WO2008125327A1 - Procédé et système de positionnement reproductible d'un objet cible dans le volume d'action d'un faisceau laser - Google Patents

Procédé et système de positionnement reproductible d'un objet cible dans le volume d'action d'un faisceau laser Download PDF

Info

Publication number
WO2008125327A1
WO2008125327A1 PCT/EP2008/002956 EP2008002956W WO2008125327A1 WO 2008125327 A1 WO2008125327 A1 WO 2008125327A1 EP 2008002956 W EP2008002956 W EP 2008002956W WO 2008125327 A1 WO2008125327 A1 WO 2008125327A1
Authority
WO
WIPO (PCT)
Prior art keywords
image
target object
optics
effective volume
laser radiation
Prior art date
Application number
PCT/EP2008/002956
Other languages
German (de)
English (en)
Inventor
Ralph Jung
Original Assignee
Heinrich-Heine-Universität Düsseldorf
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Heinrich-Heine-Universität Düsseldorf filed Critical Heinrich-Heine-Universität Düsseldorf
Publication of WO2008125327A1 publication Critical patent/WO2008125327A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/04—Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/062—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam
    • B23K26/0622—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses
    • B23K26/0624—Shaping the laser beam, e.g. by masks or multi-focusing by direct control of the laser beam by shaping pulses using ultrashort pulses, i.e. pulses of 1ns or less
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/073—Shaping the laser spot

Definitions

  • the invention relates to a method for the reproducible positioning of a target object in the effective volume of a first laser radiation, in particular pulsed laser radiation, which is highly reflective for the wavelength of the first laser radiation and transmissive for at least a second laser radiation by means of a focusing optics in the Effective volume is focusable.
  • the invention further relates to a system having the same features, in particular for carrying out the method.
  • the invention is based on the fact that it is known in the art with laser pulses, in particular high-intensity laser pulses with powers of terawatts (10 12 watts) or more, to illuminate target objects, the so-called targets, and thus to produce physically desired processes, which are largely dependent on depend on the achieved light intensity in the focus.
  • very strong particle beams with these properties can be generated in an extremely short time, for example, less than 10 picoseconds (10 "12 seconds), which are of interest for medical applications such as cancer radiotherapy or the production of short-lived radiopharmaceuticals . It is also possible with the aid of lasers to produce ultrashort coherent X-ray pulses, which are extremely interesting in addition to their use in medicine, for example in microchip production, ie for lithographic processes.
  • beam focusing is usually carried out with mirror optics of the shortest possible focal length, rather than with lenses, in order to maximize the intensity in the focal spot on the material of the target object which is to be used for the production of particles or X-radiation, as well as an extension of the pulse duration by dispersive Avoid effects when passing through the optical material.
  • the area of highest intensity is achieved only in a very small effective volume, so that for maximum efficiency the distance between the focusing optics and the surface of the target object must be set very precisely, usually to within a few micrometers.
  • focusing optics in these high-intensity pulses can be formed by focusing mirror, parabolic focusing mirror in particular, which may have very high masses of several 10 kilos, whereas the target objects usually form only a few microns large arrangements, such as metal - or plastic films.
  • the object of the invention is to provide a method of the aforementioned generic type and a system with which a reproducible positioning of a target object can be achieved, in particular to achieve high yields or repetition rates and in particular a shot to shot reproducibility. It is a further object of the invention to provide a method and an apparatus with which the focusing of the laser beam on a target object quickly, accurately, quantifiable and beyond even in further delimitation from the prior art destructive or without influence on the target object feasible is.
  • the object is achieved according to the invention in that to the desired position of a target object to be positioned in the effective volume of the first, in particular pulsed laser radiation, the image of a mask element by the deflection optics is projected, in particular with a second laser radiation, and the degree of defocusing of the image of the mask element on the target object to be positioned is determined, in particular minimized.
  • An essential core idea of the invention can be seen in the fact that the image of a mask element is projected onto the point within the effective volume of a focused laser beam, which is perceived as optimal for the experiment to be performed, so that this target object is located at a target object positioned in the focus environment of the laser beam serves as a projection surface for the image and thus on the basis of the sharpness or the degree of defocusing of the image of the mask element on the target object can be determined whether the target object is positioned at the optimum position in the effective volume or if there is still a shift of the target object or a change the distance between the focusing optics and the target object is needed to set this optimal position.
  • a target object can first be positioned (roughly) within the effective volume and then optimized in its position, which can be done to a highly accurate degree due to the determination of the degree of defocusing and the usually very short focal lengths of the focusing optics. It may be provided to observe the image of the mask object by a corresponding observation optics, so as to determine the degree of defocusing, which can be done both manually and more preferably automated.
  • the projection of the image of the mask element onto the target object which serves as a projection surface during the adjustment, is performed through the deflection optics which direct an incident laser beam or laser pulse onto the aforementioned focusing optics.
  • this deflection optics is highly reflective for the first, in particular pulsed, laser radiation used in the experiment, whereas it is transparent for a second wavelength, which is used for imaging the mask element is, in particular for a second laser radiation with a different laser wavelength.
  • dichroic mirrors can be used which have corresponding dielectric coatings.
  • the mirrors used highly reflective for this wavelength usually transitive for the visible wavelength range, so that here the proposed method or system no adjustment or change already existing optics required.
  • the focusing optics for the first laser radiation form part of the imaging optics for the mask element.
  • the imaging optics for the mask element is effected by two focusing optics, wherein one of the optics for imaging in the beam path in front of the deflection optics of the first, in particular pulsed laser radiation is arranged and the second focusing optics formed by the focusing optics of the first laser radiation is, so that in this sense, the imaging optics for the mask element image around the deflection optics in the beam path of the first, in particular pulsed laser radiation is arranged around.
  • the image of the mask element generated on the target object to be positioned is again imaged, namely here opposite the original imaging direction through the deflection optics into a second image plane, so that it is according to the invention may be provided, in this embodiment, not to determine the degree of defocusing directly on the target object, but in the second image plane and in particular to minimize.
  • an enlargement of the image of the mask element located on the target object can also be made so as to achieve a further simplified adjustment. This also makes it easier to automate the method since it is possible to position a detector, in particular a camera, in the second image plane and thus to enable an apparatus-supported examination of the degree of defocusing.
  • the beam path of the first laser radiation remains completely untouched even for this imaging measure.
  • the focusing optics for the first laser radiation is preferably used as part of the imaging optics for this second image, in particular as one of two focusing optics.
  • it can be provided to tilt the mask element at an angle to the optical axis of the second laser radiation, ie in particular at an angle not equal to 90 degrees, in particular to allow a sharp image of the mask element on a tilted to the optical axis of the first laser beam targets ,
  • certain (eg planar or planar) targets at an angle other than perpendicular (90 degrees) to the direction of incidence of the first laser beam into the effective volume can be taken into account, in particular around back reflections of the first laser beam from the target substrate into the first and / or second laser.
  • a respective tilted image plane is generated, so that it may be provided in this embodiment, the image plane of a detector, in particular a camera tilted at the same angle to the optical axis to order a sharp picture on the to preserve the entire picture plane.
  • the image plane of a detector in particular a camera tilted at the same angle to the optical axis to order a sharp picture on the to preserve the entire picture plane.
  • the target object have reached its optimum position in the effective volume, in particular focus of the first laser beam.
  • a contrast function is formed and evaluated from the detector signal, in particular thus from the camera image, in particular based on the gradient of the contrast function.
  • a clear maximum in the amount of the gradient can be determined, for example, it may be provided to position the target object where exactly the maximum is reached.
  • an electronic control system which evaluates the aforementioned detector signals and, in particular, formed gradients and thus drives an automatic positioning device for changing the distance between the focusing object and the target object.
  • the optimal position of the target object in the effective volume can also be automatically found by an iteration process, in particular taking into account the modulation transfer function of the entire imaging system.
  • the first image of the mask element on the target object may be provided to illuminate the mask element with a second laser radiation and thereby redirect the transmitted light of the mask element by means of a beam splitter and so Mask as shown by the deflection optics of the first laser radiation to the desired position in the effective volume, where as mentioned above, the imaging optics of two focusing optics and in particular the focusing optics of the first laser radiation form as one of these two optics.
  • the second image which may be provided according to the invention, into the second image plane for this further imaging to take place in transmission through this beam splitter. This ensures that the image in the second image plane is not returned to the mask itself, but the second image plane is separated from the object plane of the mask element.
  • the mask element is illuminated by means of collimated laser radiation, possibly after a previous widening by a telescope, since this makes it possible to obtain an afocal image of the mask element on the target object, ie it avoids that used to illuminate the mask element Laser beam is also focused on the target, so that in this way the known from the prior art problems influencing or destroying the target object by focused Justagestrahlung is completely avoided.
  • the two focusing optics of the imaging optics with the mask element and the image of the mask element in the effective volume forms a 4F optics configuration, in particular in the mask element and the image of the mask element in the effective volume are in mutually conjugate planes.
  • the two focusing optics of the imaging optics together with the image of the mask element in the effective volume and the image of the mask image in the second image plane, thus thus with the detector, which can be arranged in the second image plane, Forms a 4F optical configuration, in particular in which the image of the mask object in the effective volume and the detector are in mutually conjugate planes.
  • a positioning of the mask image in the effective volume at a desired position, ie in particular the optimal position of the focus of first laser radiation can be achieved by a shift of the mask, whereby the object plane of the mask changes in the imaging system and thus the image plane is shifted in the effective volume.
  • a possible detector such as a camera in the second image plane
  • it may be additionally provided behind the beam splitter mentioned above within the two imaging systems and the beam path in front of the deflection optics for the first laser beam to arrange an autocorrelation optics, with the mask image can be imaged directly into the second image plane, so that the optimal distance of the detector to the beam splitter and thus the optimal position in the second image plane can be adjusted by such a correlation optics first. Again, this can be done fully automatically according to the invention.
  • a target object such as metal or plastic foils in the focus of a laser pulse
  • a target object such as metal or plastic foils
  • a laser pulse for example a pico (10 12 ) or femto (10 15 ) Seconds of high energy laser pulses that can achieve more than 10 18 watts per square centimeter in the focus area.
  • the focus may be outside the geometric focal length of the focusing concave mirror used, e.g. is arranged due to noticeable non-linear properties, since the mask image can be adjusted at any desired position and deviating from the geometric focus.
  • the mask image can be placed in exactly this optimum position and used as an adjustment aid for future positioning of target objects, in particular in the context of an automated method.
  • the single figure shows in this embodiment of the method according to the invention a first beam path I, which is deflected with respect to the representation from above via a deflecting mirror 1 by approximately 90 degrees to the right.
  • the mirror 1 may be a dichroic mirror which is highly reflective for the wavelength of the laser used in the experiment and transmissive for an alignment laser beam.
  • Justagelasers can also be used in general, any other. Also not incoherent light source.
  • a focusing element 2 which is symbolically represented here and is usually formed in practice as a parabolic concave mirror follows.
  • These concave mirrors can especially with ultrashort pulses in the femtosecond range be specially designed to avoid a temporal pulse extension by dispersion effects of the dielectric coatings.
  • a focus 3 is generated by the focusing element 2 in particular a parabolic concave mirror in the beam path 1, around the center of which an effective volume is formed, in which a target object 4 must be accurately positioned to carry out an experiment.
  • the image of a mask element 5 by an imaging optics, which is formed by a focusing optics 6, for example a first lens or a first concave mirror, and the focusing optics 2.
  • the mask element 5 by means of a telescopically arranged in particular focusing elements 7 and 8, in particular lenses, with a laser beam of a second wavelength for which the deflection mirror 1 is transmissive.
  • the laser beam is both expanded and collimated, so that between 4 masking element, focusing element 6, focusing element 2 and the image of the mask element 3 results in a 4F configuration and thus a telecentric afocal image, which means in that an image of the mask 5 is produced at the position P, while the collimation, ie the parallel beam path of the laser beam of the second wavelength is maintained and thereby no destructive increase in intensity of the laser beam of the second wavelength takes place on the target.
  • the light emanating from the mask element 5 by a second beam path Il which is deflected by a beam splitter 9 and coincides after passing through the deflecting element 1 with the beam path I of the first laser beam.
  • the light of the mask image backscattered by the target object passes through the beam splitter 9, so that the image does not fall back on itself and thus the second image can be used for evaluation by means of a detector.
  • the focusing optics 6 and 2 are used as the imaging system, the focusing optics 2 coinciding with the focusing optics in the beam path 1 of the experimental laser beam.
  • an inventive adjustment system can also be used later on an existing experimental arrangement without having to make an intervention in the arrangement.
  • an autocorrelation optics 10 which is not shown here and which reflects back a portion of the light emanating from the mask element 5 which has passed through the beam splitter 9, that is to say by the reflection at the beam splitter 9 an immediate mapping of the mask element into the image plane B can take place.
  • an optimal adjustment of the detector in the image plane B can first be carried out for carrying out the method according to the invention.
  • Sources of error due to misadjustments of the detector within the image plane B, which would affect an unsatisfactory positioning of the target object, can thus be avoided be, because it is thus initially made sure that the adjustment aid system is optimally adjusted in itself.

Landscapes

  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Laser Beam Processing (AREA)

Abstract

L'invention concerne un procédé et un système de positionnement reproductible d'un objet cible dans le volume d'action d'un premier faisceau laser, en particulier un faisceau laser à impulsions, qui après un système optique déflecteur (1), lequel est hautement réfléchissant pour les longueurs d'onde du premier faisceau laser (I) et laisse passer au moins une seconde longueur d'onde, en particulier un second faisceau laser (II), peut être mis au point à l'aide d'un système optique de focalisation (2) dans le volume d'action, caractérisé en ce que à la position souhaitée (P), la reproduction d'un élément de masque (5) d'un objet cible (4) à positionner dans le volume d'action est projetée par le système optique déflecteur (1) à l'aide d'un second faisceau laser et le degré de la défocalisation de la reproduction de l'objet cible (4) à positionner est déterminé, en particulier minimisé.
PCT/EP2008/002956 2007-04-16 2008-04-14 Procédé et système de positionnement reproductible d'un objet cible dans le volume d'action d'un faisceau laser WO2008125327A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102007018140.1 2007-04-16
DE102007018140A DE102007018140A1 (de) 2007-04-16 2007-04-16 Verfahren und System zur reproduzierbaren Positionierung eines Zielobjektes in das Wirkvolumen einer Laserstrahlung

Publications (1)

Publication Number Publication Date
WO2008125327A1 true WO2008125327A1 (fr) 2008-10-23

Family

ID=39579981

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2008/002956 WO2008125327A1 (fr) 2007-04-16 2008-04-14 Procédé et système de positionnement reproductible d'un objet cible dans le volume d'action d'un faisceau laser

Country Status (2)

Country Link
DE (1) DE102007018140A1 (fr)
WO (1) WO2008125327A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19520213A1 (de) * 1994-06-02 1995-12-07 Mitsubishi Electric Corp Verfahren und Vorrichtung zum optischen Bearbeiten von Werkstücken
WO2000021475A1 (fr) * 1998-10-14 2000-04-20 Irvision, Inc. Appareil et procede destines a projeter un motif de reference dans le champ de vision d'un systeme optique
US6099522A (en) * 1989-02-06 2000-08-08 Visx Inc. Automated laser workstation for high precision surgical and industrial interventions
US20030183744A1 (en) * 2002-03-29 2003-10-02 Marc Nantel Autofocus feedback positioning system for laser processing
US20060019503A1 (en) * 2004-07-22 2006-01-26 Yoshio Takami Laser crystallization apparatus and laser crystallization method

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10250012B4 (de) * 2002-10-25 2005-06-23 Universität Kassel Verfahren zur Bestimmung der Oberflächenstruktur einer Materialprobe mit ultrakurzen Laserpulsen und Vorrichtung zur Durchführung des Verfahrens
US20050191771A1 (en) * 2004-03-01 2005-09-01 Ming Li Ultrafast laser direct writing method for modifying existing microstructures on a submicron scale
US20060007554A1 (en) * 2004-07-08 2006-01-12 Joerg Ferber Method and apparatus for maintaining focus and magnification of a projected image
US7366378B2 (en) * 2004-10-29 2008-04-29 Matsushita Electric Industrial Co., Ltd. Ultrafast laser machining system and method for forming diffractive structures in optical fibers

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6099522A (en) * 1989-02-06 2000-08-08 Visx Inc. Automated laser workstation for high precision surgical and industrial interventions
DE19520213A1 (de) * 1994-06-02 1995-12-07 Mitsubishi Electric Corp Verfahren und Vorrichtung zum optischen Bearbeiten von Werkstücken
WO2000021475A1 (fr) * 1998-10-14 2000-04-20 Irvision, Inc. Appareil et procede destines a projeter un motif de reference dans le champ de vision d'un systeme optique
US20030183744A1 (en) * 2002-03-29 2003-10-02 Marc Nantel Autofocus feedback positioning system for laser processing
US20060019503A1 (en) * 2004-07-22 2006-01-26 Yoshio Takami Laser crystallization apparatus and laser crystallization method

Also Published As

Publication number Publication date
DE102007018140A1 (de) 2008-10-23

Similar Documents

Publication Publication Date Title
DE102015001421B4 (de) Vorrichtung und Verfahren zur Strahldiagnose an Laserbearbeitungs-Optiken (PRl-2015-001)
DE112007000128B4 (de) Vorrichtung zur Bestimmung einer Zielposition eines geladenen Teilchenstrahls, Verfahren zur Verwendung der Vorrichtung und Bahandlungsvorrichtung, die die Vorrichtung zur Bestimmung einer Zielposition verwendet
EP0168351B1 (fr) Générateur laser de motifs et procédé pour son emploi
DE102012022039B4 (de) Modulare Laserbestrahlungseinheit
EP3100011B1 (fr) Caméra à propagation de faisceaux et procédé d'analyse de faisceaux lumineux
DE102012212354B4 (de) Messvorrichtung zur Vermessung und Überwachung mindestens eines Laserstrahls, Strahlführungssystem zur Führung mindestens eines Laserstrahls mit einer derartigen Messvorrichtung sowie Verwendung einer derartigen Messvorrichtung
DE102021101164A1 (de) Verfahren und Vorrichtung zum Herstellen eines dreidimensionalen Objekts in einem optisch reaktiven Ausgangsmaterial
DE102007003777B4 (de) Messvorrichtung und Verfahren zur optischen Vermessung eines Objektes
EP3140628B1 (fr) Système et procédé d'analyse d'un faisceau lumineux guidé par une optique de guidage de faisceau
EP3152983A1 (fr) Dispositif et procédé de surveillance d'un faisceau laser
DE102010027720A1 (de) Verfahren und Vorrichtungen zur Positions- und Kraftdetektion
EP2621662B1 (fr) Dispositif et procédé pour le traitement d'une matière au moyen d'un rayonnement électromagnétique focalisé
DE4446185C2 (de) Vorrichtung zum Einkoppeln eines UV-Laserstrahls in ein konfokales Laser-Scanmikroskop
DE102011016058A1 (de) Verfahren und Vorrichtung zur Einstellung von Eigenschaften eines Strahlenbündels aus einem Plasma emittierter hochenergetischer Strahlung
EP4360853A1 (fr) Procédé et appareil de traitement d'un matériau optiquement réactif
DE102015219330A1 (de) Verfahren und Vorrichtung zur Strahlanalyse
DE102012218920A1 (de) Vorrichtung zur Beleuchtung einer Probe
WO2008125327A1 (fr) Procédé et système de positionnement reproductible d'un objet cible dans le volume d'action d'un faisceau laser
WO2012143070A1 (fr) Procédé de fabrication d'un guide d'ondes dans un polymère
DE102012219169B4 (de) Strahlregelungsvorrichtung für einen Beleuchtungsstrahl, optisches System mit einer derartigen Strahlregelungsvorrichung sowie Metrologiesystem mit einem eine solche Strahlregelungsvorrichtung enthaltenden optischen System
WO2020030410A1 (fr) Installation d'éclairage pour un microscope, microscope et procédé d'éclairage d'un volume d'échantillon dans un microscope
EP2767797A1 (fr) Interféromètre ä faible cohérence et procédé de mesure optique à résolution spatiale du profil de surface d'un objet
WO2019137642A1 (fr) Procédé et dispositif de suivi optique de cible d'un objet cible pouvant être irradié par un laser à haute énergie
DE102005056404B4 (de) Röntgenmikroskop mit Kondensor-Monochromator-Anordnung hoher spektraler Auflösung
WO2024017829A1 (fr) Dispositif de mesure pour ajuster un faisceau laser

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 08735231

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 08735231

Country of ref document: EP

Kind code of ref document: A1