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WO1990013157A1 - LASERS A SEMICONDUCTEURS Nd:YLF MULTIKILOWATT - Google Patents

LASERS A SEMICONDUCTEURS Nd:YLF MULTIKILOWATT Download PDF

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Publication number
WO1990013157A1
WO1990013157A1 PCT/US1990/002210 US9002210W WO9013157A1 WO 1990013157 A1 WO1990013157 A1 WO 1990013157A1 US 9002210 W US9002210 W US 9002210W WO 9013157 A1 WO9013157 A1 WO 9013157A1
Authority
WO
WIPO (PCT)
Prior art keywords
laser
rods
resonator
lens
solid state
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.)
Ceased
Application number
PCT/US1990/002210
Other languages
English (en)
Inventor
Kuo-Ching Liu
Sten Tornegard
Michael Rhoades
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Quantronix Inc
Original Assignee
Quantronix Inc
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 Quantronix Inc filed Critical Quantronix Inc
Publication of WO1990013157A1 publication Critical patent/WO1990013157A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • H01S3/07—Construction or shape of active medium consisting of a plurality of parts, e.g. segments
    • 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
    • H01S3/08072—Thermal lensing or thermally induced birefringence; Compensation thereof

Definitions

  • the present invention relates to solid-state lasers and, more particularly, to improvements in solid state lasers having low thermal focusing and low thermal birefringence loss.
  • High power TEM 00 solid-state laser output is required for many commercial or research and development applications.
  • Large active mode volume in the solid-state lasing crystal is a critical requirement in achieving this goal.
  • the active lasing volume in Nd-doped YAG (the most popular solid-state laser host) has been limited by its thermally-induced focusing (caused by large refractive index variation with temperature) and by thermal birefringence loss which increases quadratically with radial position in cylindrical laser rods. Therefore, CW TEM 00 power over 30 watts remains unavailable from any commercial solid- state laser system today.
  • Nd:LiYF 4 YLF
  • This crystal has very low thermal focusing and, because it is a birefringent crystal, its lasing output is naturally polarized and hence unaffected by thermal birefringence loss.
  • Nd:YLF lasers have achieved TEM 00 power outputs comparable to Nd:YAG with equivalent sized rods.
  • Thermal focusing in Nd:YLF Laser rods although small, nevertheless is astigmatic, i.e. its magnitude and sign are different in the X and Y directions. This is conventionally corrected by utilizing a cylindrical lens to produce an output beam that is circularly symmetrical. This cylindrical lens is in addition to the spherical lens used to expand the beam for large mode volume.
  • An object of the present invention is to increase the TEM 00 power output of solid state lasers having low thermal focusing and low thermal birefringence loss.
  • a specific and further object of the present invention is to increase the power output of Nd:YLF solid state lasers.
  • Yet a further object of the present invention is to produce a circularly symmetrical output without the use of a cylindrical lens.
  • a high power solid state laser comprises a laser resonator and a plurality of solid state laser rods mounted in pumping chambers.
  • the rods axe arranged in series and are constructed of a material having low thermal focusing and low thermal birefringence loss.
  • Means are arranged within the resonator for establishing a large intra-cavity beam diameter and active volume, and, thereby, a high TEM 00 laser output.
  • the laser rods are made of solid state Nd:YLF and the laser polarization is aligned along a crystal A axis to produce an output at 1053nm.
  • a first Nd:YLF rod is mounted in a pumping chamber within the resonator.
  • a second Nd:YLF rod is mounted in a second pumping chamber collinearly with the first rod.
  • the laser energy output of one rod is focused relative to the other rod by lens and cavity mirror means so as to establish a large intra-cavity beam diameter and active volume and/ thereby, a high TEM 00 laser output.
  • the rods are rotated 90o from one another about the laser axis.
  • a half-wave plate is aligned collinearly along the laser axis positioned between the pair of rdds and oriented to rotate the laser polarization by 90o thereby maintaining the appropriate laser wavelength output.
  • Figure 1 is a representational view of the primary parts of the laser of the present invention
  • Figure 2 is a block representation of the laser of Figure 1 operating in a Q-switched mode
  • Figure 3 is a representational view of a Nd:YLF laser rod showing the astigmatism in the X and Y directions of the thermal focusing;
  • Figure 4 is a representational view of two collinear Nd:YLF laser rods and a half-wave plate to produce circularly symmetrical output.
  • Figure 1 there is shown a plurality of Nd:YLF laser rods placed in series inside a resonator in order to effectively increase the overall rod length so as to achieve a large active volume and, thereby, a higher TEM 00 laser output.
  • the rods may be identically sized and shaped and, for achieving TEM 00 output, the rods are placed within a standard resonator such as of the Quantronix 4000 series.
  • the rods are 4X79 mm and are mounted in pumping chambers (not shown) in series within the resonator.
  • the rods are mounted collinearly with convex lens 13 therebetween.
  • the resonator includes high reflectance mirror 14 at one end and output mirror 15 at the other end.
  • Element 16 represents an intracavity Brewster plate polarizer in order to maintain the polarization and therefore the wavelength of laser operation.
  • the radii of curvature of convex reflective surfaces 14, 15 are 120 cm. These mirrors, together with lens 13, establish a large intra-cavity beam diameter.
  • An actual Nd:YLF laser in accordance with the construction of Fi ⁇ ure 1 has achieved a TEH 00 laser output of 40 watts, larger than any reported value to date.
  • Fig. 3 shows a single Nd:YLF laser rod with the direction of output shown by the arrow in the Z direction.
  • the difference in magnitude and sign of the thermal focusing in the X and Y directions has conventionally been corrected by employing an intracavity cylindrical lens in addition to the spherical lens used to expand the beam for large mode volume.
  • the output beam produced by the use of a cylindrical lens is circularly symmetrical in the X-Y plane.
  • Another prior way of achieving this correction with the arrangement of Fig. 1 is to make lens 13 a compound cylindrical-spherical lens with the cylindrial axis aligned to compensate for the astigmatism.
  • FIG. 1 illustrates, in block form, an arrangement wherein the invention described in Figure 1 may be operated in Q-switched or a mode-locked mode; Q-switch 21 is operated by driver 20 to create Q-switching action. Similarly, mode locked output can be produced using an intracavity mode- lock modulator.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Optics & Photonics (AREA)
  • Lasers (AREA)

Abstract

On obtient ce laser en plaçant une pluralité de bâtons à semiconducteurs Nd:YLF (11, 12) en série à l'intérieur d'une cavité laser. Chaque bâton (11, 12) est agencé dans une chambre de pompage pour produire une action laser. Une lentille sphérique (13) peut être incorporée dans la cavité pour créer avec les miroirs de la cavité (14, 15) un diamètre de faisceau important à l'intérieur de la cavité. Une lentille cylindrique distincte ou combinée avec la lentille sphérique (13) est prévue à l'intérieur de la cavité por compenser l'astigmatisme dans la focalisation thermique des bâtons de Nd:YLF. Dans un autre mode de réalisation, les bâtons fonctionnent par paires, une lame demi-onde étant agencée entre chaque paire de bâtons pour compenser l'astigmatisme. On obtient ainsi un laser capable d'une puissance de sortie importante en mode TEM00.
PCT/US1990/002210 1989-04-24 1990-04-24 LASERS A SEMICONDUCTEURS Nd:YLF MULTIKILOWATT Ceased WO1990013157A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US34241089A 1989-04-24 1989-04-24
US342,410 1989-04-24
US42158589A 1989-10-16 1989-10-16
US421,585 1989-10-16

Publications (1)

Publication Number Publication Date
WO1990013157A1 true WO1990013157A1 (fr) 1990-11-01

Family

ID=26992992

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1990/002210 Ceased WO1990013157A1 (fr) 1989-04-24 1990-04-24 LASERS A SEMICONDUCTEURS Nd:YLF MULTIKILOWATT

Country Status (1)

Country Link
WO (1) WO1990013157A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2665307A1 (fr) * 1990-07-11 1992-01-31 Amoco Corp Systeme laser adapte.
WO1999054970A3 (fr) * 1998-04-22 1999-12-02 Baasel Carl Lasertech Ensemble resonateur pour lasers a solide
CN117277038A (zh) * 2023-11-21 2023-12-22 武汉光谷航天三江激光产业技术研究院有限公司 基于双晶体串接的单端泵浦机载脉冲激光器及控制方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3242440A (en) * 1962-10-03 1966-03-22 American Optical Corp Time-controlled-output laser structure
US3258717A (en) * 1966-06-28 Laser cavity having spherical reflectors
US3629723A (en) * 1969-04-21 1971-12-21 American Optical Corp Athermal laser using a one-eighth wave faraday rotator
US4352186A (en) * 1980-03-13 1982-09-28 Sanders Associates, Inc. Laser crystal

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3258717A (en) * 1966-06-28 Laser cavity having spherical reflectors
US3242440A (en) * 1962-10-03 1966-03-22 American Optical Corp Time-controlled-output laser structure
US3629723A (en) * 1969-04-21 1971-12-21 American Optical Corp Athermal laser using a one-eighth wave faraday rotator
US4352186A (en) * 1980-03-13 1982-09-28 Sanders Associates, Inc. Laser crystal

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2665307A1 (fr) * 1990-07-11 1992-01-31 Amoco Corp Systeme laser adapte.
WO1999054970A3 (fr) * 1998-04-22 1999-12-02 Baasel Carl Lasertech Ensemble resonateur pour lasers a solide
US6788723B1 (en) 1998-04-22 2004-09-07 Carl Bassel Lasertechnik Gmbh Resonator array for solid-state lasers
CN117277038A (zh) * 2023-11-21 2023-12-22 武汉光谷航天三江激光产业技术研究院有限公司 基于双晶体串接的单端泵浦机载脉冲激光器及控制方法

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