CN111313223A - 2 mu m wave band inner cavity cascade Raman laser - Google Patents

2 mu m wave band inner cavity cascade Raman laser Download PDF

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CN111313223A
CN111313223A CN201911112425.0A CN201911112425A CN111313223A CN 111313223 A CN111313223 A CN 111313223A CN 201911112425 A CN201911112425 A CN 201911112425A CN 111313223 A CN111313223 A CN 111313223A
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raman
crystal
mirror
film
plated
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刘简
孔德龙
路想想
王杰英
裴栋梁
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707th Research Institute of CSIC
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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
    • H01S3/30—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects
    • H01S3/302—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects in an optical fibre
    • 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
    • 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
    • H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
    • H01S3/16—Solid materials
    • H01S3/163—Solid materials characterised by a crystal matrix
    • H01S3/1671—Solid materials characterised by a crystal matrix vanadate, niobate, tantalate
    • H01S3/1673—YVO4 [YVO]
    • 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
    • H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
    • H01S3/16—Solid materials
    • H01S3/1691—Solid materials characterised by additives / sensitisers / promoters as further dopants
    • H01S3/1696—Solid materials characterised by additives / sensitisers / promoters as further dopants transition metal

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  • Electromagnetism (AREA)
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  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Nonlinear Science (AREA)
  • Lasers (AREA)

Abstract

The invention relates to a 2 mu m wave band inner cavity cascade Raman laser, which belongs to the technical field of lasers and is characterized in that the Raman laser is sequentially provided with the following components in the light path direction: laser diode, pump coupling system, 1.5 μm Raman light reflector, Nd-doped3+Self-raman crystals, acousto-optic Q-switched devices, 1.9 μm raman mirror, CVD diamond crystals and 1.9 μm raman light output mirror. The invention is based on the stimulated Raman scattering effect and is formed by doping Nd3+The 1.3 μm fundamental frequency light generated from the raman crystal undergoes two raman shifts through itself and the CVD diamond crystal to generate 1.9 μm cascaded raman light. The invention has simple and compact structure, can meet various requirements in the fields of atmospheric science, medical treatment, laser remote sensing and the like by obtaining the laser output with the waveband of 2 mu m by adopting the technical scheme, and can also be used as a Ho laser and a mid-infrared OPOThe pump source of (1).

Description

2 mu m wave band inner cavity cascade Raman laser
Technical Field
The invention belongs to the technical field of lasers, and particularly relates to a 2-micrometer-waveband inner cavity cascade Raman laser.
Background
As is known to all, laser with the output wavelength of about 2 μm is in the human eye safety waveband and the weak absorption band of the atmosphere, and water molecules have strong absorption peaks in the waveband, so that the 2 μm waveband (1904-. In addition, 2 μm band laser can provide pump source for 3-5 μm and 8-12 μm mid-infrared band Optical Parametric Oscillator (OPO), which is an important research direction in the laser technology field.
The current methods for generating 2 μm band laser output are mainly: (1) using doped Tm3+Or Ho3+The laser gain medium of (1) is directly produced. And Ho doping3+Crystal phase ratio, Tm doping3+The crystal gain is smaller, so the Tm laser is more suitable for the continuous wave operation mode, and the Ho laser is more widely applied to the pulse or Q-switched operation mode. However, Ho3+At a pumping wavelength of 1.9 μm, the pumping process needs to be assisted by Tm3+Or Yb3+Energy conversion is performed. (2) The 2 μm band idler light output is generated by a 1 μm band laser pumped OPO. In the OPO process, the signal light and the idler light are generated simultaneously, so that the conversion efficiency of a single wavelength is relatively limited.
Disclosure of Invention
The invention provides a 2 mu m waveband cavity cascade Raman laser for solving the technical problems in the prior art, wherein the 2 mu m waveband cavity cascade Raman laser is doped with Nd based on SRS effect3+The 1.5 μm raman light generated from the raman crystal is again raman shifted by the CVD diamond crystal to obtain a 1.9 μm cascade raman light output.
The invention aims to provide a 2 mu m wave band inner cavity cascade Raman laser, which is sequentially provided with the following components in the light path direction: a laser diode (1), a pump coupling system (2), a 1.5 mu m Raman light reflector (3), and an Nd-doped Raman light reflector3+The device comprises a self-Raman crystal (4), an acousto-optic Q-switching device (5), a 1.9 mu m Raman light reflecting mirror (6), a CVD diamond crystal (7) and a 1.9 mu m Raman light output mirror (8); wherein:
the laser diode (1) emits Nd-doped light3+Pump light in a band is absorbed by the self-Raman crystal (4) and is focused on the Nd-doped material through the pump coupling system (2)3+Self-raman crystal (4);
to the Nd-doped3+Polishing two end faces of the Raman crystal (4), and plating a pumping light antireflection film emitted by the laser diode (1), a 1.3 mu m waveband fundamental frequency light antireflection film and a 1.5 mu m waveband Raman light antireflection film;
plating a 1.3 mu m wave band fundamental frequency light antireflection film and a 1.5 mu m wave band Raman light antireflection film on two end faces of the acousto-optic Q-switching device (5);
two surfaces of the 1.5 mu m Raman light reflecting mirror (3) are plated with a pumping light antireflection film emitted by the laser diode, a 1.06 mu m waveband antireflection film and a 1.6 mu m waveband antireflection film, and the 1.5 mu m Raman light reflecting mirror (3) is close to the Nd-doped part3+Plating a 1.3 mu m wave band high-reflection film and a 1.5 mu m wave band high-reflection film on the end face of the Raman crystal (4);
the 1.9 mu m Raman light reflecting mirror (6) is a flat mirror, two surfaces of the 1.9 mu m Raman light reflecting mirror (6) are plated with a 1.3 mu m waveband high-transmittance film and a 1.5 mu m waveband high-transmittance film, and the end surface of the 1.9 mu m Raman light reflecting mirror (6) close to the CVD diamond crystal (7) is plated with a 1.9 mu m waveband high-reflectance film;
polishing two end faces of the CVD diamond crystal (7), and plating a 1.3 mu m wave band fundamental frequency light antireflection film, a 1.5 mu m wave band Raman light antireflection film and a 1.9 mu m wave band Raman light antireflection film;
two end faces of the 1.9-micron Raman light output mirror (8) are plated with near-1.06-micron antireflection films and 1.6-micron waveband antireflection films, and the end face, close to the CVD diamond crystal (7), of the 1.9-micron Raman light output mirror (8) is plated with a 1.3-micron waveband high-reflection film and a 1.5-micron waveband high-reflection film.
Further: a first total reflection mirror is arranged between the acousto-optic Q-switching device (5) and the 1.9 mu m Raman light reflection mirror (6); a second total reflection mirror is arranged between the CVD diamond crystal (7) and the 1.9 mu m Raman light output mirror (8); the first total reflection mirror and the second total reflection mirror form a folding cavity total reflection mirror.
Further: the above Nd-doped3+The self-Raman crystal (4) is Nd: YVO4The crystal is the 1.The wavelength of the fundamental frequency light of the 3 mu m wave band is 1342 nm.
Further: the wavelength of the laser diode (1) is 880nm, and the Nd is doped3+YVO (YVO) as a-cut Nd from Raman crystal (4)4Crystal of said Nd-doped3+The crystal size of the self-Raman crystal (4) was 3mm × 3mm × 10mm, the doping concentration was 0.5 at.%, and Nd was doped3+Coating 880nm, 1342nm and 1525nm antireflection films on two end faces of the Raman crystal (4), and wrapping Nd-doped indium sheet3+The self-Raman crystal (4) is arranged in the heat sink; the acousto-optic Q-switching device (5) adopts an acousto-optic Q-switching crystal with the length of 20mm, and two end faces of the acousto-optic Q-switching device (5) are plated with 1342nm antireflection films and 1525nm antireflection films; the CVD diamond crystal (7) has a size of 2mm x 8mm<110>Cutting along the direction, and plating 1342nm antireflection film, 1525nm antireflection film and 1914nm antireflection film on the two end faces of the CVD diamond crystal (7).
Further: the 1.5 mu m Raman light reflector (3) is a concave mirror with the curvature radius of 150mm, 880nm antireflection film, 1064nm antireflection film and 1634nm antireflection film are plated on the two sides of the 1.5 mu m Raman light reflector (3), YVO is used as a part of the 1.5 mu m Raman light reflector (3) close to Nd4The end face of the crystal (4) is plated with a 1342nm high-reflection film and a 1525nm high-reflection film; the 1.9 mu m Raman light output mirror (8) is a flat mirror, the two surfaces of the 1.9 mu m Raman light output mirror (8) are plated with a 1064nm antireflection film and a 1634nm antireflection film, the end surface of the 1.9 mu m Raman light output mirror (8) close to the CVD diamond crystal (7) is plated with a 1342nm high-reflection film and a 1525nm high-reflection film, and the transmittance to 1914nm is T-5%; the 1.9 mu m Raman light reflecting mirror (6) is a flat mirror, the 1342nm high-transmittance film and the 1525nm high-transmittance film are plated on the two sides of the 1.9 mu m Raman light reflecting mirror (6), and the 1914nm high-reflectance film is plated on the side, close to the CVD diamond crystal 7, of the 1.9 mu m Raman light reflecting mirror (6).
Further: the above Nd-doped3+The self-Raman crystal (4) is Nd: GdVO4The wavelength of the fundamental frequency light of the 1.3 mu m wave band is 1341 nm.
Further: the wavelength of the laser diode (1) is 808 nm; nd doped3+The self-Raman crystal (4) is a-cut Nd: GdVO4Crystal doped with Nd3+The crystal size of the self-Raman crystal (4) was 3mm × 3mm × 10mm, the doping concentration was 0.3 at.%, and Nd was doped3+808nm antireflection film, 1341nm antireflection film and 1521nm antireflection film are plated on two end faces of the Raman crystal (4)Film, doping with Nd3+The self-Raman crystal (4) is wrapped by an indium sheet and is arranged in the heat sink; the acousto-optic Q-switching device (5) adopts an acousto-optic Q-switching crystal with the length of 20mm, and two end faces of the acousto-optic Q-switching device (5) are plated with 1341nm antireflection films and 1521nm antireflection films; the size of the CVD diamond crystal (7) is 2mm multiplied by 8mm, the CVD diamond crystal (7) is along<110>Cutting along the direction, and plating 1341nm antireflection film, 1521nm antireflection film and 1907nm antireflection film on the two end faces of the CVD diamond crystal (7).
Further: the 1.5 mu m Raman light reflector (3) is a flat mirror, the double surfaces of the 1.5 mu m Raman light reflector (3) are plated with an anti-reflection film of 808nm, an anti-reflection film of 1063nm and an anti-reflection film of 1633nm, the 1.5 mu m Raman light reflector (3) is close to Nd, GdVO4The end face of the crystal (4) is plated with a 1341nm high-reflection film and a 1521nm high-reflection film; the 1.9-micron Raman light output mirror (8) is a flat mirror, the 1063nm and 1633nm antireflection films are plated on the two surfaces of the 1.9-micron Raman light output mirror (8), a 1341nm high-reflection film and a 1521nm high-reflection film are plated on one surface, close to the CVD diamond crystal (7), of the 1.9-micron Raman light output mirror (8), and the transmittance to 1907nm is T-5%; the 1.9 mu m Raman light reflecting mirror (6) is a flat mirror, the 1341nm high-transmittance film and the 1521nm high-transmittance film are plated on the two sides of the 1.9 mu m Raman light reflecting mirror (6), and the 1907nm high-reflectance film is plated on the end face, close to the CVD diamond crystal (7), of the 1.9 mu m Raman light reflecting mirror (6); the first total reflection mirror and the second total reflection mirror are concave mirrors with the curvature radius of 100mm, and a 1341nm high reflection film, a 1521nm high reflection film and a 1907nm high reflection film are plated on the concave surfaces of the concave mirrors.
Further: the above Nd-doped3+The self-Raman crystal (4) is Nd: LuVO4Or Nd is KGW.
The invention has the advantages and positive effects that:
by adopting the technical scheme: the invention is prepared by doping Nd3+The 1.3 mu m waveband base frequency light generated by the self-Raman crystal is subjected to Raman frequency shift twice through the self-Raman crystal and the CVD diamond crystal, so that 1.9 mu m waveband cascade Raman light is generated, various requirements in the fields of atmospheric science, medical treatment, laser remote sensing and the like can be met, and the self-Raman crystal can be used as a pump source of a Ho laser and a mid-infrared OPO. By adopting the mode of pumping CVD diamond crystals in the inner cavity and combining the optimized design of the resonant cavity, the high-power and high-efficiency Raman light output with the diameter of 1.9 mu m can be obtained, and the structure is simple and compact.
Drawings
FIG. 1 is a light path diagram of a first preferred embodiment of the present invention;
FIG. 2 is a light path diagram of a second preferred embodiment of the present invention;
wherein: 1. a laser diode; 2. a pump coupling system; 3. 1.5 μm Raman mirror; 4. nd doped3+A self-raman crystal; 5. an acousto-optic Q-switch device; 6. 1.9 μm raman mirror; 7. CVD diamond crystals; 8. 1.9 μm raman light output mirror.
Detailed Description
In order to further understand the contents, features and effects of the present invention, the following embodiments are illustrated and described in detail with reference to the accompanying drawings:
stimulated Raman Scattering (SRS) is an efficient third-order nonlinear frequency conversion technique. Compared with common Raman crystals such as tungstate, vanadate and nitrate, the diamond crystal prepared based on the Chemical Vapor Deposition (CVD) method has larger Raman frequency shift (1332.3 cm)-1) A high Raman gain coefficient, a large thermal conductivity coefficient and a small thermal expansion coefficient, so that the diamond Raman Laser has a small influence of thermal effect under high pumping power and is easy to realize high-power and high-efficiency Raman light output, as disclosed in the documents [ Efficient Raman frequency conversion of high-power fiber lasers in diode, Laser photonic rev.9(4), 405-materials 411, 2015-materials 2015 ]]The output power of the raman laser based on CVD diamond crystals reported in (a) is over 300W, and the conversion efficiency is as high as 61%.
A 2 μm band intracavity cascaded raman laser comprising:
laser diode 1, pumping coupling system 2, Nd-doped3+A self-Raman crystal 4, an acousto-optic Q-switching device 5, a CVD diamond crystal 7, a 1.5 mu m Raman light reflecting mirror 3, a 1.9 mu m Raman light reflecting mirror 6 and a 1.9 mu m Raman light output mirror 8,
emitting the Nd-doped laser diode3+Pump light in a self-Raman crystal absorption band is focused on the Nd-doped crystal through the pump coupling system3+self-Raman on the crystal; the Nd doped3+Form population inversion from Raman crystal, and increase the fundamental frequency of 1.3 μm with the increase of pump lightGenerating 1.3 μm fundamental frequency light under the feedback action of the optical resonant cavity;
when the intensity of 1.3 mu m fundamental frequency light exceeds the Nd-doped intensity3+After the Raman threshold of the self-Raman crystal, generating 1.5 mu m first-order Stokes Raman light under the action of SRS nonlinear frequency conversion, and oscillating in a 1.5 mu m Raman light resonant cavity;
the 1.5-micron Raman optical resonant cavity and the 1.3-micron fundamental frequency optical resonant cavity are shared resonant cavities and are composed of the 1.5-micron Raman optical reflector and the 1.9-micron Raman optical output mirror;
the CVD diamond crystal is placed in the 1.5-micron Raman optical resonant cavity, and an inner cavity pumping mode is adopted, so that higher power density in the cavity can be fully utilized, larger 1.5-micron pumping optical power is provided for the CVD diamond crystal, and high-power and high-efficiency Raman optical output is easily obtained;
when the intensity of 1.5 μm Raman light exceeds the Raman threshold of the CVD diamond crystal, 1332.3cm-1Generating 1.9 μm first-order Stokes Raman light under Raman frequency shift, forming stable oscillation in a 1.9 μm Raman optical resonator formed by the 1.9 μm Raman optical reflector and the 1.9 μm Raman optical output mirror, and outputting via the 1.9 μm Raman optical output mirror part;
the 1.9-micron Raman optical reflector is placed between the acousto-optic Q-switch device and the CVD diamond crystal, so that on one hand, the intracavity loss of 1.9-micron Raman light can be reduced, and on the other hand, the mode matching between the 1.9-micron Raman light and 1.5-micron pump light thereof is easy to realize, and the high-efficiency conversion of the 1.9-micron Raman light is realized;
the Nd doped3+Polishing two end faces of the Raman crystal, and plating an antireflection film for transmitting pump light, 1.3 mu m base frequency light and 1.5 mu m Raman light wavelength by the laser diode;
two end faces of the CVD diamond crystal are polished, and a 1.3 mu m fundamental frequency light, a 1.5 mu m Raman light and a 1.9 mu m Raman light wavelength antireflection film are plated.
Two end faces of the acousto-optic Q-switching device are plated with 1.3 mu m fundamental frequency light and 1.5 mu m Raman light wavelength antireflection films, the acousto-optic Q-switching device is used for realizing pulse operation of a laser, and the nonlinear conversion efficiency of a Raman process is improved by improving peak power.
The 1.5-micron Raman light reflecting mirror can be a concave mirror or a flat mirror, and both surfaces of the 1.5-micron Raman light reflecting mirror are plated with pumping light emitted by the laser diode, 1.06-micron and 1.6-micron wavelength antireflection films so as to inhibit parasitic wavelength oscillation; near the Nd-doped layer3+Plating a 1.3 mu m and 1.5 mu m wavelength high-reflection film on one surface of the Raman crystal;
the 1.9 mu m Raman light reflector is a flat mirror, two surfaces of the flat mirror are plated with 1.3 mu m and 1.5 mu m wavelength high-transmittance films, and one surface close to the CVD diamond crystal is plated with a 1.9 mu m wavelength high-reflectance film;
the 1.9 μm Raman light output mirror can be a concave mirror or a flat mirror, two surfaces of the mirror are plated with 1.06 μm and 1.6 μm wavelength antireflection films, one surface close to the CVD diamond crystal is plated with 1.3 μm and 1.5 μm wavelength high reflection films, and the mirror has certain transmittance for 1.9 μm wavelength.
Referring to fig. 1, a 2 μm band intracavity cascade raman laser includes: laser diode 1, pump coupling system 2, 1.5 μm Raman light reflector 3, Nd-doped3+A self-Raman crystal 4, an acousto-optic Q-switching device 5, a 1.9 μm Raman light reflecting mirror 6, a CVD diamond crystal 7, a 1.9 μm Raman light output mirror 8,
wherein, doped with Nd3+YVO is selected from Nd as self-Raman crystal 44The fundamental wavelength of the crystal is 1064nm and 1342nm, mode competition exists between the crystal and the crystal, and oscillation of the 1064nm fundamental frequency light needs to be inhibited in the invention; nd: YVO4The Raman frequency shift of the crystal is 890cm-1The wavelength of first-order Stokes Raman light corresponding to the 1342nm fundamental frequency light is 1525 nm; the 1525nm Raman optical resonant cavity and the 1342nm fundamental frequency optical resonant cavity share a resonant cavity, and the resonant cavity consists of a 1.5-micrometer Raman optical reflector 3 and a 1.9-micrometer Raman optical output mirror 8; the CVD diamond crystal 7 is placed in a resonant cavity of 1342nm fundamental frequency light and 1525nm Raman light in an inner cavity pumping mode, when the intensity of the 1342nm fundamental frequency light in the cavity exceeds the Raman threshold of the CVD diamond crystal, 1634nm first-order Stokes Raman light can be generated, and the conversion process of the 1342nm fundamental frequency light to the 1525nm Raman light is influenced, so that the oscillation of the 1634nm Raman light is required to be inhibited in the invention; the first-order Stokes Raman light wavelength of the CVD diamond crystal corresponding to the 1525nm Raman light is 1914nm, and a 1914nm Raman light resonant cavity consists of a 1.9 mu m Raman light reflection mirror 6 and a 1.9 mu m Raman lightAn output mirror 8.
The 880nm laser diode 1 emits Nd: YVO4The crystal corresponding to the pump light is focused on the Nd-doped Nd by a pump coupling system 2 formed by an energy transmission fiber and a coupling lens group3+From the raman crystal 4; nd doped3+YVO (YVO) with self-Raman crystal 4 as a-cut Nd4The crystal, the crystal size is 3mm x 10mm, the doping concentration is 0.5 at.%, 880nm, 1342nm and 1525nm wavelength antireflection films are plated on two end faces, an indium sheet is wrapped and placed in a heat sink, and the working temperature is controlled by adopting a cooling circulating water system; the acousto-optic Q-switching device 5 adopts an acousto-optic Q-switching crystal with the length of 20mm, and antireflection films with the wavelengths of 1342nm and 1525nm are plated on two end faces; the CVD diamond crystal 7 has a size of 2mm x 8mm, along<110>Cutting along the direction, and plating antireflection films with the wavelengths of 1342nm, 1525nm and 1914nm on two end faces.
The 1.5 μm Raman reflector 3 is a concave mirror with curvature radius of 150mm, and is coated with 880nm, 1064nm and 1634nm antireflection films on both sides, near Nd, YVO4One side of the crystal 4 is plated with 1342nm and 1525nm high-reflection films; the 1.9 μm Raman light output mirror 8 is a flat mirror, is coated with anti-reflection films of 1064nm and 1634nm on both sides, is coated with high-reflection films of 1342nm and 1525nm on the side close to the CVD diamond crystal 7, and has a transmittance T of 5% to 1914 nm; the 1.9 μm Raman light reflector 6 is a flat mirror, and is plated with 1342nm and 1525nm high-transmittance films on both sides, and a 1914nm high-reflectance film on the side close to the CVD diamond crystal 7.
Nd:YVO4The crystal 4 absorbs 880nm pump light to form particle number reversal, and generates 1342nm fundamental frequency light under the feedback action of a 1342nm fundamental frequency light resonant cavity formed by the 1.5-micron Raman light reflecting mirror 3 and the 1.9-micron Raman light output mirror 8; the 1342nm fundamental frequency light realizes pulse operation under the action of the acousto-optic Q-switching device 5 to obtain higher peak power when passing through Nd: YVO4When the self-Raman crystal 4 easily exceeds a Raman threshold, the SRS effect is generated, and 1525nm Raman light is generated; the 1.5-micron Raman light reflecting mirror 3 and the 1.9-micron Raman light output mirror 8 simultaneously form a 1525nm Raman light resonant cavity, and the concave-flat cavity structure is adopted, so that 1525nm Raman light obtains smaller spot size at the CVD diamond crystal 7, and the power density of 1525nm pump light in the CVD diamond crystal 7 is improved; 1525nm pump light along CVD diamond crystals 7<110>Direction of incidence, polarization direction and<111>the directions are consistent, canTo obtain the maximum Raman gain coefficient at 1332.3cm-11914nm Raman light is generated under the Raman frequency shift, stably oscillates in a 1914nm Raman light resonant cavity formed by the 1.9 μm Raman light reflecting mirror 6 and the 1.9 μm Raman light output mirror 8, and is output through the 1.9 μm Raman light output mirror 8; the 1.9 μm Raman mirror 6 functions to prevent 1914nm Raman light from passing through Nd: YVO4Loss is caused when the crystal 4 and the acousto-optic Q-switching device 5 are used, and on the other hand, mode matching between 1914nm Raman light and 1525nm pump light thereof can be realized by adjusting the distance between the 1.9-micron Raman light reflecting mirror 6 and the 1.9-micron Raman light output mirror 8, so that efficient conversion of the 1914nm Raman light is realized.
Please refer to fig. 2, example 2
A 2 μm band intracavity cascaded raman laser comprising: laser diode 1, pump coupling system 2, 1.5 μm Raman light reflector 3, Nd-doped3+The self-Raman crystal 4, the acousto-optic Q-switching device 5, the 1.9 mu m Raman light reflecting mirror 6, the CVD diamond crystal 7, the 1.9 mu m Raman light output mirror 8 and the folding cavity total reflection mirror 9. By adopting the structure of the folded cavity, a smaller spot size can be obtained at the CVD diamond crystal 7 to improve the conversion efficiency of SRS action in the CVD diamond crystal 7.
In this example, Nd was doped3+The self-Raman crystal 4 selects Nd: GdVO4The fundamental wavelength of the crystal is 1063nm and 1341nm, mode competition exists between the crystal and the crystal, and oscillation of the 1063nm fundamental frequency light needs to be inhibited in the invention; nd: GdVO4The Raman frequency shift of the crystal is 882cm-1The wavelength of first-order Stokes Raman light corresponding to the base frequency light of 1341nm is 1521 nm; when the intensity of 1341nm fundamental frequency light in the cavity exceeds the Raman threshold of the CVD diamond crystal, 1633nm first-order Stokes Raman light can be generated, and the conversion process of the 1341nm fundamental frequency light to 1521nm Raman light is influenced, so that the oscillation of the 1633nm Raman light is required to be inhibited in the invention; the first-order stokes raman wavelength of the CVD diamond crystal corresponding to the 1521nm raman light is 1907 nm.
The 808nm laser diode 1 emits Nd: GdVO4The crystal corresponding to the pump light is focused on the Nd-doped Nd by a pump coupling system 2 formed by an energy transmission fiber and a coupling lens group3+self-RamanOn the crystal 4; nd doped3+GdVO (natural gas) with self-Raman crystal 4 as a-cut Nd4The crystal, the crystal size is 3mm x 10mm, the doping concentration is 0.3 at.%, the two end faces are plated with anti-reflection films with the wavelengths of 808nm, 1341nm and 1521nm, the crystal is wrapped by indium sheets and placed in a heat sink, and the working temperature of the crystal is controlled by adopting a cooling circulating water system; the acousto-optic Q-switching device 5 adopts an acousto-optic Q-switching crystal with the length of 20mm, and antireflection films with the wavelengths of 1341nm and 1521nm are plated on two end faces; the CVD diamond crystal 7 has a size of 2mm x 8mm, along<110>Cutting along the direction, and plating antireflection films with the wavelengths of 1341nm, 1521nm and 1907nm on two end faces.
The 1.5 μm Raman light reflector 3 is a flat mirror, and is coated with antireflection films of 808nm, 1063nm and 1633nm on both sides, and GdVO is near Nd4One side of the crystal 4 is plated with 1341nm and 1521nm high-reflection films; the 1.9 μm Raman light output mirror 8 is a flat mirror, is coated with anti-reflection films of 1063nm and 1633nm on two sides, is coated with high-reflection films of 1341nm and 1521nm on one side close to the CVD diamond crystal 7, and has a transmittance T of 5% for 1907 nm; the 1.9 μm Raman light reflector 6 is a flat mirror, and is plated with 1341nm and 1521nm high-transmittance films on two sides, and a 1907nm high-reflectance film on one side close to the CVD diamond crystal 7; the folding cavity total reflection mirror is a concave mirror with the curvature radius of 100mm, 1341nm, 1521nm and 1907nm high reflection films are plated on the concave surface, 1521nm Raman light can form a smaller light spot size in the folding cavity total reflection mirror (composed of a first total reflection mirror 9-1 and a second total reflection mirror 9-2) by adjusting the distance between the cavity mirrors, and the CVD diamond crystal 7 is placed at the position.
Nd:GdVO4The crystal 4 absorbs 808nm pump light to form particle number reversal, and generates 1341nm fundamental frequency light under the feedback action of a 1341nm fundamental frequency light resonant cavity consisting of a 1.5-micron Raman light reflecting mirror 3, a folding cavity total reflection mirror and a 1.9-micron Raman light output mirror 8; the 1341nm fundamental frequency light realizes pulse operation under the action of the acousto-optic Q-switching device 5 to obtain higher peak power, and GdVO is added when the intensity of the 1341nm fundamental frequency light exceeds Nd4Generating 1521nm Raman light after the Raman threshold of the Raman crystal 4, and oscillating in a 1521nm Raman light resonant cavity formed by the 1.5 μm Raman light reflecting mirror 3, the folding cavity total reflection mirror and the 1.9 μm Raman light output mirror 8 at the same time; 1521nm pump light along CVD diamond crystals 7<110>The direction of the light is transmitted,<111>polarization direction at 1332.3cm-11907nm Raman light at 1.9 μm Raman frequency shiftThe Raman light reflector 6, the folding cavity total reflection mirror and the 1.9 mu m Raman light output mirror 8 form a 1907nm Raman light resonant cavity which stably oscillates and is output through the 1.9 mu m Raman light output mirror 8.
In the two embodiments, the 808nm traditional pumping mode and the 880nm resonance pumping mode are respectively adopted, and in the concrete implementation, the Nd-doped mode can be further reduced by adopting the 914nm resonance pumping mode3+Embodiments of the present invention are not limited in this respect from the thermal load on the raman crystal.
In the above examples, Nd is doped3+The self-Raman crystal can also be Nd: LuVO4The raman shift of crystals such as Nd: KGW can be found in related documents, and the corresponding 1.3 μm fundamental light, 1.5 μm raman light and 1.9 μm output wavelength are changed, which is not limited in the embodiment of the present invention when the invention is specifically implemented.
In the embodiment of the invention, Nd can be selectively doped according to actual needs3+The doping concentration or size of the raman crystal and CVD diamond crystal, and the radius of curvature and transmittance of each cavity mirror, are not limited in this embodiment of the invention when implemented specifically.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications, equivalent changes and modifications made to the above embodiment according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.

Claims (9)

1. A2 μm wave band inner cavity cascade Raman laser is characterized in that: a laser diode (1), a pump coupling system (2), a 1.5 mu m Raman light reflector (3), and an Nd-doped Raman light reflector3+The device comprises a self-Raman crystal (4), an acousto-optic Q-switching device (5), a 1.9 mu m Raman light reflecting mirror (6), a CVD diamond crystal (7) and a 1.9 mu m Raman light output mirror (8); wherein:
the laser diode (1) emits Nd-doped light3+Pump light in a band is absorbed by the self-Raman crystal (4) and is focused on the Nd-doped material through the pump coupling system (2)3+Self-raman crystal (4);
to the Nd-doped3+Polishing two end faces of the Raman crystal (4), and plating a pumping light antireflection film emitted by the laser diode (1), a 1.3 mu m waveband fundamental frequency light antireflection film and a 1.5 mu m waveband Raman light antireflection film;
plating a 1.3 mu m wave band fundamental frequency light antireflection film and a 1.5 mu m wave band Raman light antireflection film on two end faces of the acousto-optic Q-switching device (5);
two surfaces of the 1.5 mu m Raman light reflecting mirror (3) are plated with a pumping light antireflection film emitted by the laser diode, a 1.06 mu m waveband antireflection film and a 1.6 mu m waveband antireflection film, and the 1.5 mu m Raman light reflecting mirror (3) is close to the Nd-doped part3+Plating a 1.3 mu m wave band high-reflection film and a 1.5 mu m wave band high-reflection film on the end face of the Raman crystal (4);
the 1.9 mu m Raman light reflecting mirror (6) is a flat mirror, two surfaces of the 1.9 mu m Raman light reflecting mirror (6) are plated with a 1.3 mu m waveband high-transmittance film and a 1.5 mu m waveband high-transmittance film, and the end surface of the 1.9 mu m Raman light reflecting mirror (6) close to the CVD diamond crystal (7) is plated with a 1.9 mu m waveband high-reflectance film;
polishing two end faces of the CVD diamond crystal (7), and plating a 1.3 mu m wave band fundamental frequency light antireflection film, a 1.5 mu m wave band Raman light antireflection film and a 1.9 mu m wave band Raman light antireflection film;
two end faces of the 1.9-micron Raman light output mirror (8) are plated with 1.06-micron waveband antireflection films and 1.6-micron waveband antireflection films, and the end face, close to the CVD diamond crystal (7), of the 1.9-micron Raman light output mirror (8) is plated with 1.3-micron waveband high-reflection films and 1.5-micron waveband high-reflection films.
2. The 2 μm band intracavity cascaded raman laser of claim 1, wherein: a first total reflection mirror is arranged between the acousto-optic Q-switching device (5) and the 1.9 mu m Raman light reflection mirror (6); a second total reflection mirror is arranged between the CVD diamond crystal (7) and the 1.9 mu m Raman light output mirror (8); the first total reflection mirror and the second total reflection mirror form a folding cavity total reflection mirror.
3. The 2 μm band intracavity cascaded raman laser of claim 1 or 2, wherein: the above Nd-doped3+The self-Raman crystal (4) is Nd: YVO4Crystal of fundamental light wave of 1.3 μm bandThe length was 1342 nm.
4. The 2 μm band intracavity cascaded raman laser of claim 3, wherein: the wavelength of the laser diode (1) is 880nm, and the Nd is doped3+YVO (YVO) as a-cut Nd from Raman crystal (4)4Crystal of said Nd-doped3+The crystal size of the self-Raman crystal (4) was 3mm × 3mm × 10mm, the doping concentration was 0.5 at.%, and Nd was doped3+Coating 880nm, 1342nm and 1525nm antireflection films on two end faces of the Raman crystal (4), and wrapping Nd-doped indium sheet3+The self-Raman crystal (4) is arranged in the heat sink; the acousto-optic Q-switching device (5) adopts an acousto-optic Q-switching crystal with the length of 20mm, and two end faces of the acousto-optic Q-switching device (5) are plated with 1342nm antireflection films and 1525nm antireflection films; the CVD diamond crystal (7) has a size of 2mm x 8mm<110>Cutting along the direction, and plating 1342nm antireflection film, 1525nm antireflection film and 1914nm antireflection film on the two end faces of the CVD diamond crystal (7).
5. The 2 μm band intracavity cascaded raman laser of claim 3, wherein: the 1.5 mu m Raman light reflector (3) is a concave mirror with the curvature radius of 150mm, 880nm antireflection film, 1064nm antireflection film and 1634nm antireflection film are plated on the two sides of the 1.5 mu m Raman light reflector (3), YVO is used as a part of the 1.5 mu m Raman light reflector (3) close to Nd4The end face of the crystal (4) is plated with a 1342nm high-reflection film and a 1525nm high-reflection film; the 1.9 mu m Raman light output mirror (8) is a flat mirror, the two surfaces of the 1.9 mu m Raman light output mirror (8) are plated with a 1064nm antireflection film and a 1634nm antireflection film, the end surface of the 1.9 mu m Raman light output mirror (8) close to the CVD diamond crystal (7) is plated with a 1342nm high-reflection film and a 1525nm high-reflection film, and the transmittance to 1914nm is T-5%; the 1.9 mu m Raman light reflecting mirror (6) is a flat mirror, the 1342nm high-transmittance film and the 1525nm high-transmittance film are plated on the two sides of the 1.9 mu m Raman light reflecting mirror (6), and the 1914nm high-reflectance film is plated on the side, close to the CVD diamond crystal 7, of the 1.9 mu m Raman light reflecting mirror (6).
6. The 2 μm band intracavity cascaded raman laser of claim 1 or 2, wherein: the above Nd-doped3+The self-Raman crystal (4) is Nd: GdVO4The wavelength of the fundamental frequency light of the 1.3 mu m wave band is 1341 nm.
7. The 2 μm band intracavity cascaded raman laser of claim 6, wherein: the wavelength of the laser diode (1) is 808 nm; nd doped3+The self-Raman crystal (4) is a-cut Nd: GdVO4Crystal doped with Nd3+The crystal size of the self-Raman crystal (4) was 3mm × 3mm × 10mm, the doping concentration was 0.3 at.%, and Nd was doped3+808nm antireflection films, 1341nm antireflection films and 1521nm antireflection films are plated on two end faces of the Raman crystal (4) and are doped with Nd3+The self-Raman crystal (4) is wrapped by an indium sheet and is arranged in the heat sink; the acousto-optic Q-switching device (5) adopts an acousto-optic Q-switching crystal with the length of 20mm, and two end faces of the acousto-optic Q-switching device (5) are plated with 1341nm antireflection films and 1521nm antireflection films; the size of the CVD diamond crystal (7) is 2mm multiplied by 8mm, the CVD diamond crystal (7) is along<110>Cutting along the direction, and plating 1341nm antireflection film, 1521nm antireflection film and 1907nm antireflection film on the two end faces of the CVD diamond crystal (7).
8. The 2 μm band intracavity cascaded raman laser of claim 6, wherein: the 1.5 mu m Raman light reflector (3) is a flat mirror, the double surfaces of the 1.5 mu m Raman light reflector (3) are plated with an anti-reflection film of 808nm, an anti-reflection film of 1063nm and an anti-reflection film of 1633nm, the 1.5 mu m Raman light reflector (3) is close to Nd, GdVO4The end face of the crystal (4) is plated with a 1341nm high-reflection film and a 1521nm high-reflection film; the 1.9-micron Raman light output mirror (8) is a flat mirror, the 1063nm and 1633nm antireflection films are plated on the two surfaces of the 1.9-micron Raman light output mirror (8), a 1341nm high-reflection film and a 1521nm high-reflection film are plated on one surface, close to the CVD diamond crystal (7), of the 1.9-micron Raman light output mirror (8), and the transmittance to 1907nm is T-5%; the 1.9 mu m Raman light reflecting mirror (6) is a flat mirror, the 1341nm high-transmittance film and the 1521nm high-transmittance film are plated on the two sides of the 1.9 mu m Raman light reflecting mirror (6), and the 1907nm high-reflectance film is plated on the end face, close to the CVD diamond crystal (7), of the 1.9 mu m Raman light reflecting mirror (6); the first total reflection mirror and the second total reflection mirror are concave mirrors with the curvature radius of 100mm, and a 1341nm high reflection film, a 1521nm high reflection film and a 1907nm high reflection film are plated on the concave surfaces of the concave mirrors.
9. The 2 μm band intracavity cascaded raman laser of claim 1, wherein: the above Nd-doped3+The self-Raman crystal (4) is Nd: LuVO4Or Nd is KGW.
CN201911112425.0A 2019-11-14 2019-11-14 2 mu m wave band inner cavity cascade Raman laser Pending CN111313223A (en)

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Publication number Priority date Publication date Assignee Title
CA2076735A1 (en) * 1992-08-24 1994-02-25 Georges R. Fournier Stimulated raman laser or amplifier using axicon pumping
CN102104231A (en) * 2011-01-06 2011-06-22 中国科学院上海光学精密机械研究所 Graphite Raman locked mode laser
CN102770588A (en) * 2010-01-18 2012-11-07 六号元素有限公司 CVD single crystal diamond material
CN107069428A (en) * 2017-02-09 2017-08-18 厦门理工学院 Based on WS2Passive Q-adjusted c cutting Nd:YVO4From Raman eye-safe laser
CN109873292A (en) * 2019-03-12 2019-06-11 天津大学 The blue light solid state laser device of thulium gain media is mixed in a kind of raman laser inner cavity pumping
CN110233417A (en) * 2019-05-28 2019-09-13 中国科学院理化技术研究所 A kind of device improving diamond raman laser efficiency

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2076735A1 (en) * 1992-08-24 1994-02-25 Georges R. Fournier Stimulated raman laser or amplifier using axicon pumping
CN102770588A (en) * 2010-01-18 2012-11-07 六号元素有限公司 CVD single crystal diamond material
CN102104231A (en) * 2011-01-06 2011-06-22 中国科学院上海光学精密机械研究所 Graphite Raman locked mode laser
CN107069428A (en) * 2017-02-09 2017-08-18 厦门理工学院 Based on WS2Passive Q-adjusted c cutting Nd:YVO4From Raman eye-safe laser
CN109873292A (en) * 2019-03-12 2019-06-11 天津大学 The blue light solid state laser device of thulium gain media is mixed in a kind of raman laser inner cavity pumping
CN110233417A (en) * 2019-05-28 2019-09-13 中国科学院理化技术研究所 A kind of device improving diamond raman laser efficiency

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Application publication date: 20200619