particularly low-index layers of the dielectric mirror made of SiO ₂ and/or the particularly high-index layers of the dielectric mirror made of TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , HfO ₂ , Nb ₂ O ₅ , SiON, AlON , Si ₃ N ₄ , or AIN each have a thickness which corresponds to a quarter of the ratio of the main emission wavelength and the optical refractive index of the respective layer multiplied by a matching factor which preferably has a value of between 0.8 and 1.2.
12. 12. Calibration element according to one of the preceding statements, wherein the interaction area is an oxidic matrix, such as a TiO ₂ matrix, an Al ₂ O ₃ matrix, a ZrO ₂ matrix, an HfO ₂ matrix, a Ta ₂ O ₅ - Matrix or an Nb ₂ O ₅ matrix.
13. 13. Calibration element according to statement 12, wherein the interaction area has a proportion of metallic or semiconducting components as interaction units in the oxidic matrix, preferably Ti in a TiO ₂ matrix, Al in an Al ₂ O ₃ matrix, Zr in a ZrO ₂ matrix rix, Hf in a HfO ₂ matrix, Ta in a Ta ₂ O ₅ matrix and/or Nb in a Nb ₂ O ₅ matrix.
14. 14. Calibration element according to one of statements 12 to 13, wherein the interaction area has a plurality of interaction units which are distributed in the volume of the interaction area.
15. 15. Calibration element according to one of statements 12 to 14, wherein the interaction area is at least partially absorbing for light of the main emission wavelength, wherein in particular the absorbing property of the interaction area for light of the main emission wavelength is at least partially adjusted or adjustable by the concentration of the interaction units in the interaction area.
16. 16. Calibration element according to statement 15, wherein the absorbance of the interaction region is less than or equal to 1%, preferably less than or equal to 0.1%, preferably less than or equal to 0.01%, preferably less than or equal to 0.001%.
17. 17. Calibration element according to one of statements 12 to 16, wherein the interaction units, in particular in the volume of the interaction area, are formed by (a) metallic or semiconducting components and/or by (b) color centers which are preferably non-stoichiometric.
18. 18. Calibration element according to one of the statements 12 to 17, wherein the interaction region comprises a sputtered layer or is formed by this, which in particular TiO _x with x less than 2, ZrO _x with x less than 2, Ta ₂ O _x with x less than 5, HfO _x with x less than 2, Nb ₂ O _x with x less than 5, Si ₃ N _x with x less than 4 and/or AlN _x with x less than 1, has or consists of substoichiometric SiON and/or substoichiometric AION, and/or manufactured or can be produced by substoichiometric sputtering.
19. 19. Calibration element according to one of statements 12 to 18, wherein the interaction area has a single layer and/or has a thickness of 15 nm or more, and wherein the interaction area preferably has a destruction threshold for light of the main emission wavelength, and wherein the concentration of the interaction units the destruction threshold of the interaction area is at least partially set or adjustable in the interaction area.
20. 20. Calibration element according to one of statements 12 to 19, wherein the interaction area has a substoichiometric oxide and preferably the interaction units are metallic and/or the absorbing property of the interaction area for light of the main emission wavelength is at least partially determined by the concentration of oxygen, in particular the interaction area can be produced or is produced by a sputtering process with an existing oxygen deficit.
21. 21. Calibration element according to one of the statements 12 to 20, wherein
    • (i) the interaction area a stoichiometric oxide such as TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , HfO ₂ and/or Al ₂ O ₃ , in particular with metallic nanoparticles as interaction units, a sub-stoichiometric oxide such as TiO _x , ZrO _x , HfO _x , Ta ₂ O _x Nb ₂ O _x and/or Al ₂ O _x , an oxide layer with a stoichiometric gradient, a fill factor gradient and/or a nitride,
    • (ii) the interaction region can be produced or produced by co-sputtering or by sputtering at least one composite material, and/or
    • (iii) the absorbing property of the interaction area for light of the main emission wavelength at least partially through the concentration of absorbing color centers and/or metallic nanoparticles, such as in particular Mo, Ti, Zr, Al, Si, Ta, Nb, Hf, Cr, W, Ag , and/or Ni, is intended as interaction units, and wherein preferably the interaction region has only a single layer.
22. 22. Calibration element according to one of statements 12 to 21, wherein the calibration element, in particular the coating, also has an anti-reflection system for light of the main emission wavelength, the anti-reflection system preferably being arranged directly on the interaction area, in particular on the side of the interaction area facing away from the substrate , and wherein the antireflection system preferably has one or more individual layers, and preferably the individual layers are selected from at least one of the high-index oxides TiO ₂ and/or ZrO ₂ and/or Ta ₂ O ₅ and/or Nb ₂ O ₅ and/or HfO ₂ and/or Al ₂ O ₃ and SiO ₂ .
23. 23. Calibration element according to one of the preceding statements, wherein by means of the metal mirror the interaction cross section of the interaction area and/or the calibration element is Reflectivity of the metal mirror is at least partially adjustable, in particular reducible, and/or the metal mirror is formed by, has and/or represents the interaction area.
24. 24. Calibration element according to one of the preceding statements, wherein the coating has a plurality of interaction areas, preferably arranged one on top of the other, wherein preferably each interaction area of the plurality of interaction areas is designed individually according to options according to at least one of statements 1 or 12 to 23, and wherein the Coating, in particular the multiplicity of interaction areas, as an anti-reflection coating for light of the main emission wavelength and/or as a mirror at least for visible light in the wavelength range 380 nm to 780 nm incident perpendicularly on the coated main side of the calibration element and/or for light of the main emission wavelength .
25. 25. Calibration element according to one of the preceding determinations, wherein a corresponding coating each having at least one interaction area is applied at least in regions on both main sides of the substrate, and wherein each main side has a corresponding dielectric mirror, in particular with one or more features of at least one of the determinations 1 to 11, and/or a corresponding matrix provided within the respective interaction area and/or a metallic mirror, in particular each associated with one or more features of at least one of the determinations 1 or 12 to 24, in particular exhibited by the respective coating, wherein the two main sides are preferably adapted for different main emission wavelengths and/or laser powers.
26. 26. Calibration element according to one of the preceding statements, wherein the interaction region has a thickness (a) of 1 nm or more, preferably 5 nm or more, preferably 10 nm or more, preferably 20 nm or more, preferably 30 nm or more , preferably 40 nm or more, preferably 50 nm or more, preferably 70 nm or more, preferably 100 nm or more, (b) 500 nm or less, preferably 450 nm or less, preferably 420 nm or less , preferably 400 nm or less, preferably 300 nm or less, preferably 250 nm or less, preferably 200 nm or less, preferably 150 nm or less, and/or (c) between 1 nm and 500 nm, preferably between 10 nm and 400 nm, preferably between 10 nm and 200 nm, preferably between 10 nm and 150 nm, preferably between 10 nm and 100 nm, preferably between 30 nm and 70 nm, preferably between 40 nm and 60 nm.
27. 27. Calibration element according to one of the preceding statements, wherein the interaction area can be modified by the incident radiation, preferably without being ablated, in particular the color can be modified and/or it can be modified in itself or in relation to a matrix in which the interaction area is embedded, is modifiable.
28. 28. Calibration element according to statement 27, wherein a contrast to a non-irradiated area of the interaction area is present in the modified interaction area for light with an analysis wavelength that differs from the main emission wavelength.
29. 29. Calibration element according to one of the preceding statements, wherein the fraction of the incident radiation in the interaction area that is dissipated is less than 50%, preferably less than 40%, preferably less than 30%, preferably less than 20%, preferably less than 10%, preferably less than 5%, preferably less than 3%, preferably less than 1%, preferably less than 0.1%, preferably less than 0.01%, preferably less than 0.001% of the incident power.
30. 30. Calibration element according to one of the preceding determinations, wherein both a dielectric mirror is provided and a matrix is provided within the interaction area and/or a metallic mirror is provided, and wherein preferably the dielectric mirror is formed according to at least one of determinations 1 to 11 and/ or the interaction region and/or the metallic mirror is formed according to at least one of statements 1 or 12 to 25.
31. 31. Calibration element according to one of the preceding statements, wherein the calibration element has a degree of reflection of greater than or equal to 10%, at least for visible light incident perpendicularly on the coated main side of the calibration element , preferably greater than or equal to 20%, preferably greater than or equal to 30%, preferably greater than or equal to 40%, preferably greater than or equal to 50%, and/or wherein the reflectance of the coated main side differs by 5 percentage points or more from the reflectance of the substrate for light of the evaluation wavelength that is incident perpendicularly.
32. 32. Calibration element according to one of the preceding determinations, wherein the substrate material has an average reflectance of less than or equal to 12%, in particular less than or equal to 10%, for visible light in the wavelength range 380 nm to 780 nm incident perpendicularly on the substrate, in particular the substrate material has a degree of reflection of less than or equal to 12%, in particular less than or equal to 10%, for light of the evaluation wavelength incident perpendicularly onto the substrate.
33. 33. Calibration element according to one of the preceding statements, wherein the main emission wavelength is between 1025 nm and 1100 nm, or harmonics thereof, preferably the main emission wavelength is between 1030 nm and 1070 nm, in particular 1064 nm, or harmonics thereof, such as in particular 532 nm, 355 nm , 266nm.
34. 34. Calibration element according to one of the preceding statements, wherein the interaction area is arranged directly on the substrate.
35. 35. Calibration element according to one of the preceding statements, wherein the coating, preferably in the case of a cw laser, has a destruction threshold of 0.1 MW/cm ² or greater, preferably 10 MW/cm ² or greater, preferably 100 MW/cm ² or greater, preferably 500 MW/cm ² or greater, preferably 1000 MW/cm ² or greater, preferably 2000 MW/cm ² or greater, preferably 2500 MW/cm ² or greater.
36. 36. Calibration element according to one of the preceding statements, wherein the calibration element is designed in such a way that a permanent or reversible, visible structural change in the coating is achieved when using a continuous wave laser and/or a pulsed laser with more than 100 W average output power and a Focusing element is irradiated onto the coated main side, whereby the calibration element is irradiated with a spot diameter of less than 500 μm, preferably less than 100 μm, preferably less than 50 μm.
37. 37. Calibration element according to one of the preceding statements, wherein the coating has a single layer or a multi-layer system, in particular having two or more, preferably three or more, preferably four or more, preferably five or more layers.
38. 38. Calibration element according to one of the preceding statements, wherein the coating has a thickness (a) of 10 μm or less, preferably 5 μm or less, preferably 3 μm or less, preferably 1 μm or less, preferably 800 nm or less , preferably 500 nm or less, preferably 200 nm or less, preferably 100 nm or less, (b) 1 nm or more, preferably 5 n or more, preferably 10 nm or more, preferably 50 nm or more, preferably 80 nm or more, preferably 100 nm or more, preferably 200 nm or more, preferably 500 nm or more, preferably 1 µm or more, preferably 5 µm or more, and/or (c) of between 1 nm and 10 µm, preferably between 50 nm and 1 µm, preferably between 50 nm and 500 nm, preferably between 50 nm and 400 nm.
39. 39. Calibration element according to one of the preceding statements, wherein at least one layer, preferably all layers, of the coating each have a thickness (a) of 500 nm or less, preferably 300 nm or less, preferably 200 nm or less, preferably 100 nm or less, preferably 80 nm or less, preferably 50 nm or less, preferably 30 nm or less, preferably 20 nm or less, preferably 10 nm or less, (b) 1 nm or more, preferably 5 nm or more, preferably 10 nm or more, preferably 15 nm or more, preferably 25 nm or more, preferably 45 nm or more, preferably 75 nm or more, preferably 95 nm or more, preferably 150 nm or more, preferably 195 nm or more, preferably 250 nm or more, preferably 400 nm or more, and/or (c) between 1 nm and 500 nm, preferably between 10 nm and 150 nm, preferably between 20 nm and 150 nm, preferably between 20 nm and 100 nm or between 80 nm and 150 nm.
40. 40. Calibration element according to one of the preceding determinations, wherein the substrate is or has a glass ceramic, a “low expansion dielectric material” and/or a “zero thermal expansion glass” (ULE), wherein the substrate has a CTE of less than or equal to 5 × 10 ^-6 /K, in particular less than or equal to 4 × 10 ^-6 /K, in particular less than or equal to 3.5 × 10 ^-6 /K, and/or wherein the substrate comprises silicon, glass, in particular borosilicate glass, Has or consists of silicon carbide or glass ceramic and/or the substrate is disk-shaped, wafer-shaped or rectangular, preferably at least in one cross-sectional plane, in particular parallel to a main side.
41. 41. Calibration element according to one of the preceding statements, wherein the substrate has a maximum extent, in particular in the form of an edge length or diameter, of 10 mm or more, preferably 30 mm or more, preferably 50 mm or more, preferably 100 mm or more, preferably 200 mm or more, and/or a thickness of 300 µm or more, preferably 500 µm or more, preferably 800 µm or more, preferably 1 mm or more, in particular between 1 mm and 2 mm, having.
42. 42. Calibration element according to one of the preceding statements, wherein the peak-to-valley ratio, the bow, the warp and/or the flatness of the substrate are each less than or equal to 100% of the substrate thickness, preferably less than or equal to 80% of the substrate thickness , preferably less than or equal to 60% of the substrate thickness, preferably less than or equal to 50% of the substrate thickness, preferably less than or equal to 30% of the substrate thickness, preferably less than or equal to 20% of the substrate thickness, preferably less than or equal to 10% of the substrate thickness , preferably less than or equal to 5% of the substrate thickness, preferably less than or equal to 3% of the substrate thickness.
43. 43. Use of a calibration element according to one of the above statements, as an alignment wafer in the field of high-energy laser applications, and/or in the field of 3D printing of metals, in particular by means of powder bed fusion.
44. 44. Method for calibrating a laser system, in particular for adapting the control of the deflection mirrors included in the system to the properties of the lens included in the system, the method comprising:
    • - Providing a calibration according to one of the statements 1 to 42;
    • - Radiation with a laser from a high-power laser radiation source, which has an average radiation power of 100 W or more at a main emission wavelength, in particular between 1025 nm and 1100 nm, such as 1030 nm, of the laser system on the coated main side of the calibration element and Guide, in particular by checking the positions of the deflection mirror, the laser beam there along one or more defined or definable paths, preferably
      • the laser beam has a diameter of 10 µm to 500 µm there,
      • the laser beam has a power density of 0.1 MW/cm ² to 2.5 GW/cm ² there,
      • the laser has a power of 100 W to 20000 W,
      • the focal length of the system is less than or equal to 500 mm and/or between 100 mm and 500 mm, preferably between 250 mm and 300 mm,
      • and or
      • the speed of the guided laser spot on the coated main side of the calibration element is between 0.01 m/s and 50 m/s, preferably between 1 m/s and 10 m/s;
    • - Comparing the test pattern with a reference pattern and determining deviations between the two patterns, the deviations preferably representing at least deviations in an x direction and a y direction running perpendicular thereto within the plane of the calibration element;
    • - Timing measurement via a variable speed for synchronizing the scanner and/or axis system with laser switch-on times;
    • - Determination of the focus position; and or
    • - Calibrating the laser system based at least on the discrepancies found, the calibration having in particular the storing of the discrepancies in a memory of the system.
45. 45. A laser system at least partially calibrated using a method according to determination 44 and/or using a calibration element according to any one of determinations 1 to 42.

The features disclosed in the preceding description, in the claims and in the drawings can be essential for the invention in its various embodiments both individually and in any combination.

Reference List

101, 201, 301, 401, 501, 601

calibration element

103, 203, 303, 403, 503, 603

substrate

105, 205, 305, 405, 505

main page

107, 207, 307, 407, 507, 607

coating

109, 209, 309, 409, 509

interaction area

111,311,411

matrix

213, 313, 413

dielectric mirror

215a...e, 315a...f, 415a...f

layers

617

test pattern

701

laser system

703

Laser

705a-c

laser beam

707

deflection mirror

709

deflection mirror

711

lens

713

working level

717

calibration element

719

test pattern

721

coating

X1, X2

axis of rotation

Claims (20)

Calibration element for calibrating at least one laser system that has at least one high-power laser radiation source that has a radiation power of 100 W or more at at least one main radiation wavelength, wherein the calibration element has a substrate with two main sides and at least one coating applied at least in regions on at least one of the main sides, wherein the coating has at least one interaction area, wherein radiation emitted by the high-power laser radiation source can be dissipated in the interaction area and wherein the calibration element is set up such that only a fraction of an incident radiation emitted by the high-power laser radiation source and incident on a surface of the calibration element is dissipated in the interaction area, at least partially by (a ) a portion of the incident radiation fed to the interaction area can be adjusted by means of a dielectric mirror comprised by the calibration element and/or (b) an interaction cross section of the interaction area with respect to the incident radiation by means of a matrix provided within the interaction area and/or a metallic mirror. calibration element claim 1 , wherein the dielectric mirror is adapted for light of the main emission wavelength, is essentially free of absorption and/or is formed in layers, in particular has or consists of a single layer or a multi-layer system. calibration element claim 2 , wherein the dielectric mirror is arranged, in particular directly and/or at least in regions, on the interaction area or wherein the interaction area is arranged in particular directly, sandwich-like and/or at least in regions, between the substrate and the dielectric mirror. Calibration element according to one of claims 2 until 3 , wherein the dielectric mirror, in particular the multi-layer system of the mirror, is non-metallic and/or the interaction area for light of the main emission wavelength has a destruction threshold, and by means of the dielectric mirror an extension within a cross-sectional plane parallel to the main side of the calibration element of the modifications caused by the incident radiation in the Interaction area is at least partially set or adjustable. Calibration element according to one of claims 2 until 4 , wherein the dielectric mirror has at least 2n layers, with n (a) equal to 1 or greater, preferably 2 or greater, preferably 3 or greater, preferably 4 or greater, preferably 5 or greater, preferably 6 or greater, preferably 8 or greater, preferably 10 or greater, preferably 12 or greater, preferably 14 or greater, (b) equal to 20 or less, preferably 18 or less, preferably 16 or less, preferably 14 or less, preferably 12 or less, preferably 10 or less, preferably 8 or smaller, preferably 6 or smaller, preferably 5 or smaller, preferably 4 or smaller, preferably 3 or smaller, preferably 2 or smaller, and/or (c) between 1 and 20, preferably between 2 and 15, preferably between 4 and 13 , preferably between 6 and 10. Calibration element according to one of claims 2 until 5 , wherein at least two consecutive layers of the dielectric mirror, preferably all consecutive layers, a Difference in refractive index (a) of 0.2 or more, preferably 0.25 or more, preferably 0.3 or more, preferably 0.35 or more, preferably 0.4 or more, preferably 0.45 or more, preferably 0.5 or more, preferably 0.55 or more, preferably 0.6 or more, preferably 0.8 or more, preferably 1.0 or more, (b) 2 or less , preferably 1.5 or less, preferably 1 or less, preferably 0.8 or less, preferably 0.7 or less, preferably 0.6 or less, preferably 0.5 or less, preferably 0 .4 or less, preferably 0.3 or less, and/or (c) between 0.2 and 2, preferably between 0.2 and 1.5, preferably between 0.2 and 1.0, preferably of between 0.2 and 0.8, preferably between 0.25 and 0.7, preferably between 0.25 and 0.6, preferably between 0.3 and 0.6, preferably between 0.35 and 0.55, preferably between 0.35 and 0.45. Calibration element according to one of claims 2 until 6 , wherein (a) the interaction region has a single, in particular metallic, layer and/or Ti, Mo, Zr, Al, Si, C, Ag, Cr, Ni, Hf, Nb, Ta, W and/or Cu or has it and/or (b) the multilayer system of the dielectric mirror has layers of SiO ₂ and either TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , HfO ₂ , Nb ₂ O ₅ , SiON, AION, Si _s N ₄ or AlN, and preferably two or more than two, in particular all, successive layers of the dielectric mirror alternately have a layer of SiO ₂ and a layer of one of the abovementioned high-index oxides, such as alternating a layer of SiO ₂ and a layer of TiO ₂ , alternating a layer of SiO ₂ and a layer of ZrO ₂ , alternately a layer of SiO ₂ and a layer of Ta ₂ O ₅ , alternately a layer of SiO ₂ and a layer of Nb ₂ O ₅ or alternately a layer of SiO ₂ and a layer of HfO ₂ , with preferably (i) the, in particular low-index, layers of the dielectric mirror made of SiO ₂ each having a thickness (a) of 10 nm or more, preferably 15 nm or more, preferably 20 nm or more, preferably 30 nm or more, preferably 50 nm or more, preferably 190 nm or more, preferably 200 nm or more, (b) 220 nm or less, preferably 210 nm or less, preferably 200 nm or less, preferably 190 nm or less, preferably 180 nm or less, preferably 170 nm or less, preferably 160 nm or less, and/or (c) between 10 nm and 220 nm, preferably between 20 nm and 200 nm; (ii) the layers of the dielectric mirror, in particular those with a high refractive index, made of TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , HfO ₂ , Nb ₂ O ₅ , SiON, AION, Si ₃ N ₄ , or AlN each have a thickness (a) of 10 nm or more, preferably 20 nm or more, preferably 50 nm or more, preferably 100 nm or more, preferably 120 nm or more, preferably 130 nm or more, (b) 150 nm or less, preferably of 140 nm or less, preferably 130 nm or less, preferably 120 nm or less, preferably 110 nm or less, preferably 100 nm or less, and/or (c) between 10 nm and 150 nm, preferably between 20 nm and 140 nm, preferably between 50 nm and 130 nm, preferably between 100 nm and 130 nm; and/or (iii) the layers of the dielectric mirror made of SiO ₂ , in particular with a low refractive index, and/or the layers of the dielectric mirror made of TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , HfO ₂ , Nb ₂ O ₅ , SiON, AION, SisN ₄ , or AIN each have a thickness that corresponds to a quarter of the ratio of main emission wavelength and optical refractive index of the respective layer multiplied by a matching factor, which preferably has a value of between 0.8 and 1.2. Calibration element according to one of the preceding claims, wherein the interaction region is an oxidic matrix, such as a TiO ₂ matrix, an Al ₂ O ₃ matrix, a ZrO ₂ matrix, an HfO ₂ matrix, a Ta ₂ O ₅ matrix or a Nb ₂ O ₅ matrix. calibration element claim 8 , wherein the interaction area has a proportion of metallic or semiconducting components as interaction units in the oxidic matrix, preferably Ti in a TiO ₂ matrix, Al in an Al ₂ O ₃ matrix, Zr in a ZrO ₂ matrix, Hf in a HfO ₂ - matrix, Ta in a Ta ₂ O ₅ matrix and/or Nb in a Nb ₂ O ₅ matrix. Calibration element according to one of Claims 8 until 9 , wherein the interaction area has a plurality of interaction units, which are distributed in the volume of the interaction area. Calibration element according to one of Claims 8 until 10 , wherein the interaction area is at least partially absorbing for light of the main emission wavelength, wherein in particular the absorbing property of the interaction area for light of the main emission wavelength is at least partially adjusted or adjustable by the concentration of the interaction units in the interaction area. Calibration element according to one of Claims 8 until 11 , wherein the interaction units, in particular in the volume of the interaction area, are formed (a) by metallic or semiconducting components and/or by (b) color centers which are preferably non-stoichiometric. Calibration element according to one of Claims 8 until 12 , wherein the interaction region comprises or is formed by a sputtered layer, which in particular TiO _x with x less than 2, ZrO _x with x less than 2, Ta ₂ O _x with x less than 5, HfO _x with x less than 2, Nb ₂ O _x with x less than 5, Si ₃ N _x with x less than 4 and/or AlN _x with x less than 1, has or consists of substoichiometric SiON and/or substoichiometric AION, and/or is produced or can be produced by substoichiometric sputtering. Calibration element according to one of Claims 8 until 13 , wherein the calibration element, in particular the coating, also has an anti-reflection system for light of the main emission wavelength, the anti-reflection system preferably being arranged directly on the interaction area, in particular on the side of the interaction area facing away from the substrate, and the anti-reflection system preferably having one or more individual layers and preferably the individual layers are selected from at least one of the high-index oxides TiO ₂ and/or ZrO ₂ and/or Ta ₂ O ₅ and/or Nb ₂ O ₅ and/or HfO ₂ and/or Al ₂ O ₃ and SiO ₂ . Calibration element according to one of the preceding claims, wherein the fraction of the incident radiation in the interaction region that is dissipated is less than 50%, preferably less than 40%, preferably less than 30%, preferably less than 20%, preferably less than 10%, preferably less than 5%, preferably less than 3%, preferably less than 1%, preferably less than 0.1%, preferably less than 0.01%, preferably less than 0.001% of the incident power. Calibration element according to one of the preceding claims, wherein the coating, preferably with a cw laser, has a destruction threshold of 0.1 MW/cm ² or greater, preferably 10 MW/cm ² or greater, preferably 100 MW/cm ² or greater , preferably 500 MW/cm ² or greater, preferably 1000 MW/cm ² or greater, preferably 2000 MW/cm ² or greater, preferably 2500 MW/cm ² or greater. Calibration element according to one of the preceding claims, wherein the calibration element is designed in such a way that a permanent or reversible, visible structural change in the coating is achieved when using a continuous wave laser and/or a pulsed laser with more than 100 W average output power and a focusing element the coated main side is irradiated, as a result of which the calibration element is irradiated with a spot diameter of less than 500 μm, preferably less than 100 μm, preferably less than 50 μm. Use of a calibration element according to one of the preceding claims, as an alignment wafer in the field of high-energy laser applications, and or in the field of 3D printing of metals, in particular using powder bed fusion. Method for calibrating a laser system, in particular for adapting the control of the deflection mirrors included in the system to the properties of the lens included in the system, the method comprising: - providing a calibration element according to one of Claims 1 until 17 ; - Radiation with a laser from a high-power laser radiation source, which has an average radiation power of 100 W or more at a main emission wavelength, in particular between 1025 nm and 1100 nm, such as 1030 nm, of the laser system on the coated main side of the calibration element and Guide the laser beam there, in particular by checking the positions of the deflection mirrors, along one or more defined or definable paths, with the laser beam preferably having a diameter of 10 μm to 500 μm there, the laser beam there having a power density of 0.1 MW /cm ² to 2.5 GW/cm ² , the laser has a power of 100 W to 20000 W, the focal length of the system is less than or equal to 500 mm and/or between 100 mm and 500 mm, preferably between 250 mm and 300 mm, and/or the speed of the guided laser spot on the coated main side of the calibration element is between 0.01 m/s and 50 m/s, preferably between 1 m/s and 10 m/s; - Comparing the test pattern with a reference pattern and determining deviations between the two patterns, the deviations preferably representing at least deviations in an x direction and a y direction running perpendicular thereto within the plane of the calibration element; - Timing measurement over a variable speed ability to synchronize the scanner and/or axis system with laser switch-on times; - Determination of the focus position; and/or calibrating the laser system based at least on the discrepancies found, the calibration in particular having the discrepancies stored in a memory of the system. Laser system, at least in part with a method according to claim 19 and/or by means of a calibration element according to one of Claims 1 until 17 is calibrated.

Images