WO2015074246A1 - 径向偏振薄片激光器 - Google Patents

径向偏振薄片激光器 Download PDF

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Publication number
WO2015074246A1
WO2015074246A1 PCT/CN2013/087687 CN2013087687W WO2015074246A1 WO 2015074246 A1 WO2015074246 A1 WO 2015074246A1 CN 2013087687 W CN2013087687 W CN 2013087687W WO 2015074246 A1 WO2015074246 A1 WO 2015074246A1
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Prior art keywords
laser
brewster
gain medium
film
radially polarized
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PCT/CN2013/087687
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English (en)
French (fr)
Inventor
肖磊
龚成万
赵建涛
杨锦彬
宁艳华
高云峰
Original Assignee
深圳市大族激光科技股份有限公司
深圳市大族数控科技有限公司
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Application filed by 深圳市大族激光科技股份有限公司, 深圳市大族数控科技有限公司 filed Critical 深圳市大族激光科技股份有限公司
Priority to PCT/CN2013/087687 priority Critical patent/WO2015074246A1/zh
Priority to CN201380077672.6A priority patent/CN105324890B/zh
Priority to US15/034,127 priority patent/US9640935B2/en
Publication of WO2015074246A1 publication Critical patent/WO2015074246A1/zh

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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
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/0602—Crystal lasers or glass lasers
    • H01S3/0604—Crystal lasers or glass lasers in the form of a plate or disc
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/001—Axicons, waxicons, reflaxicons
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3066—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state involving the reflection of light at a particular angle of incidence, e.g. Brewster's angle
    • H—ELECTRICITY
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    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/02—Constructional details
    • H01S3/025—Constructional details of solid state lasers, e.g. housings or mountings
    • H—ELECTRICITY
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    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/02—Constructional details
    • H01S3/04—Arrangements for thermal management
    • H01S3/0405—Conductive cooling, e.g. by heat sinks or thermo-electric elements
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    • 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
    • H01S3/02—Constructional details
    • H01S3/04—Arrangements for thermal management
    • H01S3/042—Arrangements for thermal management for solid state lasers
    • H—ELECTRICITY
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    • 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
    • H01S3/08018—Mode suppression
    • H01S3/0804—Transverse or lateral modes
    • H—ELECTRICITY
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    • 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
    • H01S3/08054—Passive cavity elements acting on the polarization, e.g. a polarizer for branching or walk-off compensation
    • H—ELECTRICITY
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    • 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
    • H01S3/08059—Constructional details of the reflector, e.g. shape
    • 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
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    • 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
    • H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
    • H01S3/0941—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a laser diode
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    • 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
    • H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
    • H01S3/0941—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a laser diode
    • H01S3/09415—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a laser diode the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping
    • H—ELECTRICITY
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    • 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
    • H01S3/1601—Solid materials characterised by an active (lasing) ion
    • H01S3/1603—Solid materials characterised by an active (lasing) ion rare earth
    • H01S3/1611—Solid materials characterised by an active (lasing) ion rare earth neodymium
    • H—ELECTRICITY
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    • 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
    • H01S3/1601—Solid materials characterised by an active (lasing) ion
    • H01S3/1603—Solid materials characterised by an active (lasing) ion rare earth
    • H01S3/1618—Solid materials characterised by an active (lasing) ion rare earth ytterbium
    • 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
    • H01S3/164—Solid materials characterised by a crystal matrix garnet
    • H01S3/1643—YAG
    • H—ELECTRICITY
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    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S2301/00—Functional characteristics
    • H01S2301/20—Lasers with a special output beam profile or cross-section, e.g. non-Gaussian
    • H—ELECTRICITY
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    • 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
    • H01S3/02—Constructional details
    • H01S3/04—Arrangements for thermal management
    • H01S3/0407—Liquid cooling, e.g. by water
    • 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
    • H01S3/10061—Polarization control

Definitions

  • This invention relates to lasers, and more particularly to a sheet laser with a gain medium capable of producing a radially polarized laser. Background technique
  • Thin-film lasers are one of the all-solid-state lasers, and they have grown rapidly since Adolf. Giesen et al. first implemented thin-film lasers in 1994.
  • the thin-film laser uses a sheet-like material having a small thickness and a large lateral dimension as a gain medium of the laser, that is, a sheet gain medium.
  • the sheet laser requires heat dissipation from the sheet gain medium during operation.
  • a conventional sheet gain medium cooling device includes a high thermal conductivity copper heat sink attached to the sheet gain medium.
  • a cooling medium microchannel is provided on the copper heat sink.
  • the thin-film laser has the advantages of efficiently deriving thermal deposition in the gain medium and attenuating the thermal lens effect of the gain medium, so that high-power, high-efficiency, high-beam quality laser output can be realized. Since the thin-film laser has the above advantages, it has been widely used in various fields such as defense military, scientific research, and industrial production.
  • the heat applied to the sheet gain medium causes the temperature of the sheet gain medium to be Gaussian, that is, the energy density of the middle portion of the sheet gain medium is high, and the energy density of the portion diffused from the intermediate portion to the periphery gradually decreases.
  • the intermediate portion of the sheet gain medium expands outwardly, forming a "bowl-like" deformation similar to the undercut, which is the thermal lens effect of the sheet laser.
  • the thermal lens effect of the sheet gain medium affects the output power of the laser, the stability of the output laser, and the quality of the laser beam.
  • the sheet gain medium expands and deforms beyond the material's ability to withstand, it may even cause the sheet gain medium to burst.
  • a radially polarized thin-film laser comprising a pump source arranged in a direction along a laser beam path, a collimating lens, a focusing lens, a laser gain medium, a heat dissipating medium, a Brewster biaxial cone, and an output lens, wherein the blues
  • the special biaxial cone includes two opposite cones and a cylinder connecting the two cones, the tapered surface of the cone forming an angle with the bottom surface of a Brewster angle, the laser gain medium and the a heat dissipating medium is bonded, a laser resonator sub-cavity is formed between the laser gain medium and the output lens, and the pump laser light from the pump source passes through the collimating lens and the focusing lens, and is focused on the laser A gain medium, the generated photons oscillate within the laser resonator cavity and ultimately output a radially polarized laser beam from the output lens.
  • the laser gain medium is a Yb:YAG wafer having a doping concentration of 5.0 at% to 15 at% or a Nd:YAG wafer having a doping concentration of 1.0 at% to 5.0 at%,
  • the thickness of the Yb:YAG wafer or the Nd:YAG wafer is 0.2 to 0.5 mm.
  • the heat dissipating medium is made of a YAG crystal, and the heat dissipating medium has a thickness twice that of the laser gain medium.
  • the material of the Brewster biaxial cone is a YAG crystal, and the Brewster angle is 61.2134. ⁇ 2,.
  • the material of the Brewster biaxial cone is quartz, and the Brewster angle is 55.4. ⁇ 2,.
  • the radially polarized thin-film laser further includes a concave mirror group disposed between the laser gain medium and the Brewster biaxial cone, not being The pump laser absorbed by the laser gain medium is reflected by the EJ face mirror group and re-enters the laser gain medium.
  • the EJ face mirror group includes seven inner mirrors and eight outer mirrors, and the seven inner mirrors and the focus lens are arranged to be the Brewster biaxial cone
  • the axis is an inner ring of symmetry axis, and the eight outer mirrors are arranged in an outer ring surrounding the inner ring.
  • the laser gain medium is disposed away from the side of the Brewster biaxial cone with a first two-color optical film that is highly transparent to incident light and highly reflective to the emitted light.
  • a second dichroic optical film having a high permeability to the exiting light and a high permeability to the incident light is provided on a side close to the Brewster biaxial cone.
  • both bottom surfaces of the heat dissipating medium are provided with an exiting light high permeability film.
  • the two tapered faces of the Brewster biaxial cone are each provided with an exiting light permeable membrane.
  • the radially polarized thin-film laser further includes a lens holder, a pump head and a first sealing cover, and the first sealing cover and the pump head cooperate to form a pump for housing the lens holder
  • the cavity mirror is fixed on the lens holder, and the first sealing cover is provided with a coolant circulation system.
  • the radially polarized thin-film laser further includes a heat dissipating device, a second sealing cover, and a cooling device, and one side of the heat dissipating device is provided with a receiving cavity for accommodating the laser gain medium and the heat dissipating medium
  • the second sealing cover is fixedly disposed on the side of the heat dissipating device, the cooling device is in contact with the second sealing cover, and the cooling device and the second sealing cover are respectively provided with a cooling liquid Circulatory system.
  • the cooling device and the second sealing cover are jointly provided with a tapered hole directed to the laser gain medium.
  • the radially polarized thin-film laser further includes an output barrel and a third sealing cover, and one end of the output barrel cooperates with the third sealing cover to form an output mirror cavity, the Brewster A biaxial cone is fixed at one end of the output mirror cavity, the output lens is fixed at the other end of the output mirror cavity, and the third sealing cover is further provided with a coolant circulation system.
  • the pump source emits a pump laser having a wavelength of 940 nm. In one of the embodiments, the radially polarized laser beam has a wavelength of 1030 nm.
  • the bonding of the laser gain medium of the above embodiment to the heat dissipating medium can improve the thermal lens effect of the sheet and stably output the radially polarized laser light.
  • FIG. 1 is a schematic diagram of the principle of a radially polarized thin-film laser of an embodiment
  • FIG. 2 is a cross-sectional view of a radially polarized thin-film laser of an embodiment.
  • FIG. 3 is a perspective exploded view of the radially polarized thin film laser shown in FIG. 2.
  • FIG. 4a is a perspective view of the laser gain medium and the heat dissipating medium shown in FIG. 3.
  • Figure 4b is a cross-sectional view of the Brewster biaxial cone of Figure 3.
  • Figure 5 is a schematic diagram of the propagation path of photons inside and outside the Brewster biaxial cone and laser gain medium.
  • Figure 6 shows the Gaussian mode distribution of the 940 nm pump photon energy.
  • Figure 7 shows the photon energy distribution of a 940nm pump light single-end pump with a length of 10mm Yb:YAG crystal rod pump.
  • Figure 8 is a graph of the absorption function of a 940 nm pump light with a Yb:YAG rod crystal of length 10 mm.
  • Figure 9 shows the pump photon energy distribution for a 940 nm pumped single end pump with a 0.5 mm thick Yb:YAG sheet.
  • Figure 10 is a graph of the absorption function of Yb:YAG flake crystals for 940 nm pump light.
  • Figure 11 is a partial perspective cross-sectional view of the optical resonator.
  • Figure 12 is a schematic cross-sectional view of the EJ mirror group and the pump head.
  • Figure 13 is a perspective exploded view of the concave mirror group and the pump head.
  • Figure 14 is a schematic diagram of the refraction and reflection of plane wave incident air and YAG medium.
  • Figure 15 shows the reflectance of light as it enters YAG from air as a function of incident angle.
  • Figure 16 shows the transmittance of light as it enters YAG from air as a function of incident angle.
  • Figure 18 is a cross-sectional view of the cooling device of the Brewster biaxial cone.
  • Figure 19 is a perspective exploded view of the cooling device shown in Figure 18. detailed description
  • Polarization is one of the most basic features of light, common wired polarized light, elliptically polarized light, circularly polarized light, and radially polarized light. Since the polarization direction of the radially polarized light has a perfect axisymmetric distribution, it has many significantly different characteristics compared to linearly polarized light, circularly polarized light, and elliptically polarized light.
  • the radially polarized light has an electric field distribution symmetric along the optical axis and a hollow circular beam structure; the radially polarized light can produce a very small focal spot beyond the diffraction limit when the high-value lens is focused, than linear polarization, circular polarization
  • the elliptically polarized focused spot is much smaller, and the longitudinal electric field in the focal region becomes very strong; the radially polarized light has only a transverse magnetic field and an electric field along the longitudinal axis; the radially polarized light is the polarization eigenstate, cut in C When propagating into the crystal, crosstalk does not occur.
  • these characteristics of radially polarized light have been used in many applications. As in the process of guiding and capturing particles, accelerating particles, improving the resolution of the microscope, cutting metal, and increasing the density of storage, with the deepening understanding of the radially polarized light, it will be applied in more and more fields. .
  • the radial polarization slice laser 100 of the embodiment includes a pump source 10, a collimator lens 20, a focus lens 30, a laser gain medium 50, and heat dissipation which are sequentially arranged in the direction of the laser beam path.
  • the laser beam output from the pump source 10 is conducted by the optical fiber 12 and passed through the collimating lens 20 and the focusing lens 30 to focus the laser focus on the laser gain medium 50.
  • the generated photons are in the laser gain medium 50 and the output lens 70.
  • the interposed laser resonator cavity 80 oscillates and passes through the Brewster biaxial cone 60 a plurality of times, thereby filtering out photons having a polarization state of P-polarized light, and finally outputting the radially polarized laser beam 90 from the output lens 70.
  • the main function of the pump source 10 is to generate a pump laser as a light source.
  • a laser diode (LD) laser having a wavelength of 940 nm is used as a pump source.
  • the collimating lens 20 is fixed in a collimating lens holder 22 with a cooling water joint 24.
  • the laser gain medium 50 is a Yb:YAG (Yb 3+ :Y 3 Al 5 0i 2 ) circular sheet having a doping concentration of 5.0 at%, and has a thickness of 0.5 mm.
  • the laser gain medium 50 may have a thickness of 0.2 to 0.5 mm and a doping concentration of 5.0 at% to 15 at%.
  • the strong fluorescence peak is located at a weak absorption of the pump energy at a wavelength of 1030 nm, usually the laser output wavelength.
  • the laser gain medium 50 may also be a Nd:YAG sheet having a thickness of 0.2 to 0.5 mm and a doping concentration of 1.0 to 5.0 at%.
  • the pump light emitted from the pump source 10 may have a wavelength of 980 nm and the excited photon has a wavelength of 1064 nm.
  • the heat dissipating medium 55 is shaped like a circular flake similar to the laser gain medium 50.
  • the heat dissipating medium 55 is made of YAG crystal (yttrium aluminum garnet, chemical formula Y 3 A1 5 0 12 ), which is an excellent laser matrix material with stable performance, hard texture, good optical uniformity, and thermal conductivity. High rate, good heat dissipation and so on.
  • the thickness of the heat dissipating medium 55 is twice that of the laser gain medium 50, that is, 1 mm. Since the thickness of the laser gain medium 50 is thin, it is difficult to be clamped by a general mechanical device.
  • the thickness can be increased to facilitate the clamping of the device.
  • the refractive index of the heat dissipating medium 55 and the laser gain medium 50 are the same, and after the bonding, the photons do not have light refraction at the bonding interface of the two circular sheets. Because of the refractive index, light propagates in a straight line, and it is easy to cause photon oscillation and laser light in the laser resonator cavity 80.
  • the material of the Brewster biaxial cone 60 is a YAG crystal comprising two opposing cones 62 and a cylinder 64 connecting the two cones 62.
  • the cone 62 is a cone;
  • the cylinder 64 is a cylinder.
  • the photon of 1030 nm has a refractive index of 1.82 in the YAG crystal.
  • the laser gain medium 50 is separated from the side S1 of the Brewster biaxial cone 60 by a plating film having a first two-color optical film 51 which is highly reflective to the incident light and highly reflective to the outgoing light. Specifically, it is 940nm high reverse, and the incident angle is 32.4268.
  • the purpose of high-reverse 940nm laser light is to re-inject the unabsorbed 940nm wavelength pump light into the laser gain medium 50, then into the thin film pump head, and repeatedly pump the laser gain medium 50 back and forth until the pump light energy It is completely absorbed by the laser gain medium 50.
  • the purpose of the high reversal of the 1030 nm laser is to cause the 1030 nm photon to oscillate back and forth between the S1 surface of the laser gain medium 50 and the output lens 70.
  • the laser gain medium 50 is adjacent to one side of the Brewster biaxial cone 60.
  • the S2 is provided with a second two-color optical film 53 which is highly transparent to the emitted light and highly transparent to the incident light.
  • the second dichroic optical film 53 is specifically a 940 nm high permeability, 1030 nm high transmissive two-color optical film.
  • the 940nm high transmission is to allow the 940nm pump light to be fully pumped through the S2 facing the laser gain medium 50.
  • the 1030nm high transmission is to allow the 1030nm photons that oscillate back and forth to enter the pumping region through the S2 surface to increase the number of photons.
  • the two bottom surfaces S3 and S4 of the heat dissipating medium 55 are plated with a high permeability film of 1030 nm in order to minimize the reflection loss of the 1030 nm photon oscillating and oscillating through the heat dissipating medium 55.
  • the two tapered faces S5, S7 of the Brewster biaxial cone 60 are plated with a highly permeable membrane 62 having a wavelength of 1030 nm equal to the Brewster angle.
  • the goal is to minimize the reflection loss of the 1030 nm parallel component photons oscillating back and forth through the Brewster biaxial cone 60.
  • the cylinder face of the Brewster biaxial cone 60 is S6, which is only for the convenience of clamping and fixing. Since the photons are transmitted inside the Brewster biaxial cone 60, it is not necessary to coat this surface.
  • FIG. 5 shows a schematic diagram of the propagation paths of laser photons within and outside the laser gain medium 50 and the Brewster biaxial cone 60.
  • the Fabry-Perot optical cavity 80 of the S1 plane of the laser gain medium 50 and the output lens 70, the Yb:YAG sheet is the laser gain medium 50, and the Brewster biaxial cone 60 acts in the cavity 80.
  • the 940 nm pump laser emitted from the pump source 10 passes through the collimator lens 20 and the focus lens 30, and focuses the focal spot on the S1 surface of the laser gain medium 50, which is also referred to as a laser pump gain region 52.
  • the 1030 nm photons oscillating back and forth in the cavity 80 will pass through the laser pump gain region 52, and the number of photons will be amplified once each time.
  • the laser will reflect and refract light on the cone S5 of the boundary between the air and the YAG crystal. A part of the vertical component photons (S-polarized light) are lost through the reflection of the cone S5 into the air, and the remaining vertical component Photons (S-polarized light) and all parallel component photons ( ⁇ -polarized light) enter the YAG biaxial cone 16 through the tapered surface S5.
  • the photons (S-polarized light) are respectively reflected on the tapered surfaces S7 and S5 and are lost, while the remaining vertical component photons (S-polarized light) and all parallel component photons (P-polarized light) pass through the Brewster biaxial cone. Body 60, projected in parallel at Brewster's angle. Photons of 1030 nm oscillate back and forth in the optical cavity 80, and each time it oscillates through the Brewster cone 4 times (each through the S5 surface and the S7 surface twice), the loss of the vertical component photons (S-polarized light) is much larger than the parallel component.
  • Photon the light oscillates back and forth through the YAG Brewster biaxial cone 16 multiple times in the cavity 80, eventually causing the loss of the vertical component photons (S-polarized light), and the parallel component (P-polarized light) Due to the amplification of the pump gain region, when the gain of the photon is greater than the loss of the photon in the cavity 80, the laser plane output mirror will be due to the special circular axis symmetry of the Brewster biaxial cone 60. A beam of radially polarized laser light 20 is output.
  • the following cylinders describe the pumping principle of the laser.
  • the laser gain medium 50 used in the present laser is a Yb:YAG sheet having a thickness of 0.5 mm and a doping concentration of 5.0 at%, and an LD laser having a wavelength of 940 nm is used as a pump source.
  • the photon energy distribution of the 940 nm pump light is shown in Fig. 6.
  • the photon distribution of the pump light is Gaussian.
  • the absorption coefficient ⁇ of the 940 nm pump light is 5.6 cm- 1 .
  • Figure 7 shows the pumping photon energy distribution of a 940 nm laser pump with a 10 mm Yb:YAG crystal rod.
  • the corresponding absorption of the pump laser with the length of the Yb:YAG crystal rod is shown in Fig. 8.
  • the photons at 940 nm along the axial direction of the Yb:YAG crystal rod are almost zero, indicating that a 10 mm long Yb:YAG crystal rod is pumped by a laser of 940 nm wavelength, the Yb: The YAG crystal rod can completely absorb the pump energy, and the laser output power of the laser using the laser crystal can be maximized.
  • Figure 9 shows the pump photon energy distribution of a 940 nm pumped single-end pump with a 0.5 mm thick Yb:YAG sheet.
  • the corresponding absorption of the pump laser with the thickness of the Yb:YAG sheet is shown in Figure 10. Shown.
  • ⁇ is the absorption coefficient
  • / is Yb:YAG
  • the thickness of the Yb:YAG sheet affects the absorption rate of the pump light.
  • the absorption of the Yb:YAG sheet with a 940 nm laser pumping thickness of 0.5 mm and a doping concentration of 5.0 at% is 24.42%.
  • the absorption rate of the Yb:YAG sheet having a pump thickness of 1 mm and a doping concentration of 5.0 at% was 42.88%.
  • the pump photons that are not absorbed by the single-pumped sheet are reflected by the one-piece total mirror mounted on the other side, and the sheet-gain medium is again pumped once, for Yb having a thickness of 0.5 mm:
  • the length of the effective pump is approximately the thickness of the sheet.
  • the pump light absorption rate is 42.88%, and more than half (57.12%) of the pump energy is not absorbed.
  • the concave mirror group 40 includes seven inner mirrors 41 and eight outer mirrors 43.
  • the seven inner mirrors 41 and the focus lens 30 are arranged in an inner ring having an axis of symmetry of the axis of the Brewster biaxial cone 60.
  • the eight outer mirrors 43 are arranged in an outer ring surrounding the inner ring.
  • the pumping laser source 10 focuses the focus on the laser gain medium 50 through the focusing lens 30, and the unabsorbed pump light is totally reflected by the S2 plane of the laser gain medium 50 into the air, which is 15 of the concave mirror group 40.
  • the concave mirror is reflected back to the laser gain medium 50 in turn.
  • the absorption rate of the Puguang thereby achieving the output of a high power radially polarized laser beam. It will be appreciated that the concave mirror set 40 can also be omitted.
  • the radial polarization sheet laser 100 of the present embodiment further includes a lens holder 42, a first pump head 44 and a first sealing cover 46.
  • the first sealing cover 46 is generally disc-shaped, and the first pump head 44 is substantially in the shape of a hollow cone that cooperates with the first sealing cover 46.
  • the first sealing cover 46 and the first pump head 44 cooperate to form a pumping chamber 48 for housing the lens holder 42.
  • the lens holder 42 is roughly a two-layered disk, and the concave mirror group 40 is fixed to the lens holder 42.
  • the seven inner mirrors 42 and the focus lens 30 are arranged on the inner circumference of the lens holder 42, and the eight outer mirrors 44 are arranged on the outer circumference of the lens holder 42.
  • a passage 462 is formed between the first seal cover 46 and the lens holder 42 for the passage of the cooling water.
  • the first sealing cover 46 is further provided with a water inlet pipe joint 464 and an outlet pipe joint 466 connected to the passage 462, thereby forming a coolant circulation system.
  • R +T 1 (4) where 7 is the transmittance of the parallel component, ⁇ is the transmittance of the vertical component, R
  • the reflectivity which is the reflectance of the vertical component, is the angle of incidence of the light incident on the surface of the axicon, which is the angle of refraction into which the light is refracted into the axicon.
  • the 940 nm pumping light source focuses the spot on the laser gain medium 50 through the focusing lens 30, since the laser gain medium 50 A Fabry-Perot optical cavity is formed between the output lens 70 and the laser gain medium 50 is pump-excited to emit photons of 1030 nm wavelength in all directions centered on the pumping region (pumping light focal spot) 52.
  • the photons along the propagation path of the photon in the laser cavity between the Brewster biaxial cone 60 and the laser gain medium 50 as shown in FIG. 5 can oscillate back and forth in the laser resonator cavity 80, and the photons in other propagation directions are not It is suppressed by the condition of oscillating back and forth in the cavity.
  • the photon passes through the Brewster biaxial cone 60 times, and passes through the Brewer cone twice.
  • photons are incident from the air at the Brewster angle in parallel to the cone S5 into the Brewster biaxial cone 60.
  • the cone S5 reflects off a portion of the vertical component photons into the air, while the partial vertical component photons and all the parallel component photons are from Air enters the YAG crystal.
  • the second time is that photons are emitted from the cone surface S7 of the Brewster biaxial cone 60 in parallel with the Brewster angle into the air.
  • the cone surface S7 reflects a part of the vertical component photons into the Brewster biaxial cone 60, and the part Vertical component photons and all parallel component photons are refracted from the Brewster biaxial cone 60 into the air. Therefore, when a photon passes through the Brewster biaxial cone 60, the vertical component photons (S-polarized light) are lost in the Brewster cone (S5 and S7 planes) by reflection, and some of the vertical component photons (S-polarized light) And all parallel component photons (P-polarized light) are emitted in parallel from the Brewster biaxial cone 60 into the air.
  • a heat sink may be mounted on the pump side of the laser gain medium 50.
  • the laser gain medium 50 generates a large amount of heat to be cooled by water cooling of the heat sink.
  • the radially polarized thin-film laser 100 of the present embodiment further includes a heat sink 54, a second seal cover 56, and a cooling device 58.
  • the material of the heat sink 54 is copper.
  • One side of the heat sink 54 is provided with a receiving cavity 542 for accommodating the laser gain medium 50 and the heat dissipating medium 55, and the other side is provided with a strip structure 544 for increasing the heat dissipating area.
  • a coolant circulation system 546 is also provided inside the heat sink 54.
  • the second sealing cover 56 is substantially annular and has a coolant circulation system 562 therein.
  • the second seal cover 56 is fixed to one side of the heat sink 54 by screws.
  • the cooling device 58 is generally a hollow cylinder having a plurality of fins 582 on its surface.
  • the cooling device 58 is attached to the second sealing cover 56.
  • the material of the cooling device 58 is also copper.
  • the cooling device 58 and the second sealing cover 56 collectively begin to have a tapered bore 584 directed toward the laser gain medium 50 to facilitate focusing of the focusing lens 30 to better focus the pumping energy onto the laser gain medium 50.
  • the laser gain medium 50 When the laser gain medium 50 is pumped by a high power 940 nm pump source, the laser gain medium 50 absorbs a large amount of pump energy, which generates a large amount of heat, which passes through the heat sink 54, the heat sink medium 55, and the coolant circulation system.
  • the 546 and the coolant circulation system 562 perform circulating water cooling to remove a large amount of heat in time to protect the laser gain medium 50 from thermal stress cracking and coating from falling off.
  • a high-power pump source is used to pump the laser gain medium 50.
  • the high-energy oscillating photon passes through the Brewster biaxial cone 60, a large amount of heat is generated, which generates a thermal lens effect, which causes the laser output mode to change. Poor, therefore, the Brewster biaxial cone 60 needs to be dissipated.
  • the radially polarized thin-film laser 100 of the present embodiment further includes an output barrel 76 and a third sealing cover 78.
  • the output barrel 76 is substantially a hollow cylinder having a ring of fins 762 on its surface. One end of the output barrel 76 cooperates with the third sealing cover 78 to form an output mirror cavity 73.
  • the Brewster biaxial cone 60 is secured to one end of the output mirror cavity 73 by a cone compression ring 74.
  • the other end of the output barrel 76 is fixedly coupled to the first sealing cover 46 by a tapered second pump head 49 (see Fig. 11).
  • the output lens 70 is fixed to the other end of the output mirror cavity 73 by a lens press ring 72.
  • a coolant circulation system 782 is also disposed on the third seal cover 78.

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Abstract

一种径向偏振薄片激光器，包括沿激光光路方向上依次排列的泵浦源（10）、准直透镜（20）、聚焦透镜（30）、激光增益介质（50）、散热介质（55）、布鲁斯特双轴锥体（60）及输出透镜（70）。布鲁斯特双轴锥体（60）包括两个相对的锥体和连接两个锥体的柱体，锥体的锥面（S5，S7）与底面形成的夹角为布鲁斯特角。激光增益介质（50）与散热介质（55）相键合。激光增益介质（50）与输出透镜（70）之间形成激光谐振子腔。泵浦源（10）发出的泵浦激光经过准直透镜（20）和聚焦透镜（30）后，聚焦于激光增益介质（50），产生的光子在激光谐振子腔内振荡，并最终从输出透镜（70）输出径向偏振激光束。

Description

说明书
发明名称： 径向偏振薄片激光器 技术领域
本发明涉及激光器， 特别是涉及一种带有增益介质的能够产生径向偏振 激光的薄片激光器。 背景技术
薄片激光器是全固态激光器中的一种， 自 Adolf. Giesen等人 1994年首次 实现薄片激光器以来， 其得到了迅速发展。 薄片激光器采用厚度很小而横向 尺寸较大的薄片状材料作为激光器的增益介质， 即薄片增益介质。 薄片激光 器工作时需要对薄片增益介质进行散热。 传统的薄片增益介质的冷却装置包 括附着于薄片增益介质上的高热导率的紫铜热沉。 紫铜热沉上设置有冷却介 质微通道。 由于薄片增益介质的面积很大、 厚度很小， 因此增益介质上的热 量可以快速、 有效的通过紫铜热沉传递给冷却介质微通道， 再由冷却介质带 走。 薄片激光器具有可以高效导出增益介质内的热沉积、 减弱增益介质的热 透镜效应等优点， 因此可以实现高功率、 高效率、 高光束质量的激光输出。 由于薄片激光器具有上述优点， 因此已广泛应用于国防军事、 科学研究、 工 业生产等各个方面。
但是薄片激光器工作时， 加载到薄片增益介质上的热量使得薄片增益介 质的温度成高斯分布， 即薄片增益介质中间部分的能量密度较高， 从中间部 分向四周扩散的部分的能量密度逐渐降低。 从而导致薄片增益介质中间部分 向外膨胀较大， 形成类似倒扣的 "碗状" 变形， 此即薄片激光器的热透镜效 应。 当薄片激光器高功率运行时， 薄片增益介质的热透镜效应会影响激光器 的输出功率、 输出激光的稳定性及激光光束质量。 当薄片增益介质膨胀变形 超过材料的承受能力， 甚至会导致薄片增益介质炸裂。 发明内容
基于此， 有必要提供一种改善热透镜效应、 提高输出稳定性的径向偏振 薄片激光器。
一种径向偏振薄片激光器， 包括沿激光光路方向上依次排列的泵浦源、 准直透镜、 聚焦透镜、 激光增益介质、 散热介质、 布鲁斯特双轴锥体及输出 透镜， 其中， 所述布鲁斯特双轴锥体包括两个相对的锥体和连接所述两个锥 体的柱体， 所述锥体的锥面与底面形成的夹角为布鲁斯特角， 所述激光增益 介质与所述散热介质相键合， 所述激光增益介质与所述输出透镜之间形成激 光谐振子腔， 所述泵浦源发出的泵浦激光经过所述准直透镜和聚焦透镜后， 聚焦于所述激光增益介质， 产生的光子在所述激光谐振子腔内振荡， 并最终 从所述输出透镜输出径向偏振激光束。
在其中一个实施例中， 所述激光增益介质为掺杂浓度为 5.0at%~15at%的 Yb:YAG圆片或掺杂浓度为 1.0at%~5.0at%的 Nd:YAG圆片， 所述 Yb:YAG圆 片或 Nd:YAG圆片的厚度为 0.2~0.5mm。
在其中一个实施例中， 所述散热介质的材料为 YAG晶体， 所述散热介质 的厚度为所述激光增益介质的两倍。
在其中一个实施例中， 所述布鲁斯特双轴锥体的材料为 YAG晶体， 所述 布鲁斯特角为 61.2134。 ± 2，。
在其中一个实施例中， 所述布鲁斯特双轴锥体的材料为石英， 所述布鲁 斯特角为 55.4。 ± 2，。
在其中一个实施例中， 所述径向偏振薄片激光器还包括凹面反射镜组， 所述凹面反射镜组设置在所述激光增益介质与所述布鲁斯特双轴锥体之间， 未被所述激光增益介质吸收的泵浦激光经所述 EJ面反射镜组反射后， 重新进 入所述激光增益介质。
在其中一个实施例中， 所述 EJ面反射镜组包括七片内反射镜和八片外反 射镜， 所述七片内反射镜与所述聚焦透镜排列成以所述布鲁斯特双轴锥体的 轴线为对称轴的内圆环， 所述八片外反射镜排列成一个环绕所述内圆环的外 圆环。
在其中一个实施例中， 所述激光增益介质远离所述布鲁斯特双轴锥体的 一面设有对入射光高透、 对出射光高反的第一双色光学膜， 所述激光增益介 质靠近所述布鲁斯特双轴锥体的一面设有对出射光高透、 对入射光高透的第 二双色光学膜。
在其中一个实施例中， 所述散热介质的两个底面均设有出射光高透膜。 在其中一个实施例中， 所述布鲁斯特双轴锥体的两个锥面分别设有出射 光高透膜。
在其中一个实施例中， 所述径向偏振薄片激光器还包括透镜座、 泵浦头 及第一密封盖， 所述第一密封盖和所述泵浦头配合形成一个收容所述透镜座 的泵浦腔， 所述凹面反射镜组固定在所述透镜座上， 所述第一密封盖内设有 冷却液循环系统。
在其中一个实施例中， 所述径向偏振薄片激光器还包括散热装置、 第二 密封盖及冷却装置， 所述散热装置的一侧开设有容纳所述激光增益介质和所 述散热介质的收容腔， 所述第二密封盖固定设置在所述散热装置的该侧， 所 述冷却装置与所述第二密封盖相贴合， 所述散热装置和所述第二密封盖上均 设有冷却液循环系统。
在其中一个实施例中， 所述冷却装置和所述第二密封盖上共同开设有指 向所述激光增益介质的锥形孔。
在其中一个实施例中， 所述径向偏振薄片激光器还包括输出镜筒和第三 密封盖， 所述输出镜筒的一端与所述第三密封盖相配合形成输出镜腔， 所述 布鲁斯特双轴锥体被固定在所述输出镜腔的一端， 所述输出透镜固定在所述 输出镜腔的另一端， 所述第三密封盖上还设有冷却液循环系统。
在其中一个实施例中， 所述泵浦源发出的泵浦激光的波长为 940nm。 在其中一个实施例中， 所述径向偏振激光束的波长为 1030nm。
上述实施例的激光增益介质与散热介质的键合， 能够改善薄片的热透镜 效应， 并能稳定地输出径向偏振的激光。 附图说明
通过附图中所示的本发明的优选实施例的更具体说明， 本发明的上述及 其它目的、 特征和优势将变得更加清晰。 在全部附图中相同的附图标记指示 相同的部分， 且并未刻意按实际尺寸等比例缩放绘制附图， 重点在于示出本 发明的主旨。
图 1为一实施例的径向偏振薄片激光器的原理示意图；
图 2为一实施例的径向偏振薄片激光器的剖视图。
图 3为图 2所示径向偏振薄片激光器的立体分解示意图。
图 4a为图 3所示激光增益介质和散热介质的立体示意图。
图 4b为图 3布鲁斯特双轴锥体的剖面示意图。
图 5 为光子在布鲁斯特双轴锥体与激光增益介质内外的传播路径示意 图。
图 6为 940nm泵浦光光子能量高斯模式分布图。
图 7为 940nm泵浦光单次端泵长度为 10mmYb:YAG晶体棒泵浦光子能 量分布图。
图 8为长度为 10mm的 Yb:YAG棒状晶体对 940nm泵浦光的吸收函数图。 图 9为 940nm泵浦光单次端泵 0.5mm厚的 Yb:YAG薄片时泵浦光子能量 分布图。
图 10为 Yb:YAG薄片晶体对 940nm泵浦光的吸收函数图。
图 11为光学谐振腔的局部立体剖视图。
图 12为 EJ面反射镜组和泵浦头的剖面示意图。
图 13为凹面反射镜组和泵浦头的立体分解示意图。
图 14为平面波入射空气与 YAG介质的折射与反射示意图。
图 15显示了光从空气进入 YAG时的反射率随入射角 的变化曲线。 图 16显示了光从空气进入 YAG时的透射率随入射角 的变化曲线。 图 18为布鲁斯特双轴锥体的冷却装置的剖视图。
图 19为图 18所示的冷却装置的立体分解示意图。 具体实施方式
为使本发明的上述目的、 特征和优点能够更加明显易懂， 下面结合附图 对本发明的具体实施方式做详细的说明。 在下面的描述中阐述了很多具体细 节以便于充分理解本发明。 但是本发明能够以很多不同于在此描述的其它方 式来实施， 本领域技术人员可以在不违背本发明内涵的情况下做类似改进， 因此本发明不受下面公开的具体实施的限制。
需要说明的是， 当元件被称为 "固定于" 另一个元件， 它可以直接在另 一个元件上或者也可以存在居中的元件。 当一个元件被认为是 "连接" 另一 个元件， 它可以是直接连接到另一个元件或者可能同时存在居中元件。
除非另有定义， 本文所使用的所有的技术和科学术语与属于本发明的技 术领域的技术人员通常理解的含义相同。 本文中在本发明的说明书中所使用 的术语只是为了描述具体的实施例的目的， 不是旨在于限制本发明。 本文所 使用的术语 "及 /或" 包括一个或多个相关的所列项目的任意的和所有的组 合。
偏振是光的最基本的特征之一， 常见的有线偏振光、 椭圆偏振光、 圆偏 振光以及径向偏振光。 由于径向偏振光的偏振方向具有完美的轴对称分布几 何特性， 使得它与线偏振光、 圆偏振光和椭圆偏振光相比有着很多显著不同 的特性。 如径向偏振光具有沿光轴对称的电场分布以及中空的圆环形的光束 结构； 径向偏振光在高数值透镜聚焦时可以产生超越衍射极限的极小焦斑， 比线偏振、 圆偏振、 椭圆偏振的聚焦光斑小的多， 而且在焦点区域的纵向电 场变的非常强； 径向偏振光只有横向的磁场和沿轴纵向的电场； 径向偏振光 是偏振本征态， 在 C切向晶体中传播时， 不会发生串扰。 近年来， 径向偏振 光的这些特性得到了很多的应用。 如在引导和捕捉粒子、 粒子加速、 提高显 微镜的分辨率、 金属切割以及提高存储密度等方面， 随着人们对径向偏振光 的不断深入的认识， 它将在越来越多的领域得到应用。
请参阅图 1、 图 2及图 3 , —实施例的径向偏振薄片激光器 100包括沿激 光光路方向上依次排列的泵浦源 10、 准直透镜 20、 聚焦透镜 30、 激光增益 介质 50、 散热介质 55、 布鲁斯特双轴锥体 60及输出透镜 70。 泵浦源 10输 出的激光光束由光纤 12传导并通过准直透镜 20、 聚焦透镜 30, 将激光焦点 聚焦于激光增益介质 50上，产生的光子在激光增益介质 50与输出透镜 70之 间形成的激光谐振子腔 80 内振荡， 并多次经过布鲁斯特双轴锥体 60, 从而 筛选出偏振状态为 P偏振光的光子，最终从输出透镜 70输出径向偏振激光束 90。
泵浦源 10的主要作用是作为光源产生泵浦激光。 本实施例中， 采用波长 为 940nm的激光二极管 （ LD )激光器作为泵浦源。
准直透镜 20固定在带有冷却水接头 24的准直透镜座 22内。
请参阅图 4a, 在本实施例中， 激光增益介质 50为掺杂浓度为 5.0at%的 Yb:YAG ( Yb3+:Y3Al50i2 ) 圆形薄片， 其厚度为 0.5mm。 在其他实施例中， 激 光增益介质 50的厚度也可以为 0.2~0.5mm, 掺杂浓度可以为 5.0at%~15at%。 Yb3+离子的主吸收峰有两个， 分别位于 938nm和 970nm。 在 938nm处， 具有 长达 18nm的吸收带宽， 可作为激光二极管泵浦的泵浦带。 强的荧光峰位于 1030nm波长的泵浦能量弱吸收处， 通常为激光输出波长。 在其他实施例中， 激光增益介质 50 也可以是 Nd:YAG 薄片， 其厚度 0.2~0.5mm, 掺杂浓度 1.0~5.0at%。 此时， 泵浦源 10发出的泵浦光的波长可以为 980nm, 激发的光 子的波长为 1064nm。
在本实施例中， 散热介质 55的形状为与激光增益介质 50相似的圆形薄 片。 散热介质 55的材料为 YAG晶体（钇铝石榴石， 化学式为 Y3A15012 ), 其 是一种极好的激光基质材料， 具有性能稳定、 质地坚硬、 光学各相同性好、 热导率高， 散热性能好等优点。 散热介质 55的厚度为激光增益介质 50的两 倍， 即为 lmm。 由于激光增益介质 50的厚度较薄， 难以采用一般的机械设 备夹持， 因此， 将散热介质 55与激光增益介质 50键合后， 可以增大厚度， 方便设备夹持。 另外， 与普通光学玻璃不同的， 散热介质 55和激光增益介质 50的折射率是相同的， 键合之后， 光子在这两片圆形薄片的键合分界面上不 会出现光的折射现象， 因折射率一样， 光是沿直线传播的， 在激光谐振子腔 80内较易引起光子的振荡并产生激光。
请参阅图 4b,在本实施例中，布鲁斯特双轴锥体 60的材料为 YAG晶体， 其包括两个相对的锥体 62和连接两个锥体 62的柱体 64。 本实施例中， 锥体 62为圆锥体；柱体 64为圆柱体。 1030nm的光子在 YAG晶体的折射率为 1.82。 锥体 62 的锥面与底面形成的夹角为布鲁斯特角， 即 Θ Β=61.2134° 。 在其他 实施例中，布鲁斯特双轴锥体 60也可以采用熔融石英材料，由于其对 1030nm 的波长的光的折射率为 1.45 , 通过计算其布鲁斯特角 Θ Β=55.4。 。
在本实施例中，激光增益介质 50远离布鲁斯特双轴锥体 60的一面 S1上 通过镀膜设有对入射光高反、 对出射光高反的第一双色光学膜 51。 具体为 940nm高反、 以入射角为 Θ尸32.4268。 的 1030nm高反的第一双色光学膜。 对 940nm的激光高反的目的是让未被吸收完的 940nm波长的泵浦光反射再次 进入激光增益介质 50,然后进入薄片泵浦头，反复来回泵浦激光增益介质 50, 直至泵浦光能量完全被激光增益介质 50吸收。 对 1030nm的激光高反的目的 则是让 1030nm的光子在激光增益介质 50的 S1面与输出透镜 70之间形成的 法布里 -珀罗激光谐振子腔 80来回振荡。
激光增益介质 50靠近布鲁斯特双轴锥体 60的一面 S2通过镀膜设有对出 射光高透、 对入射光高透的第二双色光学膜 53。 第二双色光学膜 53具体为 940nm高透、 1030nm高透的双色光学膜。 940nm高透是为了让 940nm的泵 浦光通过 S2面对激光增益介质 50完全进行有效地泵浦。 1030nm高透则是为 了让来回振荡的 1030nm光子能够透过 S2面进入泵浦区域使其光子数得到放 大。
散热介质 55的两个底面 S3、 S4上均镀有 1030nm的高透膜， 目的是尽 量减少来回振荡的 1030nm光子在经过散热介质 55时的反射损耗。
布鲁斯特双轴锥体 60的两个锥面 S5、 S7均镀有以入射角等于布鲁斯特 角的 1030nm波长的高透膜 62。 目的是尽量减少来回振荡的 1030nm的平行 分量光子在经过布鲁斯特双轴锥体 60时的反射损耗。 布鲁斯特双轴锥体 60 的柱面 S6为毛面，仅为方便夹持和固定之用， 因光子均在布鲁斯特双轴锥体 60的里面传输， 无需对此面进行镀膜。
图 5示出了激光光子在激光增益介质 50与布鲁斯特双轴锥体 60内外的 传播路径示意图。 激光增益介质 50的 S1面与输出透镜 70构成的法布里-珀 罗光学谐振腔 80, Yb:YAG薄片为激光增益介质 50, 而布鲁斯特双轴锥体 60 则在谐振腔 80内起着抑制垂直分量光子（S偏振光）， 选出平行分量光子（P 偏振光） 并让其在谐振腔 80内起振的作用。
泵浦源 10发出的 940nm的泵浦激光通过准直透镜 20、 聚焦透镜 30后， 将焦斑聚焦于激光增益介质 50的 S1面上，焦斑也称之为激光泵浦增益区 52。 来回振荡于谐振腔 80的 1030nm的光子都将经过这个激光泵浦增益区 52 ,每 经过一次， 其光子数量将被放大一次。
940nm 波长的激光经过激光泵浦增益区 52 的泵浦之后会被激发成 1030nm的激光平行射出散热介质 55 , 并以布鲁斯特角 （ Θ Β=61.2134。 ）从 空气平行入射到布鲁斯特双轴锥体 60。 激光在空气与 YAG晶体分界的锥面 S5上会发生光的反射和折射现象， 一部分垂直分量光子 （S偏振光）通过在 锥面 S5的反射进入空气中被损耗掉， 而剩下的垂直分量光子（S偏振光）和 全部平行分量光子 （ Ρ偏振光 ) 则透过锥面 S5进入到 YAG双轴锥体 16里。 这些光子在布鲁斯特双轴锥体 60里是沿直线传播，垂直分量光子（ S偏振光 ) 和平行分量光子 （Ρ偏振光）在比例上维持不变。 当这些光子通过布鲁斯特 双轴锥体 60的锥面 S7时， 会在布鲁斯特双轴锥体 60与空气的分界面 S7发 生光的反射与折射， 一部分垂直分量光子（S偏振光）通过 S7面的反射到布 鲁斯特双轴锥体 60而损耗掉， 余下的垂直分量光子（ S偏振光）和全部平行 分量光子 （Ρ偏振光）通过布鲁斯特双轴锥体 60的锥面 S7以布鲁斯特角平 行射到空气中。 在空气中， 这些光子沿直线传播入射到输出透镜 70, 输出透 镜 70将这些光子按原路返回以布鲁斯特角再一次进入布鲁斯特双轴锥体 60, 依次经过锥面 S7、 S5 , 垂直分量的光子 （S偏振光）会分别在锥面 S7、 S5 发生反射而损耗掉， 而余下的垂直分量光子 （S 偏振光）和全部平行分量光 子（P偏振光）则透过布鲁斯特双轴锥体 60,以布鲁斯特角平行射出。 1030nm 的光子在光学谐振腔 80来回振荡， 每振荡一次要经过布鲁斯特锥面 4次（各 通过 S5面、 S7面两次）， 垂直分量的光子 （S偏振光） 的损耗要远大于平行 分量的光子（ P偏振光）， 光在谐振腔 80中来回振荡多次经过 YAG布鲁斯特 双轴锥体 16, 最终使垂直分量的光子（ S偏振光）损失殆尽， 而平行分量（ P 偏振光）因经过泵浦增益区得到放大， 当光子的增益大于光子在谐振腔 80内 的损耗时， 因布鲁斯特双轴锥体 60特殊的圆轴对称结构， 激光平面输出镜将 输出一束径向偏振激光 20。
以下筒要描述本激光器的泵浦原理。
本激光器使用的激光增益介质 50是厚度为 0.5mm、掺杂浓度为 5.0at%的 Yb:YAG薄片， 采用波长为 940nm的 LD激光器作为泵浦源。 940nm泵浦光 光子能量分布如图 6所示， 泵浦光的光子分布呈高斯模式分布。
使用 940nm的激光器对激光增益介质 50进行泵浦时， Yb:YAG激光晶体 作为增益介质会吸收泵浦能量， 吸收函数为; 7。 = l-exp(«*/)， 为吸收系数， / 为 Yb:YAG薄片的厚度或 Yb:YAG晶体棒的长度。 对于掺杂浓度为 5.0at%的 Yb:YAG薄片， 940nm泵浦光的吸收系数 α为 5.6cm-1。
图 7示出了 940nm激光器泵浦长度为 10mmYb:YAG晶体棒泵浦光子能 量分布图， 与其相对应的泵浦激光吸收量随 Yb:YAG晶体棒的长度的吸收函 数如图 8所示。 从图 7、 8可以看到， 沿 Yb:YAG晶体棒的轴向 10mm处的 940nm的光子几乎为零， 表明采用 940nm波长的激光器单次泵浦 10mm长的 Yb:YAG晶体棒， 该 Yb:YAG晶体棒可以将泵浦能量全部吸收， 可以达到采 用该激光晶体的激光器的激光输出功率最大化。
图 9示出了 940nm泵浦光单次端泵 0.5mm厚的 Yb:YAG薄片时泵浦光子 能量分布图， 与其相对应的泵浦激光吸收量随 Yb:YAG薄片厚度的吸收函数 如图 10所示。 图 9、 10可以看到， 采用 940nm激光器泵浦厚度为 0.5mm的 Yb:YAG薄片时，按照吸收函数为 ηα = l- exp(« * /) , α为吸收系数， /为 Yb:YAG 薄片的厚度， 单次泵浦薄片对泵浦能量吸收 77。 = l- exp(« */) =l-exp ( -0.56*0.5 ) =24.42%, 所以还有 75.58%的泵浦能量未被吸收。 从 940nm光子在单次泵浦 薄片时其光子分布可以明显看到大部分的泵浦光子未被吸收。 图 10 可以看 到， Yb:YAG薄片的厚度会影响泵浦光对其的吸收率， 940nm激光器泵浦厚 度为 0.5mm、掺杂浓度为 5.0at%的 Yb:YAG薄片的吸收率为 24.42%, 而泵浦 厚度为 lmm、 掺杂浓度为 5.0at%的 Yb:YAG薄片的吸收率为 42.88%。
按照传统的薄片激光器的泵浦方式， 即单次泵浦薄片未被吸收的泵浦光 子经过另外一侧安装的一片全反射镜反射回来再度泵浦薄片增益介质一次， 对于厚度 0.5mm的 Yb:YAG薄片来说， 通过有效泵浦的长度约为薄片厚度的 两倍， 即 1mm, 其泵浦光的吸收率为 42.88%, 有超过一半（57.12% ) 的泵 浦能量未被吸收。 要提高径向偏振激光器的激光功率输出， 就必须提高泵浦 激光器能量的吸收。
为了提高吸收率， 在本实施例中， 在激光增益介质 50与布鲁斯特双轴锥 体 60之间还增设了 15片内镀 940nm高反膜的凹面反射镜组 40。 请参阅图 11 , 凹面反射镜组 40包括七片内反射镜 41和八片外反射镜 43。 七片内反射 镜 41与聚焦透镜 30排列成以布鲁斯特双轴锥体 60的轴线为对称轴的内圆 环。 八片外反射镜 43排列成一个环绕所述内圆环的外圆环。 泵浦激光源 10 通过聚焦透镜 30, 将焦点聚焦于激光增益介质 50上， 未被吸收的泵浦光被 激光增益介质 50的 S2面全反射进入到空气中， 被凹面反射镜组 40的 15片 凹面反射镜依次反射回激光增益介质 50, 采用这种泵浦结构 （1 片聚焦透镜 +15片反射镜）， 泵浦光将有 31次（=15*2+1 ) 泵浦 0.5mm厚的薄片， 其泵 浦有效长度近似为 31 *0.5=15.5mm, J^J泵浦光的吸收；；。 = l- exp(a */) =l-exp ( -0.56*15.5 ) =99.98%, 则说明泵浦光几乎完全被 5.0at%的 Yb:YAG薄片吸 收， 极大地提高了激光增益介质对泵浦光的吸收率， 从而实现大功率径向偏 振激光光束的输出。 可以理解， 凹面反射镜组 40也可省略。
为了防止高能量的泵浦对光学镜片带来损伤， 因此需要对凹面反射镜组 40进行散热处理。 请同时参阅图 12和图 13 , 本实施例的径向偏振薄片激光 器 100还包括透镜座 42、 第一泵浦头 44及第一密封盖 46。 第一密封盖 46大 致呈圆盘形， 第一泵浦头 44的形状大致为与第一密封盖 46相配合的空心锥 体。 第一密封盖 46和第一泵浦头 44配合形成一个收容透镜座 42的泵浦腔 48。透镜座 42大致为一个两层的圆盘，凹面反射镜组 40固定在透镜座 42上。 具体的， 七片内反射镜 42与聚焦透镜 30排列在透镜座 42的内圈， 八片外反 射镜 44排列在透镜座 42的外圈。 第一密封盖 46与透镜座 42之间形成供冷 却水流通的通道 462。 第一密封盖 46上还设有与该通道 462相连的进水管接 头 464和出水管接头 466 , 由此组成一个冷却液循环系统。
以下对径向偏振光的产生进行进一步说明。
众所周知， 光属于电磁波， 如图 14 所示， 光作为平面波， 入射空气与 图 14中 S(i)为入射光， SW 为反射光， S(t)为透射光。 布鲁斯特双轴锥体 60的材质为 YAG晶体， 相对于 1030nm波长的光子， 其折射率按 1.82计算。 根据菲尼尔公式得出的光从空 气进入 YAG或 Nd: YAG介质发生折射和反射时的透射率和反射率的公式如 下所示：
tan2(^.-^)
R (1) tan2(^. +^) sin2
R (2) sin2(^.+^)
R„+T„=l (3)
R +T =1 (4) 其中， 7；为平行分量的透射率， ±为垂直分量的透射率， R
的反射率， 为垂直分量的反射率， 为光入射轴锥体表面的入射角， 为 光折射进入轴锥体的折射角。
当光子以入射角 从空气入射到 YAG晶体，会发生光子的反射和折射现 象， 其折射角为 et, 其平行分量和垂直分量的反射率分别是 R//= tan 2 2^ _ 和 tan2( + ）
= sin2(「 )。 当光子以入射角等于 θί从 YAG晶体入射到与空气的分界面， sin (^+0t) 同样会发生光子的反射和折射现象， 折射角为 。 上面两个现象的本质上是 光路可逆， 入射角 与折射角 et互易， 所以， 平行分量和垂直分量的反射率 仍然分别是 R 2( _ )和 sin _ ）。
tan2(^.+^) sin2(^.+^) 当光子以布鲁斯特角 ΘΒ=61.2134。 从空气平行入射到 YAG晶体时， 由 公式（1) 、 （2) 、 （3) 、 （4)计算（反射率和透射率的函数曲线如图 15、 图 16所示） ， 垂直分量的反射率为 28.75%、 透射率为 71.25%, 平行分量的 反射率为 0, 透射率为 1, 无反射损失， 即部分垂直分量和全部平行分量从空 气进入 YAG晶体。当光子以布鲁斯特角 ΘΒ=61.2134。 从 YAG晶体平行入射 到空气中时， 折射角为布鲁斯特角 Θ Β=61.2134° , 入射角与折射角互易， 由 公式（1 ) 、 （2 ) 、 （3 ) 、 （4 )计算可得知： 垂直分量的反射率为 28.75%, 透射率为 71.25%, 平行分量的反射率为 0, 透射率为 1 , 无反射损失， 即部 分垂直分量和全部平行分量从 YAG晶体进入空气中。 意图， 其中， " · " 表示垂直分量光子即 S偏振光， "Γ 表示平行分量光子 即 Ρ偏振光。 940nm的泵浦光源通过聚焦透镜 30将光斑聚焦于激光增益介质 50,由于激光增益介质 50与输出透镜 70之间构成了法布里 -珀罗光学谐振腔， 激光增益介质 50受泵浦激发以泵浦区域（泵浦光焦斑） 52为中心向各个方 向发射 1030nm波长的光子。 只有沿着如图 5所示的激光谐振腔内光子在布 鲁斯特双轴锥体 60与激光增益介质 50内外的传播路径的光子才能在激光谐 振子腔 80内来回振荡，其他传播方向的光子因不具备在腔体内来回振荡的条 件而被抑制掉。
通过上面的讨论， 光子经过布鲁斯特双轴锥体 60—次时， 有两次经过布 鲁斯特锥面。第一次是光子从空气以布鲁斯特角平行入射到锥面 S5进入布鲁 斯特双轴锥体 60, 锥面 S5会反射掉一部分垂直分量光子进入空气， 而部分 垂直分量光子和全部平行分量光子从空气进入到 YAG晶体中去。第二次则是 光子从布鲁斯特双轴锥体 60的锥面 S7以布鲁斯特角平行射出到空气中， 锥 面 S7会反射掉一部分垂直分量的光子进入布鲁斯特双轴锥体 60, 而部分垂 直分量光子和全部平行分量光子从布鲁斯特双轴锥体 60折射到空气中去。所 以， 光子经过布鲁斯特双轴锥体 60时， 垂直分量光子（ S偏振光）在布鲁斯 特锥面（ S5面和 S7面 )则通过反射会损耗掉一部分， 部分垂直分量光子（ S 偏振光）和全部平行分量光子（P偏振光）从布鲁斯特双轴锥体 60平行射出 到空气中。
为了改善径向本激光器的激光增益介质 50的热透镜效应，需要将 940nm 的泵浦源 10泵浦激光增益介质 50时产生大量的热及时散掉。由于 YAG晶体 是热的良好导体， 通过将散热介质 55与激光增益介质 50进行键合， 能够有 效改善激光增益介质 50的热透镜效应， 提高激光输出模式质量。 更进一步， 在本实施例中， 为了更有效地保护激光增益介质 50、 布鲁斯 特双轴锥体 60和改善激光增益介质 50的热透镜效应， 可以在激光增益介质 50的泵浦侧安装散热装置， 将激光增益介质 50产生大量的热量通过散热装 置水冷的方式进行冷却。
请再次参阅图 12和图 13 , 本实施例的径向偏振薄片激光器 100还包括 散热装置 54、 第二密封盖 56及冷却装置 58。
散热装置 54的材料为紫铜。 散热装置 54的一侧开设有容纳激光增益介 质 50和散热介质 55的收容腔 542 , 另一侧设计有用于增大散热面积的条状 结构 544。 散热装置 54的内部还设有冷却液循环系统 546。
第二密封盖 56大致为圆环形， 其内部设有冷却液循环系统 562。 第二密 封盖 56通过螺钉固定设置在散热装置 54的一侧。
冷却装置 58大致为空心圆筒， 其表面设有多条的散热鳍片 582。 冷却装 置 58与第二密封盖 56相贴合。 冷却装置 58的材料也为紫铜。 冷却装置 58 和第二密封盖 56上共同开始有一个指向激光增益介质 50的锥形孔 584, 以 方便聚焦透镜 30更好地将泵浦能量聚焦于激光增益介质 50上。
当激光增益介质 50受大功率的 940nm泵浦源泵浦时， 激光增益介质 50 吸收了大量的泵浦能量， 会产生大量的热， 这些热量通过散热装置 54、 散热 介质 55、 冷却液循环系统 546和冷却液循环系统 562进行循环水冷却， 及时 带走大量的热， 保护激光增益介质 50免遭因热应力炸裂及其镀膜免遭脱落。
本实施例采用大功率泵浦源泵浦激光增益介质 50, 高能量的来回振荡的 光子经过布鲁斯特双轴锥体 60时也会产生大量的热， 会产生热透镜效应， 使 得激光输出模式变差， 因此， 需要对布鲁斯特双轴锥体 60进行散热。
请参阅图 18和图 19 , 本实施例的径向偏振薄片激光器 100还包括输出 镜筒 76和第三密封盖 78。
输出镜筒 76大致为空心圆筒， 其表面设有一圈圈的散热鳍片 762。 输出 镜筒 76的一端与第三密封盖 78相配合形成输出镜腔 73。 布鲁斯特双轴锥体 60通过一个锥体压环 74被固定在输出镜腔 73的一端。 输出镜筒 76的另一 端通过一个锥形的第二泵浦头 49 (见图 11 )与第一密封盖 46固定相连。 输出透镜 70通过透镜压环 72固定在输出镜腔 73的另一端。第三密封盖 78上还设有冷却液循环系统 782。
可以理解， 本文提到的各种角度， 包括入射角 θ ;=32.4268。 、 布鲁斯特 角 Θ Β=61.2134。 ， 都可以有 ± 2分的角度公差。 细， 但并不能因此而理解为对本发明专利范围的限制。 应当指出的是， 对于 本领域的普通技术人员来说， 在不脱离本发明构思的前提下， 还可以做出若 干变形和改进， 这些都属于本发明的保护范围。 因此， 本发明专利的保护范 围应以所附权利要求为准。

Claims

权利要求书
1. 一种径向偏振薄片激光器， 其特征在于， 包括沿激光光路方向上依次排列 的泵浦源、 准直透镜、 聚焦透镜、 激光增益介质、 散热介质、 布鲁斯特双轴 锥体及输出透镜， 其中， 所述布鲁斯特双轴锥体包括两个相对的锥体和连接 所述两个锥体的柱体， 所述锥体的锥面与底面形成的夹角为布鲁斯特角， 所 述激光增益介质与所述散热介质相键合， 所述激光增益介质与所述输出透镜 之间形成激光谐振子腔， 所述泵浦源发出的泵浦激光经过所述准直透镜和聚 焦透镜后， 聚焦于所述激光增益介质， 产生的光子在所述激光谐振子腔内振 荡， 并最终从所述输出透镜输出径向偏振激光束。
2. 如权利要求 1所述的径向偏振薄片激光器， 其特征在于， 所述激光增益介 质为掺杂浓度为 5.0at%~15at°/c^ Yb:YAG圆片或掺杂浓度为 1.0at%~5.0at%的 Nd:YAG圆片， 所述 Yb:YAG圆片或 Nd:YAG圆片的厚度为 0.2~0.5mm。
3. 如权利要求 2所述的径向偏振薄片激光器， 其特征在于， 所述散热介质的 材料为 YAG晶体， 所述散热介质的厚度为所述激光增益介质的两倍。
4. 如权利要求 2所述的径向偏振薄片激光器， 其特征在于， 所述布鲁斯特双 轴锥体的材料为 YAG晶体， 所述布鲁斯特角为 61.2134。 ± 2，。
5. 如权利要求 2所述的径向偏振薄片激光器， 其特征在于， 所述布鲁斯特双 轴锥体的材料为石英， 所述布鲁斯特角为 55.4。 ± 2，。
6. 如权利要求 2所述的径向偏振薄片激光器， 其特征在于， 还包括凹面反射 镜组， 所述凹面反射镜组设置在所述激光增益介质与所述布鲁斯特双轴锥体 之间， 未被所述激光增益介质吸收的泵浦激光经所述凹面反射镜组反射后， 重新进入所述激光增益介质。
7. 如权利要求 6所述的径向偏振薄片激光器， 其特征在于， 所述凹面反射镜 组包括七片内反射镜和八片外反射镜， 所述七片内反射镜与所述聚焦透镜排 列成以所述布鲁斯特双轴锥体的轴线为对称轴的内圆环， 所述八片外反射镜 排列成一个环绕所述内圆环的外圆环。
8. 如权利要求 2所述的径向偏振薄片激光器， 其特征在于， 所述激光增益介 质远离所述布鲁斯特双轴锥体的一面设有对入射光高透、 对出射光高反的第 一双色光学膜， 所述激光增益介质靠近所述布鲁斯特双轴锥体的一面设有对 出射光高透、 对入射光高透的第二双色光学膜。
9. 如权利要求 2所述的径向偏振薄片激光器， 其特征在于， 所述散热介质的 两个底面均设有出射光高透膜。
10. 如权利要求 2 所述的径向偏振薄片激光器， 其特征在于， 所述布鲁斯特 双轴锥体的两个锥面分别设有出射光高透膜。
11. 如权利要求 6所述的径向偏振薄片激光器， 其特征在于， 还包括透镜座、 第一泵浦头及第一密封盖， 所述第一密封盖和所述第一泵浦头配合形成一个 收容所述透镜座的泵浦腔， 所述 W面反射镜组固定在所述透镜座上， 所述第 一密封盖内设有冷却液循环系统。
12. 如权利要求 2 所述的径向偏振薄片激光器， 其特征在于， 还包括散热装 置、 第二密封盖及冷却装置， 所述散热装置的一侧开设有容纳所述激光增益 介质和所述散热介质的收容腔， 所述第二密封盖固定设置在所述散热装置的 该侧， 所述冷却装置与所述第二密封盖相贴合， 所述散热装置和所述第二密 封盖上均设有冷却液循环系统。
13. 如权利要求 12所述的径向偏振薄片激光器， 其特征在于， 所述冷却装置 和所述第二密封盖上共同开设有指向所述激光增益介质的锥形孔。
14. 如权利要求 2 所述的径向偏振薄片激光器， 其特征在于， 还包括输出镜 筒和第三密封盖， 所述输出镜筒的一端与所述第三密封盖相配合形成输出镜 腔， 所述布鲁斯特双轴锥体被固定在所述输出镜腔的一端， 所述输出透镜固 定在所述输出镜腔的另一端， 所述第三密封盖上还设有冷却液循环系统。
15. 如权利要求 1 所述的径向偏振薄片激光器， 其特征在于， 所述泵浦源发 出的泵浦激光的波长为 940nm。
16. 如权利要求 1 所述的径向偏振薄片激光器， 其特征在于， 所述径向偏振 激光束的波长为 1030nm。
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CN109494551B (zh) * 2017-09-13 2024-03-01 中国科学院大连化学物理研究所 一种碟片激光器
CN114284849A (zh) * 2021-12-30 2022-04-05 云南大学 基于变焦空心光泵浦可调涡旋位相正交圆筒柱矢量激光器
CN114284849B (zh) * 2021-12-30 2024-01-09 云南大学 基于变焦空心光泵浦可调涡旋位相正交圆筒柱矢量激光器

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CN105324890B (zh) 2018-02-27

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