EP4205246A1 - Système laser à impulsions brèves et procédé de génération d'impulsions laser - Google Patents
Système laser à impulsions brèves et procédé de génération d'impulsions laserInfo
- Publication number
- EP4205246A1 EP4205246A1 EP21759266.6A EP21759266A EP4205246A1 EP 4205246 A1 EP4205246 A1 EP 4205246A1 EP 21759266 A EP21759266 A EP 21759266A EP 4205246 A1 EP4205246 A1 EP 4205246A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- optical system
- laser pulses
- laser
- pulse
- group delay
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims description 9
- 230000006835 compression Effects 0.000 claims abstract description 48
- 238000007906 compression Methods 0.000 claims abstract description 48
- 230000009021 linear effect Effects 0.000 claims abstract description 46
- 230000003595 spectral effect Effects 0.000 claims abstract description 44
- 239000006185 dispersion Substances 0.000 claims abstract description 39
- 230000003287 optical effect Effects 0.000 claims abstract description 35
- 230000005855 radiation Effects 0.000 claims abstract description 33
- 230000002123 temporal effect Effects 0.000 claims abstract description 11
- 238000004904 shortening Methods 0.000 claims description 7
- 239000000835 fiber Substances 0.000 description 12
- 230000003993 interaction Effects 0.000 description 10
- 238000010586 diagram Methods 0.000 description 6
- 230000006378 damage Effects 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- 230000003321 amplification Effects 0.000 description 2
- 239000003989 dielectric material Substances 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 230000009022 nonlinear effect Effects 0.000 description 2
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- 230000001427 coherent effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
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- 230000001419 dependent effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
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- 238000003379 elimination reaction Methods 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/005—Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping
- H01S3/0057—Temporal shaping, e.g. pulse compression, frequency chirping
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/35—Non-linear optics
- G02F1/3501—Constructional details or arrangements of non-linear optical devices, e.g. shape of non-linear crystals
- G02F1/3503—Structural association of optical elements, e.g. lenses, with the non-linear optical device
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/35—Non-linear optics
- G02F1/3511—Self-focusing or self-trapping of light; Light-induced birefringence; Induced optical Kerr-effect
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/35—Non-linear optics
- G02F1/365—Non-linear optics in an optical waveguide structure
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
- G02F2201/17—Multi-pass arrangements, i.e. arrangements to pass light a plurality of times through the same element, e.g. by using an enhancement cavity
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S2301/00—Functional characteristics
- H01S2301/08—Generation of pulses with special temporal shape or frequency spectrum
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/005—Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping
- H01S3/0092—Nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
- H01S3/06754—Fibre amplifiers
Definitions
- the invention relates to an optical system with a laser source that generates pulsed laser radiation consisting of a time sequence of laser pulses, and at least one pulse compression device that is arranged in the beam path and has a nonlinear medium, with the laser pulses undergoing nonlinear spectral broadening during propagation through the medium and a chirp is impressed on the laser pulses.
- the invention also relates to a method for generating laser pulses, in which pulsed laser radiation consisting of a time sequence of laser pulses is generated and the generated laser pulses are spectrally broadened non-linearly with the imposition of a chirp.
- a known approach to shortening the pulse duration is the use of non-linear effects for the coherent generation of new spectral components.
- the Corresponding non-linear interactions can occur in the amplification medium (non-linear amplification) or also in separate components that follow the optical amplifier in the beam path, namely in the form of a pulse compression device.
- the most commonly exploited nonlinear interaction of laser radiation with a medium to increase spectral bandwidth is self-phase modulation (SPM).
- SPM-induced spectral broadening can be realized in media of various geometries, eg in optical waveguides such as light-conducting fibers.
- the SPM gives the laser pulses additional frequency components, so the laser radiation gains in bandwidth.
- the laser pulses In order to be able to use the newly generated frequency components to shorten the pulse duration, the laser pulses must be as free as possible from chirp, i.e. free from different time delays of the various frequency components of the laser radiation.
- the pulse compression device therefore typically includes dispersive elements connected downstream of the non-linear medium in order to largely compensate for the chirp generated by the SPM and thereby compress the laser pulses in terms of time.
- the aim is to achieve a pulse duration that corresponds as far as possible to the generated spectral bandwidth, i.e. bandwidth-limited laser pulses with a minimum pulse duration.
- the compression factor achieved by the dispersive elements can be limited by various effects, such as ionization, achievable non-linearity, losses or a limited spectral bandwidth of the non-linear medium.
- a well-known problem is that the pulse quality of the non-linearly compressed laser pulses is not perfect and a certain proportion of the pulse energy is in secondary pulses or a temporal background of the laser radiation. This is due to the nature of SPM-induced spectral broadening, which is reflected in pronounced modulations in spectral intensity (see Agrawal, GP, 2007, Nonlinear Fiber Optics, 4th edition, Amsterdam, Academic Press). Even a perfect elimination of the chirp leaves part of the pulse energy outside of the main pulse, which has been shortened in time. It is known that the temporal pulse contrast or the pulse quality is typically reduced for larger temporal compression factors. A measure of pulse quality is that part of the total pulse energy that falls within a specific time window around the maximum intensity of the pulse.
- the object of the invention is to provide an optical system that makes it possible to generate non-linearly compressed laser pulses with improved temporal pulse contrast or with improved pulse quality.
- the invention solves this problem based on an optical system of the type specified at the outset in that the pulse compression device imposes on the laser pulses a variable group delay dispersion along the beam path, which causes at least partial compensation of the chirp.
- the invention achieves the object by a method for generating laser pulses, in which pulsed laser radiation consisting of a time sequence of laser pulses is generated and the generated laser pulses are spectrally broadened non-linearly with the imposition of a chirp, with the laser pulses being imprinted with a group delay time dispersion that is variable along the beam path is, which causes an at least partial compensation of the chirp.
- the basic idea of the invention is a pulse compression device in which the spectral broadening and the compensation of the chirp are distributed over as many individual steps as possible (in the limit infinitesimally small steps), which corresponds to (quasi-)adiabatic pulse compression.
- the compression factor ie the factor of the temporal pulse shortening, per step is kept as small as possible, as a result of which the spectral modulations in the SPM-broadened spectrum of the laser pulses are reduced.
- the compression factor per step should preferably be less than four, preferably less than three, particularly preferably less than two. This reduces the energy content in secondary pulses and effectively increases the pulse peak power.
- the laser pulse is correspondingly compressed by imposing group delay dispersion (GDD).
- GDD group delay dispersion
- the strength remains nonlinear interaction unchanged in the subsequent steps.
- the spectral broadening increases and the imposed chirp also varies per step. Accordingly, the group delay time dispersion must vary from step to step, ie along the path of the beam, in order to largely compensate for the chirp imposed in each step as appropriately as possible.
- the group delay time dispersion varies continuously or stepwise along the path of the beam.
- the non-linear compression can take place stepwise, for which purpose the non-linear medium is divided into two or more separate sections through which the laser radiation passes in succession, with each of the sections of the non-linear medium being followed in the beam path by a dispersive optical element associated with this section, with the dispersive optical elements differ from one another in terms of group delay dispersion.
- sections of the non-linear medium and dispersive elements assigned to them alternate in the course of the beam.
- Each section of the non-linear medium with the associated dispersive element is assigned to a non-linear compression step.
- the dispersive element is designed in such a way that the chirp generated in the associated step is largely compensated and thus overall spectral modulations during the non-linear compression are reduced.
- SPM is an intensity-dependent effect, which means that in areas of interaction (of the nonlinear medium with the laser radiation) of higher intensity there is more spectral broadening than in areas of lower intensity.
- a laser beam with a typical Gaussian beam profile experiences a spatially inhomogeneous spectral broadening during propagation through the nonlinear medium, eg a glass plate.
- the spectral broadening is more pronounced near the beam axis than in the edge areas further away from the beam axis.
- many applications require a spectral bandwidth of the laser pulses that is homogeneous over the beam profile.
- a well-known approach to spatially homogeneous spectral Broadening of pulsed laser radiation takes advantage of spectral broadening in a Medium that is spatially homogenized in an imaging mirror arrangement, a so-called multi-pass cell, which is designed as a stable resonator.
- the nonlinear medium in the optical system according to the invention can advantageously be located in a multipass cell through which the laser radiation passes multiple times.
- a multipass cell comprises an array of two or more (partially focusing) mirrors that redirect a laser beam coupled into the multipass cell at each reflection point such that beam propagation is confined to a predefined volume along a controlled propagation path in the multipass cell, up to the laser beam after a number of reflections and thus passages through the volume of the multipass cell, it leaves it again.
- Known configurations of multipass cells are referred to as White cells or Herriott cells, for example.
- a multipass cell for spatially homogeneous spectral broadening requires that the mirrors of the multipass cell are shaped and arranged in such a way that the multipass cell forms a stable optical resonator, which is characterized in that Gaussian beams exist as a transverse eigensolution of the resonator, which experience the desired spatial homogenization of the spectral broadening as well as transversal eigensolutions in nonlinear waveguides.
- a dielectric material e.g. a glass plate
- a gas e.g. an inert gas
- the arrangement of several non-linear elements in the multi-pass cell is also conceivable; a glass plate with varying thickness can be used, or regions with different gas pressures can be provided in the multi-pass cell.
- the damage threshold of the mirrors used to implement the multipass cell limits the compressible pulse energy or the pulse peak power that can be coupled into the cell.
- the damage threshold depends on the intensity of the laser radiation. In principle, the intensity on the mirror surfaces can be reduced by increasing the distance between the mirrors. Furthermore, it is possible to work close to a concentric mirror configuration, which results in the largest beam radii on the mirror surfaces of all symmetrical configurations. However, this configuration leads to small focuses of the laser radiation, which in turn must be taken into account in the design with regard to the non-linear interaction in the medium.
- the step-by-step compensation of the chirp according to the invention can be achieved by designing the mirrors of the multipass cell to be dispersive (e.g. as dielectric mirrors). At least one of the mirrors can be suitably segmented, with the laser radiation being successively reflected at different segments of the mirror when passing through the multipass cell multiple times. At least two of the segments of the mirror differ from each other with regard to the applied group delay time dispersion, so that with each compression step, i.e. with each passage of the laser radiation through the nonlinear media located in the multipass cell, the appropriate group delay time dispersion is impressed on the laser radiation during the subsequent reflection at the corresponding mirror in order to largely compensate for the chirp generated in each case and thereby keep the spectral modulations low.
- each compression step i.e. with each passage of the laser radiation through the nonlinear media located in the multipass cell
- the multipass cell can be designed with the associated (segmented) mirrors in such a way that the non-linear compression takes place with a subdivision into a comparatively large number of steps. Accordingly, the laser radiation passes through the multipass cell, i.e. the focus of the multipass cell, at least three times, preferably at least five times, particularly preferably at least ten times or even more than twenty times.
- the laser radiation experiences with each Step along the entire beam path an essentially constant nonlinear susceptibility.
- a sequence of multipass cells of the type described with different susceptibilities along the beam path is also conceivable.
- FIG. 1 shows a schematic representation of an optical system according to the invention as a block diagram
- FIG. 2 shows a schematic representation of a pulse compression device according to the invention, realized on the basis of light-conducting fibers;
- FIG. 3 shows a schematic representation of a pulse compression device according to the invention, realized on the basis of a multipass cell
- FIG. 4 shows diagrams of the shortening of the pulse duration, the spectrum and the pulse curve over time of non-linearly compressed laser pulses
- FIG. 5 is a diagram illustrating multi-step non-linear pulse compression according to the invention.
- FIG. 6 shows a schematic representation of mirrors segmented according to the invention of the multipass cell according to FIG.
- an input laser beam EL from pulsed laser radiation is generated by means of a laser source 1 (e.g. comprising a mode-locked fiber oscillator) with a downstream optical amplifier
- the input laser beam EL is sent to a pulse compression device 3 supplied.
- the pulse compression device 3 contains a non-linear medium (not shown in FIG. 1) which brings about a non-linear spectral broadening of the laser pulses by self-phase modulation.
- the chirp generated in this way is compensated for by dispersive elements (not shown in FIG. 1) of the pulse compression device 3, so that the laser pulses in the output laser beam AL leaving the pulse compression device 3 are (almost) bandwidth-limited.
- the spectral broadening and the compensation of the chirp in the pulse compression device are distributed over a number of individual steps in order to achieve (quasi-)adiabatic pulse compression.
- the compression factor i.e. the factor of the temporal pulse shortening, per step is kept as small as possible, which reduces the spectral modulations in the SPM-broadened spectrum of the laser pulses.
- the pulse compression device 3 comprises several sections of nonlinear fibers 4 (e.g. gas-filled hollow-core fibers or conventional step-index fibers) for spectral broadening of the laser pulses by SPM, each followed by a suitable dispersive fiber section 5, 5', 5", which imposes a suitable group delay dispersion on the laser pulses propagating through the fiber arrangement, specifically in such a way that the chirp imparted to the laser pulses in the associated nonlinear fiber section 4 is compensated for as completely as possible.
- the dispersive fiber sections 5, 5', 5" differ with regard to the imposed group delay dispersion, e.g. by suitably designing the lengths of the fiber sections 5, 5', 5".
- the non-linear pulse compression is thus divided into three individual steps. A larger number is conceivable, with the practicability reaching its limits with a very large number of steps (e.g. 20 or more).
- the pulse compression device 3 is implemented by a nonlinear multipass cell 6, which enables spatially homogeneous spectral broadening by SPM. Accordingly, the spectral broadening is homogenized in the imaging mirror arrangement of the multipass cell 6 as long as this is in the range of a stable one Mirror configurations is located, ie a Gaussian mode can be found as a transversal eigensolution.
- a dielectric material eg a glass plate
- a gas eg an inert gas
- the multi-pass cell 6 allows an almost loss-free spectral broadening and on the other hand, the non-linear interaction (in the focus) and dispersion can be adjusted largely separately from one another. Assuming that the dispersion of the nonlinear medium 7 is negligible, the dispersion of one or more mirrors 8, 8', between which the laser radiation is reflected back and forth through the multipass cell 7, can be used to produce a stepwise (i.e. after any non-linear interaction of the laser radiation with the medium 7 in the focus passage) to achieve pulse compression by compensating for the chirp.
- the mirrors 8, 8′ on which the beams of the individual passages are spatially separated from one another, are designed in terms of their dispersion properties such that the laser pulses are impressed with a group delay dispersion that varies along the beam path, i.e. from reflection to reflection, in order to compensate for the chirp .
- the mirrors 8, 8′ can advantageously be segmented for this purpose (see FIG. 6), the laser radiation being reflected successively on different segments (numbered from 1 to 20 in FIG. 6) of the mirrors 8, 8′ when passing through the multipass cell 6 several times.
- the segments of the mirrors 8, 8' differ from one another with regard to the group delay time dispersion imposed during the reflection process in order to largely compensate for the chirp appropriately for each compression step.
- the starting point is a laser pulse (Gaussian pulse) generated (and amplified) by the laser source 1 with a pulse duration of 300 fs and a pulse energy of 1 mJ.
- the laser pulses are compressed by imposing group delay dispersion. The strength of the nonlinear interaction remains unchanged in the subsequent steps.
- FIG. 4 show the (simulation) results of the stepwise pulse compression carried out in this way.
- the diagram in FIG. 4a shows the pulse duration achieved after each step and the group delay dispersion required for this in each step.
- FIGS. 4b and 4c show the result of the 27-stage pulse compression in the spectral and time domain (curves 9, 10) in comparison to the likewise simulated case of a conventional, single-stage pulse compression (curves 11, 12).
- the spectral width has increased to 42.7 nm, the 300 fs input pulse is compressed to 28.5 fs.
- the decisive factor is the pulse energy content in a +/-50 fs window around the pulse maximum, which amounts to 90% of the total pulse energy and is therefore significantly higher than in the case of single-stage nonlinear compression also shown, where only 73% of the total pulse energy is contained in the same time window are.
- the example in FIG. 4 is only intended to illustrate the approach of the invention and not to represent an optimized solution. A further increase in the pulse contrast is possible by adjusting the number of steps, the strength of the non-linearity per step and the chirp compensation per step.
- FIG. 5 illustrates the pulse duration achieved for the mirror design of FIG. 6 after each step and the group delay dispersion required for each step.
- the starting point is again a 300 fs laser pulse with 1 mJ pulse energy.
- the following three steps consist of non-linear spectral broadening and -1000 fs 2 group delay dispersion each, followed by three steps of non-linear spectral broadening and -500 fs 2 group delay dispersion each and finally a pass through the non-linear medium 7 and finally once -200 fs 2 group delay dispersion.
- the original spectral bandwidth of the laser pulses of 5.234 nm is increased to 45.8 nm bandwidth (FWHM).
- the compressed pulse duration is 28.6 fs at the end, and the energy content in the +/-50 fs window around the pulse maximum is 89% and is therefore very close to the value of the finely graded non-linear compression shown in Figure 4 (there with 27 Steps) with significantly simplified realizability by means of the segmented mirrors 8, 8' shown in FIG.
- Each of the two mirrors 8, 8' of Figure 6 consists of ten segments, the first twelve segments over which the beam path passes (numbered 1 -12) have a vanishing group delay time dispersion, segment 13 on mirror 8' has a group delay time dispersion of -7000 fs 2 , segments 14 and 16 on mirror 8 and segment 15 on mirror 8' have a group delay dispersion of -1000 fs 2 , segment 18 on mirror 8 and segments 17 and 19 on mirror 8' have a group delay dispersion of -500 fs 2 and segment 20 on mirror 8 again has a vanishing group delay dispersion (in this case the last compression step happens outside the multipass cell).
- FIG. 6 shows an example for the purpose of illustration and not an optimized configuration. It should also be pointed out that the function according to the invention does not necessarily have to be implemented in a multipass cell. 20 individual, at least partially curved mirrors with corresponding characteristics in terms of dispersion, or imparting the dispersion not through the mirrors but through additional elements, provide an identical result, for example. Likewise, only one non-linear element does not necessarily have to be used.
- the pulse peak power which increases when the non-linear medium is passed through several times, should not lead to undesirable effects in the multi-pass cell.
- undesirable effects such as the destruction of the mirrors, disturbing ionization in the focus between the mirrors or too strong a non-linear interaction per focus pass. This would manifest itself in a deterioration in the spatial-spectral homogeneity of the laser beam in the output beam AL.
- These limiting effects must be taken into account when designing the multipass cell 6 .
- a possible solution is a sequence of multipass cells of the type described with different non-linearity and/or different mirror configuration (eg with regard to radii of curvature and spacing).
- an adiabatic non-linear pulse compression in a series arrangement of two or more multi-pass cells of the type according to the invention, each with adapted mirrors and non-linear media, in order to generate a pulse duration in the range of only a few optical cycles while at the same time having a high temporal quality.
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- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- Electromagnetism (AREA)
- Optics & Photonics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- General Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Lasers (AREA)
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
Abstract
L'invention concerne un système optique comprenant : une source laser (1) qui génère un rayonnement laser pulsé constitué d'une séquence temporelle d'impulsions laser ; et au moins un dispositif de compression d'impulsions (3) qui est situé dans le trajet du faisceau et qui présente un milieu non linéaire (7), les impulsions laser subissant un élargissement spectral non linéaire pendant la propagation à travers le milieu (7), et un chirp étant appliqué aux impulsions laser. L'objectif de l'invention est de mettre au point un système optique permettant de produire des impulsions laser à compression non linéaire présentant un contraste d'impulsion temporel amélioré ou une qualité d'impulsion améliorée. Selon l'invention, une dispersion de retard de groupe qui varie le long du trajet de faisceau et qui compense au moins partiellement le chirp est appliquée aux impulsions laser par le dispositif de compression d'impulsions (3).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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DE102020122731.0A DE102020122731A1 (de) | 2020-08-31 | 2020-08-31 | Kurzpuls-Lasersystem und Verfahren zur Erzeugung von Laserpulsen |
PCT/EP2021/071936 WO2022043021A1 (fr) | 2020-08-31 | 2021-08-05 | Système laser à impulsions brèves et procédé de génération d'impulsions laser |
Publications (1)
Publication Number | Publication Date |
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EP4205246A1 true EP4205246A1 (fr) | 2023-07-05 |
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EP21759266.6A Pending EP4205246A1 (fr) | 2020-08-31 | 2021-08-05 | Système laser à impulsions brèves et procédé de génération d'impulsions laser |
Country Status (5)
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US (1) | US20230335964A1 (fr) |
EP (1) | EP4205246A1 (fr) |
CN (1) | CN116529667A (fr) |
DE (1) | DE102020122731A1 (fr) |
WO (1) | WO2022043021A1 (fr) |
Family Cites Families (1)
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US9240663B2 (en) * | 2013-11-14 | 2016-01-19 | Coherent, Inc. | Tunable femtosecond laser-pulse source including a super-continuum generator |
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2020
- 2020-08-31 DE DE102020122731.0A patent/DE102020122731A1/de active Pending
-
2021
- 2021-08-05 US US18/023,753 patent/US20230335964A1/en active Pending
- 2021-08-05 EP EP21759266.6A patent/EP4205246A1/fr active Pending
- 2021-08-05 CN CN202180070447.4A patent/CN116529667A/zh active Pending
- 2021-08-05 WO PCT/EP2021/071936 patent/WO2022043021A1/fr active Application Filing
Also Published As
Publication number | Publication date |
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DE102020122731A1 (de) | 2022-03-03 |
US20230335964A1 (en) | 2023-10-19 |
CN116529667A (zh) | 2023-08-01 |
WO2022043021A1 (fr) | 2022-03-03 |
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