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DE4310023A1 - Q-switched long-pulse solid-state laser having fibre-optic resonator extension - Google Patents

Q-switched long-pulse solid-state laser having fibre-optic resonator extension

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Publication number
DE4310023A1
DE4310023A1 DE19934310023 DE4310023A DE4310023A1 DE 4310023 A1 DE4310023 A1 DE 4310023A1 DE 19934310023 DE19934310023 DE 19934310023 DE 4310023 A DE4310023 A DE 4310023A DE 4310023 A1 DE4310023 A1 DE 4310023A1
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Prior art keywords
state laser
long
pulse
laser system
pulse solid
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DE19934310023
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German (de)
Inventor
Gerhard Prof Dr Ing Mueller
Pavel Prof Pashinin
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LASER MEDIZIN ZENTRUM GGMBH BE
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LASER MEDIZIN ZENTRUM GGMBH BE
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Priority to DE19934310023 priority Critical patent/DE4310023A1/en
Priority to DE4336947A priority patent/DE4336947A1/en
Priority to EP94911094A priority patent/EP0691043B1/en
Priority to AT94911094T priority patent/ATE155617T1/en
Priority to DE59403398T priority patent/DE59403398D1/en
Priority to PCT/DE1994/000362 priority patent/WO1994023478A2/en
Publication of DE4310023A1 publication Critical patent/DE4310023A1/en
Priority to US08/968,765 priority patent/US5963575A/en
Withdrawn legal-status Critical Current

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/18—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves
    • A61B18/20—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser
    • A61B18/22—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor
    • A61B18/26—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor for producing a shock wave, e.g. laser lithotripsy
    • 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
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • 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
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/081—Construction or shape of optical resonators or components thereof comprising three or more reflectors
    • 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
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • 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
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/106—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity
    • H01S3/108—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity using non-linear optical devices, e.g. exhibiting Brillouin or Raman scattering
    • H01S3/109—Frequency multiplication, e.g. harmonic generation
    • 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
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/11—Mode locking; Q-switching; Other giant-pulse techniques, e.g. cavity dumping
    • H01S3/1123—Q-switching
    • H01S3/113—Q-switching using intracavity saturable absorbers
    • 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
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/08013—Resonator comprising a fibre, e.g. for modifying dispersion or repetition rate

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Health & Medical Sciences (AREA)
  • Surgery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biomedical Technology (AREA)
  • Otolaryngology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Heart & Thoracic Surgery (AREA)
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  • General Health & Medical Sciences (AREA)
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  • Nonlinear Science (AREA)
  • Lasers (AREA)

Abstract

Q-switched long-pulse solid-state laser for laser-lithotripsy, pulse-lengthening being achieved by extending the laser resonator by means of an optical waveguide, with use of a passive Q-switch.

Description

AufgabenstellungTask

Insbesondere für die Laserlithotripsie soll ein kompakter kostengünstig herstellbarer Laser ent­ wickelt werden, der die Nachteile bisher bekannter und marktgängiger Systeme im Hinblick auf Effi­ zienz und Herstellkosten vermeidet.In particular for laser lithotripsy, a compact, inexpensive to produce laser ent be wound, the disadvantages known so far and marketable systems with regard to Effi avoids ciency and manufacturing costs.

Stand der TechnikState of the art

Aus den Druckschriften WO 90/12544, WO 90/04358, WO 91/05332 und AT-B-380634 sind Festkörperlasersysteme für die Laserlitho­ tripsie bekannt. Diese Systeme weisen jedoch den Nachteil auf, daß aufgrund der dort verfügbaren kurzen Pulslängen die Energie übertragende Faser sich im praktischen Gebrauch sehr schnell selbst zerstört. Darüber hinaus sind die technischen Auf­ bauten derartiger Lasersysteme sehr kostenintensiv und auch sehr serviceanfällig. Auf der anderen Seite hat es sich als günstig herausgestellt, mit einem sogenannten Doppelpuls zu arbeiten, bei dem der eine Puls zum eigentlichen energietragen­ den Puls blau verschoben ist, typischerweise die Harmonische der Grundwellenlänge darstellt. Diese Kombination erlaubt ein frühzeitiges Zünden des optischen Durchbruchs (Plasma) an der zu zer­ störenden Steinoberfläche und ermöglichen damit einen höheren Wirkungsgrad bei der Steinzer­ trümmerung. Allerdings zeigen auch diese soge­ nannten Doppelpulssysteme den Nachteil eines schnellen Faserabbrandes beim praktischen Ein­ satz. From the publications WO 90/12544, WO 90/04358, WO 91/05332 and AT-B-380634 are solid state laser systems for laser litho tripsie known. However, these systems have the Disadvantage on that due to the availability there short pulse lengths the energy-transmitting fiber very quickly in practical use destroyed. In addition, the technical up built such laser systems very costly and also very service-sensitive. On the other Side it turned out to be cheap with to work with a so-called double pulse at which the one pulse carried to the actual energy the pulse is shifted blue, typically that Represents harmonic of the fundamental wavelength. This combination allows early ignition of the optical breakthrough (plasma) on the zer disruptive stone surface and thus allow a higher efficiency at the Steinzer debris. However, these so-called called double pulse systems the disadvantage of one fast fiber burn-up during practical on sentence.  

Erfindungsgemäße LösungSolution according to the invention

Ausgehend von dem bekannten Stand der Technik hat sich überraschenderweise gezeigt, daß die Effi­ zienz der Steinzertrümmerung nicht nur vom frühestmöglichen Zünden eines Plasmas und der dadurch entstehenden Stoßwelle und der Erzeu­ gung von Kavitationsblasen abhängt, sondern ent­ scheidend durch die Erzeugung einer Einschluß­ bedingung für das Plasma mit nachfolgendem Ver­ dichtungsstoß bestimmt ist. Theoretische und expe­ rimentelle Untersuchungen der Erfinder konnten überraschenderweise bestätigen, daß optimale Ein­ schlußbedingungen unter Berücksichtigung der Laufzeit der akustischen Stoßwellen durch die Geometrie der energieapplizierenden Endfläche der Faser selbst gegeben sind. Als Faustregel wurde gefunden, daß die Pulsdauer für die optimale Ein­ schlußbedingung in Nanosekunden dem 1,5fachen des Durchmessers der energieapplizierenden Fasern in Mikrometern entspricht. Das heißt also beispielsweise, bei einer Q/Q-Faser mit 360 µm Kern, die einen Durchmesser am optischen Cladding von etwa 400 bis 420 µm besitzt - je nach Hersteller - ist die optimale Pulsdauer für die Lithotripsie ca. 600 bis 650 ns. Damit stellt sich als zweiter Schritt der erfinderischen Aufgabe die Entwicklung eines Festkörperlasersystems nach dem Doppelpulsverfahren mit einer Pulslänge, die je nach verwendeter Applikationsfaser zwischen 200 ns und 1 µs variiert werden kann. Gleichzeitig soll dieses Festkörperlasersystem möglichst kosten­ günstig herstellbar sein. Aus Kostengründen kom­ men daher nur neodymdotierte Laserkristalle, wie Nd:YAG und Nd:YAlO3 in Betracht, obwohl das Prinzip der erfindungsgemäßen Lösung auch auf jedes andere laseraktive Material zutrifft. Nd:YAG- oder Nd:YAlO3-Laserkristalle haben im normalen gütegeschalteten Betrieb allerdings lediglich Pulslängen zwischen 7 und 15 ns. Erfindungsgemäß wird diese Limitierung durch eine optische Verlängerung des Resonators mittels eines langen, zu einer Spule aufgewickelten optischen Wellenleiters überwunden. Für die als optimal erkannten Pulslängen von ca. 650 ns ist typischerweise eine Resonatorverlängerung mittels eines optischen Wellenleiters von ca. 18 cm Länge notwendig. Dabei ist erfindungswesentlich, daß durch die Einführung der Resonatorverlängerung mittels eines optischen Lichtwellenleiters - typischerweise einer Q/Q-Faser - nicht nur die Pulslänge des Lasersystems in weiten Bereichen in Abhängigkeit von der Faserlänge veränderbar ist - typischerweise zwischen 200 ns und 1 µs - ohne daß sich die abgegebene Pulsspitzenleistung wesentlich ändert (Variationen < 10%), sondern daß gleichzeitig durch den optischen Wellenleiter eine Glättung der sonst störenden Intensitäts­ oszillationen während eines Laserpulses erreicht wird. Diese Intensitätsoszillationen, sog. Spiking, trägt wesentlich mit zur Zerstörung der energieapplizierenden Faser bei, so daß durch die erfindungsgemäße Konstruktion eines gütegeschal­ teten Langpulslasers, wie in den nachstehenden Abbildungen einzeln beschrieben, neben der kostengünstigen Realisierung des langen gütege­ schalteten Pulses selbst, auch eine Glättung des zeitlichen Pulsprofils stattfindet.Based on the known prior art, it has surprisingly been found that the effi ciency of stone crushing depends not only on the earliest possible ignition of a plasma and the resulting shock wave and the generation of cavitation bubbles, but crucially by generating an inclusion condition for the plasma is determined with subsequent shock. Theoretical and experimental investigations by the inventors were able to surprisingly confirm that optimal conditions are given, taking into account the propagation time of the acoustic shock waves, by the geometry of the energy-applying end face of the fiber itself. As a rule of thumb, it was found that the pulse duration for the optimal closing condition in nanoseconds corresponds to 1.5 times the diameter of the energy-applying fibers in micrometers. For example, for a Q / Q fiber with a 360 µm core that has a diameter of around 400 to 420 µm on the optical cladding - depending on the manufacturer - the optimal pulse duration for lithotripsy is approximately 600 to 650 ns. This is the second step in the inventive task of developing a solid-state laser system using the double-pulse method with a pulse length that can be varied between 200 ns and 1 μs depending on the application fiber used. At the same time, this solid-state laser system should be inexpensive to manufacture. For cost reasons, therefore, only neodymium-doped laser crystals such as Nd: YAG and Nd: YAlO 3 come into consideration, although the principle of the solution according to the invention also applies to any other laser-active material. Nd: YAG or Nd: YAlO 3 laser crystals only have pulse lengths between 7 and 15 ns in normal Q-switched operation. According to the invention, this limitation is overcome by an optical extension of the resonator by means of a long optical waveguide wound into a coil. For the pulse lengths of approx. 650 ns recognized as optimal, a resonator extension using an optical waveguide of approx. 18 cm length is typically necessary. It is essential to the invention that by introducing the resonator extension by means of an optical fiber - typically a Q / Q fiber - not only the pulse length of the laser system can be varied over a wide range depending on the fiber length - typically between 200 ns and 1 μs - without the delivered pulse peak power changes significantly (variations <10%), but that at the same time a smoothing of the otherwise disturbing intensity oscillations during a laser pulse is achieved by the optical waveguide. This intensity oscillation, so-called spiking, contributes significantly to the destruction of the energy-applying fiber, so that the inventive construction of a quality-switched long pulse laser, as described individually in the figures below, in addition to the cost-effective realization of the long quality-switched pulse itself, also a smoothing of the temporal pulse profile takes place.

In einer bevorzugten Ausführungsform besteht sodann ein erfindungsgemäßer gütegeschalteter Langpuls-Festkörperlaser für die Lithotripsie lediglich noch aus drei vorjustierbaren Baugruppen, die in Abb. 1 näher erläutert sind.In a preferred embodiment, a Q-switched long-pulse solid-state laser for lithotripsy according to the invention then only consists of three pre-adjustable modules, which are explained in more detail in FIG. 1.

Abb. 1 zeigt eine bevorzugte optische Anordnung für einen Langpuls-Festkörperlithotripsielaser. Dabei besteht die Baugruppe 1 aus einer Fokussierlinse (1.3) der faseroptischen Resonator­ verlängerung (1.2) und einem gewölbten Resona­ torendspiegel (1.1), dessen Wölbung und Abstand zum Faseraustritt der Resonatorverlängerung (1.2) derart bemessen ist, daß unter Berücksichtigung der numerischen Apertur der Faser der Krümmungsradius etwa dem halben Abstand zwischen Faserendfläche und Spiegeloberfläche entspricht. Fig. 1 shows a preferred optical arrangement for a long-pulse solid-state lithotripsy laser. In this case, 1 the assembly consists of a focusing lens (1.3) of the fiber optic resonator extension (1.2) and a domed resonators torendspiegel (1.1), the curvature and spacing is measured at the fiber exit of the resonator extension (1.2) such that in consideration of the numerical aperture of the fiber the radius of curvature corresponds to approximately half the distance between the fiber end face and the mirror surface.

Die Baugruppe 2 beinhaltet eine Laserkavität nach dem Stand der Technik. Dabei entspricht (2.1) dem Laserkristall, vorzugsweise Nd:YAG oder Nd:YAlO3, (2.2) der Blitzlampe zum optischen Pumpen und (2.3) der Energieversorgung und Systemsteuerung.The assembly 2 contains a laser cavity according to the prior art. ( 2.1 ) corresponds to the laser crystal, preferably Nd: YAG or Nd: YAlO 3 , ( 2.2 ) the flash lamp for optical pumping and ( 2.3 ) the energy supply and system control.

Die Baugruppe 3 beinhaltet den teiltransparenten Resonator Endspiegel (3.4), einen nichtlinearen Kristall zur Frequenzverdopplung, typischerweise einen KTP-Kristall (3.3), sowie einen passiven Güteschalter, typischerweise Cr4+:YAG bzw. LiF(F2-) und einer Relaisoptik (3.1) zur Kollimie­ rung der Strahlung.The assembly 3 contains the partially transparent resonator end mirror ( 3.4 ), a nonlinear crystal for frequency doubling, typically a KTP crystal ( 3.3 ), and a passive Q-switch, typically Cr 4+ : YAG or LiF (F 2- ) and a relay optics ( 3.1 ) for collimating the radiation.

In Weiterführung des Erfindungsgedankens kann durch Einfügen einer polarisationsoptischen Bau­ gruppe, bestehend aus einem Brewster-Winkel­ polarisator und einem im wesentlichen rechtwinklig hierzu angeordneten Retroreflektor, zwischen ent­ weder den Bauelementen 1.2 und 1.3 der Bau­ gruppe 1 oder den Bauelementen 3.2 und 3.3 der Baugruppe 3 eine weitere Steigerung der Effizienz zur Erzeugung der ersten Harmonischen erreicht werden. Für das bevorzugte Ausführungsbeispiel lassen sich ausgehend von einem neodymdotierten YAG-Laserkristall von 5 mm Durchmesser und 5 cm Länge, bei einer Pumpenergie an der Blitz­ lampe von ca. 30 J folgende typische Ausgangs­ werte erreichen:In continuation of the inventive concept, by inserting a polarization-optical construction group consisting of a Brewster angle polarizer and a retroreflector arranged essentially at right angles thereto, between either the components 1.2 and 1.3 of the construction group 1 or the components 3.2 and 3.3 of the assembly 3 one further increase in efficiency for generating the first harmonics can be achieved. For the preferred embodiment, starting from a neodymium-doped YAG laser crystal of 5 mm in diameter and 5 cm in length, with a pump energy on the flash lamp of approx. 30 J, the following typical initial values can be achieved:

Pulsdauer, einstellbar zwischen 200 ns und 1 µs, abhängig von der Länge der Faserverlängerung im Resonator, bei ca. 20 m Faserlänge 160 mJ bei 1064 nm Grundemission und ca. 15 mJ bei 532 nm (2. Harmonische), ausgehend von einer Grundab­ sorption des passiven Güteschalters von ca. 25%. Dabei ändert sich bei Variationen der Pulslänge von 200 ns bis 1 µs die Ausgangsenergie lediglich um ca. 10%. Bei Verwendung von polarisierter Laserstrahlung, entweder durch Hinzufügen der erfindungsgemäßen zusätzlichen Baugruppe oder durch Verwendung eines doppelbrechenden Lasermaterials, wie beispielsweise Nd:YAlO3, erhöht sich die Ausgangsenergie der 2 Harmo­ nischen auf ca. 22 bis 25 mJ. Dabei beträgt der Kerndurchmesser der Resonatorverlängerung lediglich 280 µm, so daß unter Berücksichtigung der durch die numerische Apertur bedingten Divergenz die Übertragung der gesamt abgegebenen Energie durch eine 360 µm Kerndurchmesser Q/Q-Faser (4) zur Lithotripsie möglich ist.Pulse duration, adjustable between 200 ns and 1 µs, depending on the length of the fiber extension in the resonator, with approx. 20 m fiber length 160 mJ at 1064 nm basic emission and approx. 15 mJ at 532 nm (2nd harmonic), starting from a basic absorption of the passive Q-switch of approx. 25%. When the pulse length varies from 200 ns to 1 µs, the output energy only changes by approx. 10%. When using polarized laser radiation, either by adding the additional assembly according to the invention or by using a birefringent laser material, such as Nd: YAlO 3 , the output energy of the 2 harmonics increases to approx. 22 to 25 mJ. The core diameter of the resonator extension is only 280 µm, so that taking into account the divergence caused by the numerical aperture, the transfer of the total energy released through a 360 µm core diameter Q / Q fiber ( 4 ) for lithotripsy is possible.

Erfindungsgemäß wird eine weitere Steigerung der Zerstörungseffizienz zur Lithotripsie dadurch erreicht, daß der Laserkristall mit einer höheren als zur Erzeugung von Einzelpulsen notwendigen Pumpenergie angeregt wird. Bereits die Erhöhung um 30%, also auf ca. 40 J, hat die Emission einer Kaskade von Einzelimpulsen zur Folge, deren zeit­ licher Abstand bei einer Grundabsorption des Güteschalters von 25% bei ca. 50 µs liegt und deren zeitlicher Abstand bei Erhöhung der Grundabsorption um den Faktor 2 etwa halbiert werden kann. Diese Impulskaskade (auch Burst) genannt, führt zu einer wesentlichen Steigerung der Zerstörungseffizienz am Stein (5) bei der Lithotripsie, da durch die optimierten Einschlußbedingungen die Folgepulse unmittelbar zur Erzeugung von sequentiellen Verdichtungsstößen genutzt werden können.According to the invention, a further increase in the destruction efficiency for lithotripsy is achieved in that the laser crystal is excited with a pump energy that is higher than that required to generate individual pulses. Already the increase by 30%, i.e. to approx. 40 J, results in the emission of a cascade of individual pulses, the time interval of which is about 50 µs with a basic absorption of the Q-switch and about 50 µs and the time interval when the basic absorption is increased can be roughly halved by a factor of 2. This pulse cascade (also called burst) leads to a significant increase in the destruction efficiency of the stone ( 5 ) in lithotripsy, since the subsequent pulses can be used directly to generate sequential compression shocks due to the optimized inclusion conditions.

Claims (10)

1. Gütegeschalteter Langpuls-Festkörperlaser für die Laserlithotripsie, dadurch gekennzeichnet, daß bei Verwendung eines passiven Güteschalters eine Pulsverlängerung durch eine Verlänge­ rung des Laseresonators mittels eines optischen Wellenleiters erreicht wird.1. Q-switched long-pulse solid-state laser for laser lithotripsy, characterized in that when using a passive Q-switch a pulse extension is achieved by an extension of the laser resonator by means of an optical waveguide. 2. Langpuls-Festkörperlasersystem nach 1, dadurch gekennzeichnet, daß zur Effizienzsteigerung der Güteschaltung und der Frequenzverdopplung eine konfokale Anordnung, bestehend aus einer Kollima­ tionslinse und einem teildurchlässigen Konkavspiegel aufgebaut ist, wobei in der Strahltaille des Systems der passive Güte­ schalter und der Verdopplerkristall angeord­ net sind.2. long pulse solid-state laser system according to 1, characterized in that to increase the efficiency of the quality switch and frequency doubling a confocal Arrangement consisting of a collima tion lens and a partially permeable Concave mirror is built, being in the Beam waist of the passive goodness system switch and the doubler crystal arranged are not. 3. Langpuls-Festkörperlasersystem nach 1 und 2, dadurch gekennzeichnet, daß die Pulslänge durch Wahl der faseroptischen Resonatorverlängerung zwischen 0,2 und 1 µs wählbar ist. 3. long pulse solid-state laser system according to 1 and 2, characterized in that the pulse length by choosing the fiber optic Resonator extension between 0.2 and 1 µs is selectable.   4. Langpuls-Festkörperlasersystem nach 1 bis 3, dadurch gekennzeichnet, daß zur faseroptischen Resonatorverlängerung eine Q/Q-Faser mit einer numerischen Aper­ tur von ca. 0,2 verwendet wird.4. long pulse solid-state laser system according to 1 to 3, characterized in that for fiber optic resonator extension a Q / Q fiber with a numerical aper of about 0.2 is used. 5. Langpuls-Festkörperlasersystem nach 1 bis 4, dadurch gekennzeichnet, daß die Resonatorverlängerung als eine Bau­ gruppe bestehend aus einer abberrations­ armen Kollimationslinse (1.3), einer Faser­ wicklung geeigneter Länge (1.2) und einem konkaven Retroreflektor (1.1) besteht.5. long-pulse solid-state laser system according to 1 to 4, characterized in that the resonator extension as a construction group consisting of a low-aberration collimation lens ( 1.3 ), a fiber winding of suitable length ( 1.2 ) and a concave retroreflector ( 1.1 ). 6. Langpuls-Festkörperlasersystem nach 1 bis 5, dadurch gekennzeichnet, daß die Resonatorstruktur aus drei jeweils für sich vorjustierten und einfach montierbaren Kom­ ponenten besteht.6. long pulse solid-state laser system according to 1 to 5, characterized in that the resonator structure of three each for itself pre-adjusted and easy to install com components. 7. Langpuls-Festkörperlasersystem nach 1 bis 6, dadurch gekennzeichnet, daß die Baugruppe 2 eine einstellbare Pumpener­ gie zwischen 30 und 50 J und damit gekoppelt eine Anzeige, die das Auftreten von Kaska­ denimpulsen zur Verfügung stellt. 7. long-pulse solid-state laser system according to 1 to 6, characterized in that the assembly 2 an adjustable pump energy between 30 and 50 J and coupled with it a display that provides the occurrence of Kaska denimpulsen. 8. Langpuls-Festkörperlasersystem nach 1 bis 7, dadurch gekennzeichnet, daß als laseraktives Medium Nd:YAG oder Alexandrit oder Titansaphir verwendet wird.8. long pulse solid-state laser system according to 1 to 7, characterized in that as laser active medium Nd: YAG or Alexandrite or titanium sapphire is used. 9. Langpuls-Festkörperlasersystem nach 1 bis 8, dadurch gekennzeichnet, daß als laseraktives Medium ein doppelbrechen­ der Kristall, wie z. B. Nd:YAlO3 oder Nd:YLF verwendet wird.9. long-pulse solid-state laser system according to 1 to 8, characterized in that a double refraction of the crystal, such as. B. Nd: YAlO 3 or Nd: YLF is used. 10. Langpuls-Festkörperlasersystem nach 1 bis 9, dadurch gekennzeichnet, daß zusätzliche Maßnahmen zur Erzeugung pola­ risierter Strahlung in den Baugruppen 1 bzw. 3 durch Einfügen eines Polarisationsstrahl­ teilers und eines Retroreflektors vorgesehen sind.10. Long-pulse solid-state laser system according to 1 to 9, characterized in that additional measures for generating polarized radiation in the modules 1 and 3 are provided by inserting a polarization beam splitter and a retroreflector.
DE19934310023 1993-03-27 1993-03-27 Q-switched long-pulse solid-state laser having fibre-optic resonator extension Withdrawn DE4310023A1 (en)

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DE19934310023 DE4310023A1 (en) 1993-03-27 1993-03-27 Q-switched long-pulse solid-state laser having fibre-optic resonator extension
DE4336947A DE4336947A1 (en) 1993-03-27 1993-10-29 Long pulse laser with resonator extension using an optical waveguide
EP94911094A EP0691043B1 (en) 1993-03-27 1994-03-28 Q-switched laser system, in particular for laser lithotripsy
AT94911094T ATE155617T1 (en) 1993-03-27 1994-03-28 QUALITY SWITCHED LASER SYSTEM, ESPECIALLY FOR LASER LITHOTRIPSY
DE59403398T DE59403398D1 (en) 1993-03-27 1994-03-28 QUALITY SWITCHED LASER SYSTEM, ESPECIALLY FOR LASER LITHOTRIPSY
PCT/DE1994/000362 WO1994023478A2 (en) 1993-03-27 1994-03-28 Q-switched laser system, in particular for laser lithotripsy
US08/968,765 US5963575A (en) 1993-03-27 1997-09-22 Q-switched laser system, in particular for laser lithotripsy

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EP3711819A4 (en) * 2018-11-20 2021-03-17 Jilin Province King Laser Co., Ltd. ELECTRO-OPTIC DOUBLE FREQUENCY AND DOUBLE PULSE LASER LITHOTRIPSY SYSTEM WITH QUALITY SWITCH

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DE19958566A1 (en) * 1999-12-04 2001-06-07 Zeiss Carl Jena Gmbh Q-switched solid state laser with adjustable pulse length has acousto-optical Q-switch controlled by controlling gradient of edges of modulation function of high frequency wave
WO2002029941A3 (en) * 2000-10-03 2002-11-21 Clyxon Laser Gmbh Devices for varying the pulse duration and/or pulse energy in a passively q-switched laser
EP3711819A4 (en) * 2018-11-20 2021-03-17 Jilin Province King Laser Co., Ltd. ELECTRO-OPTIC DOUBLE FREQUENCY AND DOUBLE PULSE LASER LITHOTRIPSY SYSTEM WITH QUALITY SWITCH
US11364078B2 (en) 2018-11-20 2022-06-21 Jilin Province King Laser Co., Ltd. Electro-optic Q-switching double-frequency double-pulse laser lithotripsy system

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