WO2020098413A1 - 泵浦模块及具有其的固体激光器 - Google Patents

泵浦模块及具有其的固体激光器 Download PDF

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Publication number
WO2020098413A1
WO2020098413A1 PCT/CN2019/109560 CN2019109560W WO2020098413A1 WO 2020098413 A1 WO2020098413 A1 WO 2020098413A1 CN 2019109560 W CN2019109560 W CN 2019109560W WO 2020098413 A1 WO2020098413 A1 WO 2020098413A1
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Prior art keywords
laser
pump
pump source
source
light
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PCT/CN2019/109560
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English (en)
French (fr)
Inventor
石钟恩
樊英民
蔡磊
李勇
刘兴胜
Original Assignee
西安炬光科技股份有限公司
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Priority claimed from CN201811354333.9A external-priority patent/CN109256667A/zh
Priority claimed from CN201821876635.8U external-priority patent/CN209029672U/zh
Application filed by 西安炬光科技股份有限公司 filed Critical 西安炬光科技股份有限公司
Publication of WO2020098413A1 publication Critical patent/WO2020098413A1/zh

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
    • 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

Definitions

  • the present invention relates to the technical field of pumps and solid-state lasers, and in particular, to a pump module and a solid-state laser having the same.
  • the light beam of the laser bar is longer in the slow axis direction, resulting in a greater asymmetry in the light output.
  • the single laser bar The failure of some light-emitting points of the bar will cause unevenness of the pump beam, resulting in unevenness of the solid-state laser output.
  • a single laser bar often requires a large drive current, not only high power requirements, but also a high thermal load for solid-state laser systems.
  • the main purpose of the present invention is to provide a pump module and a solid-state laser with the same, so as to solve the problems in the prior art that the laser has a large volume, a complicated structure and a low spot quality.
  • a pump module including: a pump source, which is provided in two and arranged side by side, for providing a first laser and a second laser; a fast axis collimating element , Set on the light exit side of the pump source, used for fast axis collimation of the first laser and the second laser; polarization beam combining element, placed on the light exit side of the fast axis collimation element, used to collimate the fast axis
  • the polarization directions of the first laser and the second laser are perpendicular to each other and are combined to obtain the third laser;
  • the slow axis collimating element is provided on the light exit side of the polarization combining element, and is used for slow axis compression and Gather to get a source of inspiration.
  • the polarization beam combining element includes: a half-wave plate, which is disposed on the light exit side of the fast axis collimating element, and is used to rotate the polarization direction of the first laser beam after the fast axis collimating by 90 °; the polarization beam combining mirror group, It is arranged on the light exit side of the half-wave plate and is used to combine the first laser beam after the rotation with the second laser beam after the fast axis collimation to obtain the third laser beam.
  • the two pump sources are a first pump source providing the first laser light and a second pump source providing the second laser light
  • the polarization beam combining mirror group includes: a first lens part located at the first pump source The light exit side of the second pump source is located opposite to the first pump source; the second lens part is located on the light exit side of the second pump source and is located opposite the second pump source, and the first lens part is used to reflect all the first laser light to At the position of the second lens portion, the second lens portion is used to totally reflect the first laser light and transmit all the second laser light.
  • the arrangement direction of the first pump source and the second pump source is the first direction, and in the first direction, the vertical distance between two opposite end surfaces of the first pump source is L 1 , the first lens
  • the vertical distance between the two opposite end portions is H 1
  • the vertical distance between the two opposite end surfaces of the second pump source is L 2
  • the vertical distance between the two opposite end portions of the second lens portion Is H 2 , L 1 ⁇ H 1 , L 2 ⁇ H 2
  • the midpoint of L 1 is A 1
  • the midpoint of H 1 is B 1
  • the midpoint of L 2 is A 2
  • the midpoint of H 2 is B 2.
  • the line connecting A 1 and B 1 is perpendicular to the first direction.
  • the pump sources are arranged in series.
  • the pump source is a laser bar.
  • fast axis collimating element and the slow axis collimating element are independently selected from any one of cylindrical mirrors, spherical mirrors, and aspheric mirrors.
  • a pump module including: a pump source with two pump sources arranged side by side for providing a first laser and a second laser; a beam combining element provided at the pump The light exit side of the Pu source is used to combine the first laser with the second laser to obtain the third laser as the excitation source.
  • the beam combining element is specifically a polarization beam combining element, which includes: a half-wave plate, which is arranged on the light exit side of the first laser and is used to rotate the polarization direction of the first laser after fast axis collimation by 90 °;
  • the beam mirror group is disposed on the light exit side of the half-wave plate, and is used to combine the rotated first laser light with the second laser light to obtain a third laser light.
  • the pump module further includes a fast axis collimating element and a slow axis collimating element;
  • the fast axis collimating element is disposed on the light exit side of the pump source, and is used to fast axis collimate the first laser and the second laser;
  • the slow-axis collimating element is arranged on the light exit side of the beam-combining element for slow axis compression and convergence of the third laser to obtain an excitation source; preferably, there are two fast-axis collimating elements and the light exit side of the pump source They are arranged in one-to-one correspondence; preferably, the fast axis collimating element and the slow axis collimating element are independently selected from any one of cylindrical mirrors, spherical mirrors and aspheric mirrors.
  • the pump sources are arranged in series.
  • the pump source is a semiconductor laser bar, preferably the pump source is two half semiconductor laser bars arranged side by side, and each half semiconductor laser bar arranged side by side is the same semiconductor laser bar Half.
  • the pump module further includes a conductive thermal conductive substrate, and two semiconductor laser bars are arranged side by side and bonded on the conductive thermal conductive substrate.
  • a solid-state laser including: the above-mentioned pump module, the pump module is used to generate an excitation source for implementing end-face pumping; and the crystal module is provided in the pump module for slow axis collimation The light exit side of the element is used to receive the excitation source and generate laser light.
  • the crystal module includes a gain medium crystal, a saturated absorption crystal, and a resonant cavity, the resonant cavity is provided on the light exit side of the slow axis collimating element, and the gain medium crystal and the saturated absorption crystal are provided in the resonant cavity; or, the crystal module includes a gain medium
  • the crystal and the saturation absorption crystal, the gain medium crystal and the saturation absorption crystal form a composite crystal, the composite crystal is arranged on the light emitting side of the slow axis collimating element, and in the light emitting direction of the slow axis collimating element, the two opposite end faces of the composite crystal are formed Resonant cavity.
  • a pump module in which two pump sources are arranged side by side and polarized and combined to obtain a single-spot pump light source; under the condition of dual pump sources, the polarized beam combining element can The overlapping of the output beams of the dual pump sources can improve the beam quality of the pump beam in the slow axis direction.
  • the dual pump sources form mutual backup and high-performance margins, avoiding the random emission point of a single pump source.
  • the pump source caused by the failure is abnormal or fails, which can meet the requirements of high reliability.
  • the present invention can compensate for the loss of light flux caused by the polarization combining caused by the slow axis divergence angle by improving the structure size of the PBC and adopting the special arrangement design of the pump source and the PBC, so that the light beam in the prior art can be omitted Conversion module (BTS); since BTS is not used, a pump source with more light-emitting points can be used to achieve high peak power application requirements.
  • BTS omitted Conversion module
  • the above-mentioned pump module of the present invention adopts the improved polarization beam combining technology, which solves the shortcomings that the traditional polarization beam combining scheme can only use bars with fewer light-emitting points, and the need to use BTS leads to the complexity of the optical system, resulting in improvements
  • the latter polarization beam combining scheme is compact in volume and low in luminous flux loss, and can be applied to small passive Q-switched end-pumped solid-state lasers that have strict requirements on volume and efficiency.
  • FIG. 1 shows a schematic diagram of a connection relationship of a solid-state laser provided in an embodiment of the present application
  • FIG. 2 shows a schematic diagram of the positional relationship and optical path between a single pump source and a polarization beam combining mirror group in a solid-state laser provided in the prior art
  • FIG. 3 shows a schematic diagram of the positional relationship and optical path between the single pump source and the polarization beam combining mirror group in the solid-state laser provided by the embodiment of the present application.
  • FIG. 1 includes: a pump source 1, two pump sources 1 are arranged side by side to provide the first laser and the first laser Two lasers; the fast axis collimating element 2 is provided on the light emitting side of the pump source 1 for fast axis collimation of the first laser and the second laser; the polarization beam combining element is provided on the fast axis collimating element 2
  • the light exit side is used to make the polarization directions of the first laser beam and the second laser beam after the fast axis collimation perpendicular to each other and combine them to obtain a third laser beam;
  • the slow axis collimating element 5 is provided on the light exit side of the polarization beam combining element , For slow axis compression and convergence of the third laser to obtain an excitation source.
  • the existing polarization beam combining technology is often used in fiber-coupled semiconductor laser modules. It is necessary to use a beam conversion module (BTS) to rotate the slow axis direction of the beam by 90 ° to reduce the beam parameter product (BPP) in the slow axis direction. Collimate in the direction of the slow axis before polarizing and combining.
  • BTS beam conversion module
  • BPP beam parameter product
  • the slow axis collimating lens SAC
  • PBC polarization beam combining mirror group
  • Optical loss and beam combining conversion efficiency this technical solution requires the use of a BTS system, and can only use laser bars with a small number of light-emitting points (such as 1cm bar with 19 light-emitting points), and due to the large number of optical components (generally It is composed of FAC / BTS / SAC / PBC, where FAC is a fast axis collimating lens), which requires a large space, so it is generally used in fiber coupling modules; it is difficult to require strict volume requirements and high reliability. Used in small passive Q-switched solid-state laser modules.
  • two pump sources are arranged side by side and then polarized and combined to obtain a single-spot pump light source; under the condition of dual pump sources, the polarized beam combining element can realize dual pumps
  • the overlap of the output beams of the pump source can improve the quality of the pump beam in the slow axis direction on the one hand, and the dual pump sources form a mutual backup and high performance margin on the other hand, avoiding the pump caused by the random failure of the single pump source luminous point Puyuan is abnormal or failure, which can meet the requirements of high reliability.
  • the present invention can compensate for the luminous flux of polarization beam combining due to the slow axis divergence angle by improving the structure size of the polarization beam combining mirror group (PBC) in the polarization beam combining element and adopting the special arrangement design of the pump source and PBC Loss, so that the beam conversion module (BTS) in the prior art can be omitted; because BTS is not used, a pump source with more light-emitting points can be used to achieve high peak power application requirements.
  • PBC polarization beam combining mirror group
  • BTS beam conversion module
  • the polarization beam combining element of the present invention includes a half-wave plate 3 and a polarization beam-combining lens group 4, and the half-wave plate 3 is disposed at the light exit of the fast axis collimating element 2 Side, used to rotate the polarization direction of the first laser beam after collimation of the fast axis by 90 °; the polarizing beam combiner group 4 is arranged on the light exit side of the half-wave plate 3, and is used to rotate the rotated first laser beam and the fast axis The collimated second laser beam is combined to obtain a third laser beam.
  • the above two pump sources are a first pump source 11 that provides a first laser light and a second pump source 12 that provides a second laser light.
  • the polarization beam combiner group 4 includes a first lens portion 41 and a Two lens parts 42, the first lens part 41 is located on the light exit side of the first pump source 11 and is arranged opposite to the first pump source 11, and is used to reflect all the first laser light to the position of the second lens part 42;
  • the two lens portion 42 is located on the light exit side of the second pump source 12 and is disposed opposite to the second pump source 12, and is used to totally reflect the first laser light and transmit all the second laser light, as shown in FIG. 3.
  • the first lens portion 41 and the second lens portion 42 included in the polarizing beam combiner group 4 are the key technical functional parts of the present invention.
  • the structure and optical performance of the other parts of the polarizing beam combiner group 4 can be adapted with reference to the existing structure
  • the sexual design, as long as the technical solution and technical objective of the present invention can be achieved, can meet the corresponding reflection or transmission or other related conditions.
  • the arrangement direction of the first pump source 11 and the second pump source 12 is the first direction
  • the special arrangement design of the two pump sources and the PBC may be as follows: As shown, in the above-mentioned first direction, the vertical distance between two opposite end surfaces of the first pump source 11 is L 1 , and the vertical distance between two opposite end portions of the first lens portion 41 is H 1 , The vertical distance between two opposite end surfaces of the second pump source 12 is L 2 , and the vertical distance between two opposite end portions of the second lens portion 42 is H 2 , L 1 ⁇ H 1 , L 2 ⁇ H 2 ;
  • the midpoint of L 1 is A 1
  • the midpoint of H 1 is B 1
  • the midpoint of L 2 is A 2
  • the midpoint of H 2 is B 2
  • the line between A 1 and B 1 is perpendicular to the first direction.
  • the remaining margins at both ends of the PBC are (H 1 -L 1 ) / 2, and the symmetrical arrangement and margin design of the above two pump sources and the PBC make the beams of the two pump sources Although the optical path is different, the divergence angle will not change, and the light paths exiting from the PBC can coincide with each other, so that the output light spot is not misaligned.
  • L 1 and L 2 are not clearly and strictly limited.
  • L 1 ⁇ L 2 and H 1 ⁇ H 2 are also allowed.
  • a single pump source for example, a fullbar
  • the single pump source shown does not correspond to the size, so that the outgoing light beam is misaligned. For details, see the arrow of the outgoing light shown in FIG. 2.
  • FIG. 2 In the case of adopting dual pump sources in the present invention, as shown in FIG.
  • the polarization beam combiner group 4 by designing the structural dimensions of the polarization beam combiner group 4 so that both ends have a margin compared to the pump source 1, specifically: polarization
  • the part of the beam combining mirror group corresponding to the dual pump source has a margin above and below, and the double pump source is respectively aligned with the center of the corresponding part of the polarizing beam combining mirror group, and the full angle of the divergence angle of the slow axis of the beam Generally, it is about 10 °, with a margin design so that all beams can be combined into the PBC without using the beam conversion module (BTS), and the light spot output by the PBC can be free of misalignment.
  • BTS beam conversion module
  • the pump source 1 may be a laser bar, and the laser bar may be a semiconductor laser bar.
  • the pump source 1 is two half semiconductor laser bars arranged side by side, and each half semiconductor laser bar arranged side by side is half of the same semiconductor laser bar; and, Preferably, the pump source 1 is encapsulated by arranging and bonding two semiconductor laser bars side by side on the conductive and thermally conductive substrate.
  • two pump sources 1 are arranged in series. That is, the negative electrode of one pump source 1 is connected to the positive electrode of the other pump source 1, and the positive electrodes and negative electrodes of the two pump sources 1 that are not connected are respectively connected to the power source.
  • the two series-connected pump sources 1 only need a small driving current to achieve a large light output power, which greatly reduces the requirements on the power supply and also reduces the thermal load in the system.
  • BTS beam conversion module
  • BPP beam parameter product
  • the BTS may not be used, thereby overcoming the shortcoming that the traditional polarization beam combining scheme can only use fewer light-emitting points, and the light-emitting points of the pump source 1 are not affected by the structure itself
  • the limitation makes the polarization beam combining technology applicable to some bar lasers that require high peak power and quasi-continuous (QCW) operation with more light-emitting points.
  • the fast axis collimating element 2 may be one located on the light emitting sides of the two pump sources 1, or may be two and are provided in one-to-one correspondence with the light emitting sides of the pump sources 1 ,As shown in Figure 1.
  • the fast axis collimating element 2 and the slow axis collimating element 5 are independently selected from any one of cylindrical mirrors, spherical mirrors, and aspheric mirrors.
  • the above-mentioned pump module of the present invention can be specifically used to generate an excitation source for implementing end-face pumping.
  • a pump module is provided. As shown in FIG. 1, it includes a pump source 1 and a beam combining element.
  • the pump source 1 is two and arranged side by side for providing the first laser and Two lasers; a beam combining element is provided on the light emitting side of the pump source 1 for combining the first laser with the second laser to obtain a third laser as an excitation source.
  • a single bar light output is directly coupled to a crystal for pumping, which is likely to cause uneven light output of the laser with the pump source.
  • two pump sources are arranged side by side Combined beams can not only improve the uniformity of the pump light source, but also reduce the thermal load; and, the dual pump sources form mutual backup and high-performance margins, avoiding the pump source caused by the random failure of the single pump source light point. Abnormal or failure, which can meet the requirements of high reliability.
  • the aforementioned beam combining element may be a polarizing beam combining element.
  • the polarizing beam combining element includes a half-wave plate 3 and a polarizing beam combining mirror group 4, as shown in FIG. 1, the half-wave plate 3 is provided in The exit position of the first laser is used to rotate the polarization direction of the first laser by 90 °; the polarization beam combiner group 4 is provided on the exit side of the half-wave plate 3 and is used to rotate the rotated first laser and the second laser The third laser is obtained by performing beam combining.
  • the pump module of the present invention further includes a fast axis collimating element 2 and a slow axis collimating element 5; as shown in FIG. 1, the fast axis collimating element 2 is provided on the light exit side of the pump source 1, It is used to fast-axis collimate the first laser and the second laser; the slow-axis collimating element 5 is provided on the light exit side of the combining element, and is used to slow-axis compress and converge the third laser to obtain an excitation source. More preferably, there are two fast axis collimating elements 2 and they are provided in one-to-one correspondence with the light exit side of the pump source 1, as shown in FIG. 1.
  • the fast axis collimating element 2 and the slow axis collimating element 5 may be independently selected from any one of cylindrical mirrors, spherical mirrors, and aspheric mirrors.
  • the half-wave plate 3 in the polarization beam combining element is disposed on the light exit side of the fast axis collimating element 2 , Used to rotate the polarization direction of the first laser beam after the fast axis collimation by 90 °; the polarization beam combining mirror group 4 in the polarization beam combining element is arranged on the light exit side of the half-wave plate 3, and is used to rotate the rotated first A laser is combined with the second laser after the fast axis collimation to obtain a third laser.
  • the above two pump sources 1 are respectively a first pump source 11 providing a first laser light and a second pump source 12 providing a second laser light.
  • the polarization beam combining mirror group 4 includes a first lens portion 41 and The second lens portion 42, the first lens portion 41 is located on the light exit side of the first pump source 11 and is opposite to the first pump source 11; the second lens portion 42 is located on the light exit side of the second pump source 12 and is The two pump sources 12 are oppositely arranged.
  • the first lens portion 41 is used to reflect the first laser light to the position of the second lens portion 42.
  • the second lens portion 42 is used to reflect the first laser light and transmit the second laser light. As shown in Figure 3.
  • the first lens portion 41 and the second lens portion 42 included in the polarizing beam combiner group 4 are the key technical functional parts of the present invention.
  • the structure and optical performance of the other parts of the polarizing beam combiner group 4 can be adapted with reference to the existing structure
  • the sexual design, as long as the technical solution and technical objective of the present invention can be achieved, can meet the corresponding reflection or transmission or other related conditions.
  • the arrangement direction of the first pump source 11 and the second pump source 12 is the first direction
  • the special arrangement design of the two pump sources and the PBC may be as follows: As shown, in the first direction, the vertical distance between the opposite end surfaces of the first pump source 11 is L 1 , and the vertical distance between the opposite end portions of the first lens portion 41 is H 1 , The vertical distance between two opposite end surfaces of the second pump source 12 is L 2 , and the vertical distance between two opposite end portions of the second lens portion 42 is H 2 , L 1 ⁇ H 1 , L 2 ⁇ H 2 ;
  • the midpoint of L 1 is A 1
  • the midpoint of H 1 is B 1
  • the midpoint of L 2 is A 2
  • the midpoint of H 2 is B 2
  • the line between A 1 and B 1 is perpendicular to the first direction .
  • the remaining margins at both ends of the PBC are (H 1 -L 1 ) / 2, and the symmetrical arrangement and margin design of the above two pump sources and the PBC make the beams of the two pump sources Although the optical path is different, the divergence angle will not change, and the light paths exiting from the PBC can coincide with each other, so that the output light spot is not misaligned.
  • L 1 and L 2 are not clearly and strictly limited.
  • L 1 ⁇ L 2 and H 1 ⁇ H 2 are also allowed.
  • the pump source 1 may be a semiconductor laser bar, preferably two half semiconductor laser bars arranged side by side, and each half arranged side by side
  • the semiconductor laser bar is half of the same semiconductor laser bar; and, preferably, by arranging and bonding two semiconductor laser bars side by side on the conductive and thermally conductive substrate, the pump source 1 is packaged.
  • two pump sources 1 are arranged in series. That is, the negative electrode of one pump source 1 is connected to the positive electrode of the other pump source 1, and the positive electrodes and negative electrodes of the two pump sources 1 that are not connected are respectively connected to the power source.
  • the two series-connected pump sources 1 only need a small driving current to achieve a large light output power, which greatly reduces the requirements on the power supply and also reduces the thermal load in the system.
  • a solid-state laser as shown in FIG. 1, comprising the above-mentioned pump module and a crystal module, the pump module is used to generate an excitation source for implementing end-face pumping, and the crystal module is provided in The light emitting side of the slow axis collimating element 5 in the pump module is used to receive the excitation source and generate laser light.
  • a slow-axis collimating element 5 is used to converge the direction of the slow axis, so that the beams are converged into the crystal module to realize high-efficiency pumping .
  • the solid-state laser of the present invention may be a passive Q-switched end-face pumped solid-state laser. Because existing passive Q-switched end-face pumped solid-state laser solutions generally use fiber coupling modules as the pump source, or use a single bar to directly couple the light to the crystal for pumping, it is easy to cause problems of bulkiness and uneven light output.
  • the above-mentioned pump module of the present invention adopts the improved polarization beam combining technology, which solves the shortcomings that the traditional polarization beam combining scheme can only use bars with fewer light emitting points, and the need to use BTS leads to the complexity of the optical system, resulting in improved
  • the polarization beam combining scheme is compact in size and low in luminous flux loss, and can be applied to small passive Q-switched solid-state lasers with strict requirements on volume and efficiency.
  • PBC can be used to directly combine beams that have not been collimated in the slow axis direction. , Make up for the loss of polarized light flux caused by the slow axis divergence angle; because BTS is not used, you can use chips with more light-emitting points to achieve high peak power application requirements.
  • two bars are arranged side by side (further arranged in series) for polarization combining to achieve a single-spot pump light source; under the condition of dual pump sources, PBC can achieve the dual pump source beam Overlap, on the one hand, can improve the quality of the slow beam direction of the pump beam, on the other hand, the dual pump sources form mutual backup and high-performance margins, to avoid the pump abnormality or failure caused by the random failure of a single bar light point, and solved
  • the problem of poor beam symmetry and poor reliability of a passively Q-switched solid-state laser with a single bar directly coupled meets the requirements for high reliability.
  • the excitation source generated by the pump module for end-face pumping can be incident on the left and right end faces of the crystal module near the excitation source to realize the end-pumped solid-state laser, specifically:
  • the above-mentioned crystal module includes a gain medium crystal 7, a saturation absorption crystal 8 and a resonant cavity.
  • the resonance cavity is provided on the light emitting side of the slow axis collimating element 5, and the gain medium crystal 7 and the saturation absorption crystal 8 are provided In the resonant cavity.
  • a person skilled in the art can reasonably select the types of the above-mentioned gain medium crystal 7 and saturation absorption crystal 8 according to the prior art, which will not be repeated here.
  • the above-mentioned crystal module includes a gain medium crystal 7 and a saturation absorption crystal 8, the gain medium crystal 7 and the saturation absorption crystal 8 form a composite crystal, and the composite crystal is disposed on the light exit side of the slow axis collimating element 5 And, in the light exit direction of the slow axis collimating element 5, the two opposite end surfaces of the composite crystal form a resonant cavity.
  • the resonant cavity is formed by the structure of the crystal itself, and no additional resonant cavity mirror is needed, so that the structure of the laser is simpler and more compact.
  • the gain medium crystal 7 is any one of Nd: YAG, Er: glass and Er: Yb: YAG; the saturation absorption crystal 8 is Cr: YAG or cobalt doped spinel (Cobalt Spinel).
  • the cobalt spinel may be Co: MgAl2O4.
  • the above-mentioned saturation absorption crystal is Cr: YAG, and is used together with the gain medium crystals Nd: YAG, Yb: YAG; or, the above-mentioned saturation absorption crystal is Co: MgAl2O4, and together with the gain medium Er, Yb: glass ( Er, Yb co-doped together).
  • the resonant cavity of the present invention may be composed of two independent cavity mirrors (high-reflection lens 6 and partial reflection lens 9).
  • the high-reflection lens 6 and partial reflection lens 9 may also be composed of two crystals
  • the two end faces are formed as long as the two end faces satisfy the conditions of reflectivity.
  • This embodiment uses a solid-state laser as shown in Figure 1.
  • the solution mainly includes:
  • Two semiconductor laser bars as dual pump sources 1 fast axis collimating element 2 are two fast axis collimating lenses, half-wave plate 3, polarization beam combiner group 4, slow axis collimating element 5 is cylindrical
  • the two bars are placed side by side, and the fast axis collimation of the beam is performed by the fast axis collimating lens; the half-wave plate is placed in front of one of the bars, and the polarization direction of the beam of the bar is rotated by 90 °; the polarization The beam rotated by 90 degrees and the other beam pass through the polarizing beam combining lens group, and are combined into the same beam; the combined beam passes through the cylindrical mirror for compression and convergence in the slow axis direction, and then enters the end face of the gain medium crystal for pumping Pu effect.
  • the two bars are placed side by side, and the two bars are connected in series in electrical connection. Compared with a longer single bar or two parallel bars, two bar bars connected in series require a smaller drive current to achieve a higher light output power, and on the other hand reduce the thermal load in the system .
  • the above-mentioned polarization beam combiner group can realize the overlapping of two bar beams as dual pump sources, on the one hand, it can improve the quality of the slow beam direction of the pump beam, on the other hand, the dual pump source is formed Mutual backup and high-performance margin to avoid the pump abnormality or failure caused by the random failure of a single bar light-emitting point, which can meet the requirements of high reliability.
  • the two pump sources are arranged side by side and then polarized and combined to obtain a single-spot pump light source; under the condition of dual pump sources, the polarized beam combining element can realize the output of the dual pump sources.
  • the overlapping of the beams can improve the quality of the pump beam in the slow axis direction on the one hand, on the other hand, the dual pump sources form mutual backup and high-performance margins, avoiding the pump source abnormality caused by the random failure of the single pump source luminous point. Or failure, so as to meet the requirements of high reliability;
  • the polarization beam combining mirror group (PBC) in the slow axis collimating element By improving the structure size of the polarization beam combining mirror group (PBC) in the slow axis collimating element and using the special arrangement design of the pump source and PBC, the light flux loss of the polarization beam combining due to the slow axis divergence angle is compensated, thus Can eliminate the beam conversion module (BTS) in the prior art; because BTS is not used, it is possible to use a pump source with more light-emitting points to achieve high peak power application requirements;
  • BTS beam conversion module
  • the existing passive Q-switched solid-state laser solutions generally use fiber coupling modules as pump sources, or use a single bar to directly couple the light to the crystal for pumping, it is easy to cause problems of bulkiness and uneven light output.
  • the above-mentioned pump module of the present invention adopts the improved polarization beam combining technology, which solves the shortcomings that the traditional polarization beam combining scheme can only use bars with fewer light emitting points, and the need to use BTS leads to the complexity of the optical system, resulting in improved
  • the polarization beam combining scheme is compact in size and low in luminous flux loss, and can be applied to small passive Q-switched end-face pumped solid-state lasers that have strict requirements on volume and efficiency.

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Abstract

一种泵浦模块及具有其的固体激光器，泵浦模块包括：泵浦源，泵浦源为两个且并排设置，用于提供第一激光和第二激光；快轴准直元件，设置于泵浦源的出光侧，用于对第一激光和第二激光进行快轴准直；偏振合束元件，设置于快轴准直元件的出光侧，用于使快轴准直后的第一激光与第二激光的偏振方向相互垂直并进行合束以得到第三激光；慢轴准直元件，设置于偏振合束元件的出光侧，用于对第三激光进行慢轴压缩和汇聚以得到激励源。泵浦模块一方面提高泵浦光束的慢轴方向光束质量，另一方面双泵浦源形成相互备份和高性能余量，避免了单个泵浦源发光点随机失效造成的泵浦源异常或失效，从而能够满足高可靠性使用要求。

Description

泵浦模块及具有其的固体激光器 技术领域
本发明涉及泵浦及固体激光器技术领域，具体而言，涉及一种泵浦模块及具有其的固体激光器。
背景技术
现有的被动调Q固体激光器方案一般采用光纤耦合模块作为泵浦源，或者采用单个激光巴条出光直接耦合至晶体进行泵浦。
采用光纤耦合模块作为泵浦源的被动调Q固体激光器，由于光纤耦合模块和晶体模块(包括光学、晶体、腔镜等)分开，因此一般需要这两个模块组合在一起才能实现工作，整体结构过于复杂和庞大，在一些需要集成应用、对体积要求严格的应用场合(例如车载激光雷达)很难适用。
而采用单个激光巴条出光直接耦合至激光晶体进行端面泵浦的被动固体激光器，由于激光巴条的光束在慢轴方向较长，导致出光具有较大的不对称性；此外，由于单个激光巴条的某些发光点失效，会引起泵浦光束的不均匀，从而导致固体激光输出的不均匀。
此外，在高功率的应用中，单个激光巴条往往需要较大的驱动电流，不仅对电源的要求高，而且对于固体激光器系统而言热负载较高。
发明内容
本发明的主要目的在于提供一种泵浦模块及具有其的固体激光器，以解决现有技术中的激光器体积庞大、结构复杂且光斑质量低的问题。
为了实现上述目的，根据本发明的一个方面，提供了泵浦模块，包括：泵浦源，泵浦源为两个且并排设置，用于提供第一激光和第二激光；快轴准直元件，设置于泵浦源的出光侧，用于对第一激光和第二激光进行快轴准直；偏振合束元件，设置于快轴准直元件的出光侧，用于使快轴准直后的第一激光与第二激光的偏振方向相互垂直并进行合束以得到第三激光；慢轴准直元件，设置于偏振合束元件的出光侧，用于对第三激光进行慢轴压缩和汇聚以得到激励源。
进一步地，偏振合束元件包括：半波片，设置于快轴准直元件的出光侧，用于对快轴准直后的第一激光的偏振方向进行90°旋转；偏振合束镜组，设置于半波片的出光侧，用于将旋转后的第一激光与快轴准直后的第二激光进行合束得到第三激光。
进一步地，两个泵浦源分别为提供第一激光的第一泵浦源以及提供第二激光的第二泵浦源，偏振合束镜组包括：第一透镜部，位于第一泵浦源的出光侧并与第一泵浦源相对设置； 第二透镜部，位于第二泵浦源的出光侧并与第二泵浦源相对设置，第一透镜部用于将第一激光全部反射至第二透镜部的位置处，第二透镜部用于全部反射第一激光并全部透射第二激光。
进一步地，第一泵浦源与第二泵浦源的排列方向为第一方向，在第一方向上，第一泵浦源相对的两个端面之间的垂直距离为L 1，第一透镜部相对的两个端部之间的垂直距离为H 1，第二泵浦源相对的两个端面之间的垂直距离为L 2，第二透镜部相对的两个端部之间的垂直距离为H 2，L 1＜H 1，L 2＜H 2；L 1的中点为A 1，H 1的中点为B 1，L 2的中点为A 2，H 2的中点为B 2，A 1与B 1的连线垂直于第一方向。
进一步地，泵浦源串联设置。
进一步地，泵浦源为激光巴条。
进一步地，快轴准直元件为两个且与泵浦源的出光侧一一对应地设置。
进一步地，快轴准直元件和慢轴准直元件独立地选自柱面镜、球面镜和非球面镜中的任一种。
根据本发明的另一方面，提供了一种泵浦模块，包括：泵浦源，泵浦源为两个且并排设置，用于提供第一激光和第二激光；合束元件，设置于泵浦源的出光侧，用于使第一激光与第二激光进行合束以得到作为激励源的第三激光。
进一步地，合束元件具体为偏振合束元件，包括：半波片，设置于第一激光的出光侧，用于对快轴准直后的第一激光的偏振方向进行90°旋转；偏振合束镜组，设置于半波片的出光侧，用于将旋转后的第一激光与第二激光进行合束得到第三激光。
进一步地，泵浦模块还包括快轴准直元件和慢轴准直元件；快轴准直元件设置于泵浦源的出光侧，用于对第一激光和第二激光进行快轴准直；慢轴准直元件设置于合束元件的出光侧，用于对第三激光进行慢轴压缩和汇聚以得到激励源；优选地，快轴准直元件为两个且与泵浦源的出光侧一一对应地设置；优选地，快轴准直元件和慢轴准直元件独立地选自柱面镜、球面镜和非球面镜中的任一种。
进一步地，泵浦源串联设置。
进一步地，泵浦源为半导体激光巴条，优选泵浦源为并排设置的两个二分之一半导体激光巴条，并排设置的各二分之一半导体激光巴条为同一个半导体激光巴条的一半。
进一步地，泵浦模块还包括导电导热衬底，两个半导体激光巴条并排设置并键合在导电导热衬底上。
根据本发明的另一方面，提供了一种固体激光器，包括：上述的泵浦模块，泵浦模块用于产生实现端面泵浦的激励源；晶体模块，设置于泵浦模块中慢轴准直元件的出光侧，用于接收激励源并产生激光。
进一步地，晶体模块包括增益介质晶体、饱和吸收晶体和谐振腔，谐振腔设置于慢轴准直元件的出光侧，增益介质晶体和饱和吸收晶体设置于谐振腔中；或者，晶体模块包括增益介质晶体和饱和吸收晶体，增益介质晶体与饱和吸收晶体形成复合晶体，复合晶体设置于慢轴准直元件的出光侧，且在慢轴准直元件的出光方向上，复合晶体相对的两个端面形成谐振腔。
应用本发明的技术方案，提供了一种泵浦模块，采取两个泵浦源并排设置后进行偏振合束得到单光斑的泵浦光源；在双泵浦源的条件下，偏振合束元件能够实现对双泵浦源输出光束的重叠，一方面可以提高泵浦光束的慢轴方向光束质量，另一方面双泵浦源形成相互备份和高性能余量，避免了单个泵浦源发光点随机失效造成的泵浦源异常或失效，从而能够满足高可靠性使用要求。进一步地，本发明能够通过改进PBC结构尺寸以及采用泵浦源与PBC的特殊排布设计，弥补了由于慢轴发散角引起的偏振合束的光通量损失，从而能够省去现有技术中的光束转换模块(BTS)；由于未采用BTS，因此可以使用具有较多发光点的泵浦源实现高峰值功率应用需求。并且，本发明的上述泵浦模块中采用了改进的偏振合束技术，解决了传统偏振合束方案只能使用较少发光点的巴条、需要使用BTS导致光学系统复杂庞大的缺点，使得改进后的偏振合束方案体积紧凑、光通量损失小，可应用于对体积和效率要求严格的小型被动调Q端面泵浦固体激光器中。
附图说明
构成本发明的一部分的说明书附图用来提供对本发明的进一步理解，本发明的示意性实施例及其说明用于解释本发明，并不构成对本发明的不当限定。在附图中：
图1示出了在本申请实施方式所提供的一种固体激光器的连接关系示意图；
图2示出了现有技术中所提供的一种固体激光器中单泵浦源与偏振合束镜组之间的位置关系以及光路示意图；以及
图3示出了在本申请实施方式所提供的固体激光器中单泵浦源与偏振合束镜组之间的位置关系以及光路示意图。
其中，上述附图包括以下附图标记：
1＇、泵浦源；4＇、偏振合束镜组；1、泵浦源；11、第一泵浦源；12、第二泵浦源；2、快轴准直元件；3、半波片；4、偏振合束镜组；41、第一透镜部；42、第二透镜部；5、慢轴准直元件；6、高反镜片；7、增益介质晶体；8、饱和吸收晶体；9、部分反射镜片。
具体实施方式
需要说明的是，在不冲突的情况下，本发明中的实施例及实施例中的特征可以相互组合。下面将参考附图并结合实施例来详细说明本发明。
为了使本技术领域的人员更好地理解本发明方案，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分的实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都应当属于本发明保护的范围。
需要说明的是，本发明的说明书和权利要求书及上述附图中的术语“第一”、“第二”等是用于区别类似的对象，而不必用于描述特定的顺序或先后次序。应该理解这样使用的数据在适当情况下可以互换，以便这里描述的本发明的实施例。此外，术语“包括”和“具有”以及他们的任何变形，意图在于覆盖不排他的包含，例如，包含了一系列步骤或单元的过程、方法、系统、产品或设备不必限于清楚地列出的那些步骤或单元，而是可包括没有清楚地列出的或对于这些过程、方法、产品或设备固有的其它步骤或单元。
正如背景技术中所介绍的，现有技术中的激光器体积庞大且结构复杂。本发明的发明人针对上述问题进行研究，提出了一种固体激光器，如图1所示，包括：泵浦源1，泵浦源1为两个且并排设置，用于提供第一激光和第二激光；快轴准直元件2，设置于泵浦源1的出光侧，用于对第一激光和第二激光进行快轴准直；偏振合束元件，设置于快轴准直元件2的出光侧，用于使快轴准直后的第一激光与第二激光的偏振方向相互垂直并进行合束以得到第三激光；慢轴准直元件5，设置于偏振合束元件的出光侧，用于对第三激光进行慢轴压缩和汇聚以得到激励源。
现有的偏振合束技术常应用于光纤耦合半导体激光器模块中，需要使用光束转换模块(BTS)对光束慢轴方向进行旋转90°，减小慢轴方向的光束参数积(BPP)，然后对慢轴方向进行准直，之后才进行偏振合束。
上述现有方案中由于先采用慢轴准直透镜(SAC)对光束慢轴方向进行准直，再采用偏振合束镜组(PBC)进行偏振合束，从而能够实现较少的慢轴方向的光损失和合束转换效率；然而，这种技术方案需要使用BTS系统，且只能使用发光点数较少的激光巴条(例如19个发光点的1cm巴条)，并且由于光学元件较多(一般由FAC/BTS/SAC/PBC构成，其中FAC为快轴准直透镜)，从而需要较大的空间，因此一般多应用于光纤耦合模块中；难以在对体积要求较为严格、需要高可靠性的小型被动调Q固体激光器模块中使用。
而本发明提供的上述泵浦模块中由于采取两个泵浦源并排设置后进行偏振合束得到单光斑的泵浦光源；在双泵浦源的条件下，偏振合束元件能够实现对双泵浦源输出光束的重叠，一方面可以提高泵浦光束的慢轴方向光束质量，另一方面双泵浦源形成相互备份和高性能余量，避免了单个泵浦源发光点随机失效造成的泵浦源异常或失效，从而能够满足高可靠性使用要求。进一步地，本发明能够通过改进偏振合束元件中偏振合束镜组(PBC)结构尺寸以及采用泵浦源与PBC的特殊排布设计，弥补了由于慢轴发散角引起的偏振合束的光通量损失，从而能够省去现有技术中的光束转换模块(BTS)；由于未采用BTS，因此可以使用具有较多发光点的泵浦源实现高峰值功率应用需求。
在一种优选的实施方式中，如图1所示，本发明的上述偏振合束元件包括半波片3和偏振合束镜组4，半波片3设置于快轴准直元件2的出光侧，用于对快轴准直后的第一激光的偏振方向进行90°旋转；偏振合束镜组4设置于半波片3的出光侧，用于将旋转后的第一激光与快轴准直后的第二激光进行合束得到第三激光。
上述两个泵浦源分别为提供第一激光的第一泵浦源11以及提供第二激光的第二泵浦源12，优选地，上述偏振合束镜组4包括第一透镜部41和第二透镜部42，第一透镜部41位于第一泵浦源11的出光侧并与第一泵浦源11相对设置，用于将第一激光全部反射至第二透镜部42的位置处；第二透镜部42位于第二泵浦源12的出光侧并与第二泵浦源12相对设置，用于全部反射第一激光并全部透射第二激光，如图3所示。
上述偏振合束镜组4包括的第一透镜部41和第二透镜部42为本发明的关键技术功能部分，偏振合束镜组4的其他部分的结构和光学性能可参照现有结构进行适应性设计，在保证本发明技术方案和技术目的能够实现的情况下，满足相应的反射或透射或其他相关条件即可。
在上述优选的实施方式中，以上述第一泵浦源11与上述第二泵浦源12的排列方向为第一方向，两个泵浦源与PBC的特殊排布设计可以为：如图3所示，在上述第一方向上，第一泵浦源11相对的两个端面之间的垂直距离为L 1，第一透镜部41相对的两个端部之间的垂直距离为H 1，第二泵浦源12相对的两个端面之间的垂直距离为L 2，第二透镜部42相对的两个端部之间的垂直距离为H 2，L 1＜H 1，L 2＜H 2；L 1的中点为A 1，H 1的中点为B 1，L 2的中点为A 2，H 2的中点为B 2，A 1与B 1的连线垂直于第一方向。此时，PBC两端留有的余量分别为(H 1-L 1)/2，以上两个泵浦源与PBC的对称式的排布及余量设计，使得两个泵浦源的光束虽然光程不同，但发散角不会发生变化，从PBC出射的光路能够相互重合，使得输出的光斑没有错位。
本发明实施例中，并不明确严格限制L 1与L 2的关系，为了方便设计与生产，使本发明的技术目的和技术效果更佳，可以使L 1＝L 2，H 1＝H 2；当然，在某些对技术效果要求不严格的一些应用场景中，L 1≠L 2，H 1≠H 2也是允许的。
由于现有技术中通常采用单一泵浦源(例如一个fullbar)，通常为了实现光束全部进入器件，需要偏振合束镜组4＇的尺寸与该泵浦源1＇的尺寸完全对应，而图2所示的单一泵浦源由于尺寸不对应，使得出射后的光束出现错位，具体见图2所示的出射光的箭头。而本发明在采用双泵浦源的情况下，如图3所示，通过设计偏振合束镜组4的结构尺寸使其两端相较于泵浦源1留有余量，具体为：偏振合束镜组分别与双泵浦源其一对应的部分，上下分别留有余量，并且双泵源分别与偏振合束镜组对应的部分的中心对齐设置，而光束慢轴发散角的全角一般为10°左右，留有余量的设计从而能够在不使用光束转换模块(BTS)的情况下，仍然可以使所有的光束进入PBC中进行合束，并且可以使PBC输出的光斑无错位。
在本发明的上述泵浦模块中，泵浦源1为可以采用激光巴条，上述激光巴条可以为半导体激光巴条。优选地，泵浦源1为并排设置的两个二分之一半导体激光巴条(half bar)，并排设置的各二分之一半导体激光巴条为同一个半导体激光巴条的一半；并且，优选地，通过将两个半导体激光巴条并排设置并键合在导电导热衬底上，以实现泵浦源1的封装。
优选地，两个泵浦源1之间串联设置。即一个泵浦源1的负极连接另一个泵浦源1的正极，而两个泵浦源1上未连接的正极与负极分别与电源连接。两个串联的泵浦源1仅需要较小的驱动电流就可以实现较大的出光功率，大大降低了对电源的要求，并且还会减小系统中的热负载。
并且，由于传统的光纤耦合半导体激光器模块中，需要使用BTS(光束转换模块)对光束慢轴方向进行旋转90°，减小慢轴方向的光束参数积(BPP)，然后对慢轴方向进行准直，之后才进行偏振合束，而这种技术方案需要使用BTS系统，且由于巴条的每个发光点需要与BTS中的每个单元一一对应，因此只能使用具有较少发光点的巴条/单管芯片(例如常用的有19个发光点)。而采用本发明的上述泵浦模块，由于可以不采用BTS，从而克服了传统偏振合束方案只能使用较少发光点的巴条的缺点，能够使泵浦源1的发光点不受结构本身限制，使偏振合束技术能够应用于一些需要高峰值功率、准连续(QCW)工作的具有较多发光点的巴条激光器中。
在本发明的上述泵浦模块中，快轴准直元件2可以为位于两个泵浦源1的出光侧的一个，还可以为两个并与泵浦源1的出光侧一一对应地设置，如图1所示。上述快轴准直元件2与慢轴准直元件5独立地选自柱面镜、球面镜和非球面镜中的任一种。
本发明的上述泵浦模块，具体可以用于产生实现端面泵浦的激励源。
根据本发明的另一方面，提供了一种泵浦模块，如图1所示，包括泵浦源1和合束元件，泵浦源1为两个且并排设置，用于提供第一激光和第二激光；合束元件设置于泵浦源1的出光侧，用于使第一激光与第二激光进行合束以得到作为激励源的第三激光。
由于现有技术中采用单个巴条出光直接耦合至晶体进行泵浦，易导致具有该泵浦源的激光器的出光不均匀，而本发明的上述泵浦模块中，采取两个泵浦源并排设置进行合束，不仅能够提高泵浦光源的均匀性，还能够降低热负载；并且，双泵浦源形成相互备份和高性能余量，避免了单个泵浦源发光点随机失效造成的泵浦源异常或失效，从而能够满足高可靠性使用要求。
上述合束元件可以为偏振合束元件，在一种优选的实施方式中，该偏振合束元件包括半波片3和偏振合束镜组4，如图1所示，半波片3设置于第一激光的出光处，用于对第一激光的偏振方向进行90°旋转；偏振合束镜组4设置于半波片3的出光侧，用于将旋转后的第一激光与第二激光进行合束得到第三激光。
更为优选地，本发明的上述泵浦模块还包括快轴准直元件2和慢轴准直元件5；如图1所示，快轴准直元件2设置于泵浦源1的出光侧，用于对第一激光和第二激光进行快轴准直；慢轴准直元件5设置于合束元件的出光侧，用于对第三激光进行慢轴压缩和汇聚以得到激励源。更为优选地，快轴准直元件2为两个且与泵浦源1的出光侧一一对应地设置，如图1所示。
上述快轴准直元件2和上述慢轴准直元件5可以独立地选自柱面镜、球面镜和非球面镜中的任一种。
在具有上述快轴准直元件2和上述慢轴准直元件5的泵浦模块中，如图1所示，偏振合束元件中的半波片3设置于快轴准直元件2的出光侧，用于对快轴准直后的第一激光的偏振方向进行90°旋转；偏振合束元件中的偏振合束镜组4设置于半波片3的出光侧，用于将旋转后的第一激光与快轴准直后的第二激光进行合束得到第三激光。
上述两个泵浦源1分别为提供第一激光的第一泵浦源11以及提供第二激光的第二泵浦源12，优选地，上述偏振合束镜组4包括第一透镜部41和第二透镜部42，第一透镜部41位于第一泵浦源11的出光侧并与第一泵浦源11相对设置；第二透镜部42位于第二泵浦源12的出光侧并与第二泵浦源12相对设置，第一透镜部41用于将第一激光全部反射至第二透镜部42的位置处，第二透镜部42用于全部反射第一激光并全部透射第二激光，如图3所示。
上述偏振合束镜组4包括的第一透镜部41和第二透镜部42为本发明的关键技术功能部分，偏振合束镜组4的其他部分的结构和光学性能可参照现有结构进行适应性设计，在保证本发明技术方案和技术目的能够实现的情况下，满足相应的反射或透射或其他相关条件即可。
在上述优选的实施方式中，以上述第一泵浦源11与上述第二泵浦源12的排列方向为第一方向，两个泵浦源与PBC的特殊排布设计可以为：如图3所示，在第一方向上，第一泵浦源11相对的两个端面之间的垂直距离为L 1，第一透镜部41相对的两个端部之间的垂直距离为H 1，第二泵浦源12相对的两个端面之间的垂直距离为L 2，第二透镜部42相对的两个端部之间的垂直距离为H 2，L 1＜H 1，L 2＜H 2；L 1的中点为A 1，H 1的中点为B 1，L 2的中点为A 2，H 2的中点为B 2，A 1与B 1的连线垂直于第一方向。此时，PBC两端留有的余量分别为(H 1-L 1)/2，以上两个泵浦源与PBC的对称式的排布及余量设计，使得两个泵浦源的光束虽然光程不同，但发散角不会发生变化，从PBC出射的光路能够相互重合，使得输出的光斑没有错位。
本发明实施例中，并不明确严格限制L 1与L 2的关系，为了方便设计与生产，使本发明的技术目的和技术效果更佳，可以使L 1＝L 2，H 1＝H 2；当然，在某些对技术效果要求不严格的一些应用场景中，L 1≠L 2，H 1≠H 2也是允许的。
在本发明的上述泵浦模块中，泵浦源1为可以采用半导体激光巴条，优选为并排设置的两个二分之一半导体激光巴条(half bar)，并排设置的各二分之一半导体激光巴条为同一个半导体激光巴条的一半；并且，优选地，通过将两个半导体激光巴条并排设置并键合在导电导热衬底上，以实现泵浦源1的封装。
在本发明的上述泵浦模块中，优选地，两个泵浦源1之间串联设置。即一个泵浦源1的负极连接另一个泵浦源1的正极，而两个泵浦源1上未连接的正极与负极分别与电源连接。两个串联的泵浦源1仅需要较小的驱动电流就可以实现较大的出光功率，大大降低了对电源的要求，并且还会减小系统中的热负载。
根据本发明的另一方面，还提供了一种固体激光器，如图1所示，包括上述的泵浦模块以及晶体模块，泵浦模块用于产生实现端面泵浦的激励源，晶体模块设置于泵浦模块中慢轴准直元件5的出光侧，用于接收激励源并产生激光。在上述固体激光器中，通过PBC对两个泵浦源的光束进行合束之后，再使用一个慢轴准直元件5对慢轴方向进行汇聚，使光束汇聚进入晶体模块，实现高效率的泵浦。
本发明的上述固体激光器可以为被动调Q端面泵浦固体激光器。由于现有的被动调Q端面泵浦固体激光器方案一般采用光纤耦合模块作为泵浦源，或者采用单个巴条出光直接耦合至晶体进行泵浦，从而易导致体积庞大以及出光不均匀的问题。而本发明的上述泵浦模块中采用了改进的偏振合束技术，解决了传统偏振合束方案只能使用较少发光点的巴条、需要使用BTS导致光学系统复杂庞大的缺点，使得改进后的偏振合束方案体积紧凑、光通量损失小，可应用于对体积和效率要求严格的小型被动调Q固体激光器中。
并且，在本发明的上述动调Q固体激光器中，可以采用PBC对未经过慢轴方向准直的光束直接合束，通过改进PBC的结构尺寸以及采用双泵浦源与PBC的特殊排布设计，弥补了由于慢轴发散角引起的偏振合束的光通量损失；由于未采用BTS，因此可以使用具有较多发光点的芯片实现高峰值功率应用需求。
同时，本方案中采取两个巴条并排设置(还以进一步串联设置)进行偏振合束实现了单光斑的泵浦光源；在双泵源的条件下，PBC可以实现对双泵浦源光束的重叠，一方面可以提高泵浦光束的慢轴方向光束质量，另一方面双泵浦源形成相互备份和高性能余量，避免单个巴条发光点随机失效造成的泵浦异常或失效，解决了采用单个巴条直接耦合的被动调Q固体激光器光束对称性差和可靠性差的问题，满足了高可靠性使用要求。
泵浦模块产生的用于端面泵浦的激励源可入射至晶体模块的左右两侧端面中靠近激励源的一端，以实现端面泵浦的固体激光器，具体的：
在一种优选的实施方式中，上述晶体模块包括增益介质晶体7、饱和吸收晶体8和谐振腔，谐振腔设置于慢轴准直元件5的出光侧，增益介质晶体7和饱和吸收晶体8设置于谐振腔中。本领域技术人员可以根据现有技术对上述增益介质晶体7、饱和吸收晶体8的种类进行合理选取，在此不再赘述。
在另一种优选的实施方式中，上述晶体模块包括增益介质晶体7和饱和吸收晶体8，增益介质晶体7与饱和吸收晶体8形成复合晶体，复合晶体设置于慢轴准直元件5的出光侧，且在慢轴准直元件5的出光方向上，上述复合晶体相对的两个端面形成谐振腔。此时，利用晶体本身的结构形成谐振腔，无需再另外设置谐振腔镜，使激光器的结构更为简单、紧凑。
优选地，上述增益介质晶体7为Nd:YAG、Er:glass和Er:Yb:YAG中的任一种；上述饱和吸收晶体8为Cr:YAG或掺钴尖晶石(Cobalt Spinel)，上述掺钴尖晶石可以为Co:MgAl2O4。但并不局限于上述优选的种类，本领域技术人员可以根据现有技术对上述增益介质晶体7和上述饱和吸收晶体8的种类进行合理选取。更为优选地，上述饱和吸收晶体为Cr:YAG，并和 增益介质晶体Nd:YAG,Yb:YAG一起使用；或者，上述饱和吸收晶体为Co:MgAl2O4，并和增益介质Er，Yb：glass(Er、Yb共掺)一起使用。
本发明的谐振腔可以是两个独立的腔镜组成(高反镜片6和部分反射镜片9)，在能够实现类似目的的情况下，高反镜片6和部分反射镜片9也可以由晶体的两个端面形成，只要这两个端面满足反射率的条件即可。
下面将结合实施例进一步说明本发明的上述泵浦模块及具有其的固体激光器。
实施例1
本实施例采用如图1所示的固体激光器，方案主要包括：
作为双泵浦源1的两个半导体激光器巴条、快轴准直元件2为两个快轴准直透镜、半波片3、偏振合束镜组4、慢轴准直元件5为柱面镜、增益介质晶体7、饱和吸收晶体8以及由高反镜片6和部分反射镜片9组成的谐振腔镜。其中，两个巴条并排放置，分别由快轴准直透镜进行光束的快轴准直；半波片放置在其中一个巴条前端，对该巴条的光束偏振方向实现90°的旋转；偏振度经过90度旋转的光束与另一个巴条的光束通过偏振合束镜组，合成为同一光束；合成后的光束经过柱面镜进行慢轴方向的压缩汇聚后入射到增益介质晶体端面进行泵浦作用。
上述两个巴条并排放置，且两个巴条在电连接上是串联连接。两个串联的巴条相比一个较长的单个巴条或者两个并联的巴条，一方面需要更小的驱动电流可以实现较大的出光功率，另一方面会减小系统中的热负载。
并且，上述偏振合束镜组(PBC)可以实现对作为双泵浦源的两个巴条光束的重叠，一方面可以提高泵浦光束的慢轴方向光束质量，另一方面双泵浦源形成相互备份和高性能余量，避免单个巴条发光点随机失效造成的泵浦异常或失效，可以满足高可靠性使用要求。
从以上的描述中，可以看出，本发明上述的实施例实现了如下技术效果：
1、上述泵浦模块中由于采取两个泵浦源并排设置后进行偏振合束得到单光斑的泵浦光源；在双泵浦源的条件下，偏振合束元件能够实现对双泵浦源输出光束的重叠，一方面可以提高泵浦光束的慢轴方向光束质量，另一方面双泵浦源形成相互备份和高性能余量，避免了单个泵浦源发光点随机失效造成的泵浦源异常或失效，从而能够满足高可靠性使用要求；
2、通过改进慢轴准直元件中偏振合束镜组(PBC)结构尺寸以及采用泵浦源与PBC的特殊排布设计，弥补了由于慢轴发散角引起的偏振合束的光通量损失，从而能够省去现有技术中的光束转换模块(BTS)；由于未采用BTS，因此可以使用具有较多发光点的泵浦源实现高峰值功率应用需求；
3、由于现有的被动调Q固体激光器方案一般采用光纤耦合模块作为泵浦源，或者采用单个巴条出光直接耦合至晶体进行泵浦，从而易导致体积庞大以及出光不均匀的问题。而本发明的上述泵浦模块中采用了改进的偏振合束技术，解决了传统偏振合束方案只能使用较少发 光点的巴条、需要使用BTS导致光学系统复杂庞大的缺点，使得改进后的偏振合束方案体积紧凑、光通量损失小，可应用于对体积和效率要求严格的小型被动调Q端面泵浦固体激光器中。
以上所述仅为本发明的优选实施例而已，并不用于限制本发明，对于本领域的技术人员来说，本发明可以有各种更改和变化。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (16)

  1. 一种泵浦模块，其特征在于，包括：
    泵浦源(1)，所述泵浦源(1)为两个且并排设置，用于提供第一激光和第二激光；
    快轴准直元件(2)，设置于所述泵浦源(1)的出光侧，用于对所述第一激光和所述第二激光进行快轴准直；
    偏振合束元件，设置于所述快轴准直元件(2)的出光侧，用于使快轴准直后的所述第一激光与所述第二激光的偏振方向相互垂直并进行合束以得到第三激光；
    慢轴准直元件(5)，设置于所述偏振合束元件的出光侧，用于对所述第三激光进行慢轴压缩和汇聚以得到激励源。
  2. 根据权利要求1所述的泵浦模块，其特征在于，所述偏振合束元件包括：
    半波片(3)，设置于所述快轴准直元件(2)的出光侧，用于对快轴准直后的所述第一激光的偏振方向进行90°旋转；
    偏振合束镜组(4)，设置于所述半波片(3)的出光侧，用于将旋转后的所述第一激光与快轴准直后的所述第二激光进行合束得到所述第三激光。
  3. 根据权利要求2所述的泵浦模块，其特征在于，两个所述泵浦源(1)分别为提供所述第一激光的第一泵浦源(11)以及提供所述第二激光的第二泵浦源(12)，所述偏振合束镜组(4)包括：
    第一透镜部(41)，位于所述第一泵浦源(11)的出光侧并与所述第一泵浦源(11)相对设置；
    第二透镜部(42)，位于所述第二泵浦源(12)的出光侧并与所述第二泵浦源(12)相对设置，
    所述第一透镜部(41)用于将所述第一激光全部反射至所述第二透镜部(42)的位置处，所述第二透镜部(42)用于全部反射所述第一激光并全部透射所述第二激光。
  4. 根据权利要求3所述的泵浦模块，其特征在于，所述第一泵浦源(11)与所述第二泵浦源(12)的排列方向为第一方向，在所述第一方向上，所述第一泵浦源(11)相对的两个端面之间的垂直距离为L 1，所述第一透镜部(41)相对的两个端部之间的垂直距离为H 1，所述第二泵浦源(12)相对的两个端面之间的垂直距离为L 2，所述第二透镜部(42)相对的两个端部之间的垂直距离为H 2，L 1＜H 1，L 2＜H 2；所述L 1的中点为A 1，所述H 1的中点为B 1，所述L 2的中点为A 2，所述H 2的中点为B 2，所述A 1与所述B 1的连线垂直于所述第一方向。
  5. 根据权利要求1所述的泵浦模块，其特征在于，所述泵浦源(1)串联设置。
  6. 根据权利要求1至5中任一项所述的泵浦模块，其特征在于，所述泵浦源(1)为激光巴条。
  7. 根据权利要求1所述的泵浦模块，其特征在于，所述快轴准直元件(2)为两个且与所述泵浦源(1)的出光侧一一对应地设置。
  8. 根据权利要求1或7所述的泵浦模块，其特征在于，所述快轴准直元件(2)和所述慢轴准直元件(5)独立地选自柱面镜、球面镜和非球面镜中的任一种。
  9. 一种泵浦模块，其特征在于，包括：
    泵浦源(1)，所述泵浦源(1)为两个且并排设置，用于提供第一激光和第二激光；
    合束元件，设置于所述泵浦源(1)的出光侧，用于使所述第一激光与所述第二激光进行合束以得到作为激励源的第三激光。
  10. 根据权利要求9所述的泵浦模块，其特征在于，所述合束元件为偏振合束元件，包括：
    半波片(3)，设置于所述第一激光的出光处，用于对所述第一激光的偏振方向进行90°旋转；
    偏振合束镜组(4)，设置于所述半波片(3)的出光侧，用于将旋转后的所述第一激光与所述第二激光进行合束得到所述第三激光。
  11. 根据权利要求10所述的泵浦模块，其特征在于，所述泵浦模块还包括快轴准直元件和慢轴准直元件；
    所述快轴准直元件(2)设置于所述泵浦源(1)的出光侧，用于对所述第一激光和所述第二激光进行快轴准直；
    所述慢轴准直元件(5)设置于所述合束元件的出光侧，用于对所述第三激光进行慢轴压缩和汇聚以得到激励源；
    优选地，所述快轴准直元件(2)为两个且与所述泵浦源(1)的出光侧一一对应地设置；
    优选地，所述快轴准直元件(2)和所述慢轴准直元件(5)独立地选自柱面镜、球面镜和非球面镜中的任一种。
  12. 根据权利要求9所述的泵浦模块，其特征在于，所述泵浦源(1)串联设置。
  13. 根据权利要求9至12中任一项所述的泵浦模块，其特征在于，所述泵浦源(1)为半导体激光巴条，优选所述泵浦源(1)为并排设置的两个二分之一半导体激光巴条，并排设置的各所述二分之一半导体激光巴条为同一个所述半导体激光巴条的一半。
  14. 根据权利要求9至12中任一项所述的泵浦模块，其特征在于，所述泵浦模块还包括导电导热衬底，两个所述半导体激光巴条并排设置并键合在所述导电导热衬底上。
  15. 一种固体激光器，其特征在于，包括：
    权利要求1至8中任一项所述的泵浦模块，或权利要求9至17中任一项所述的泵浦模块，所述泵浦模块用于产生实现端面泵浦的激励源；
    晶体模块，设置于所述泵浦模块中慢轴准直元件(5)的出光侧，用于接收所述激励源并产生激光。
  16. 根据权利要求15所述的固体激光器，其特征在于，
    所述晶体模块包括增益介质晶体(7)、饱和吸收晶体(8)和谐振腔，所述谐振腔设置于所述慢轴准直元件(5)的出光侧，所述增益介质晶体(7)和饱和吸收晶体(8)设置于所述谐振腔中；或者，
    所述晶体模块包括增益介质晶体(7)和饱和吸收晶体(8)，所述增益介质晶体(7)与所述饱和吸收晶体(8)形成复合晶体，所述复合晶体设置于所述慢轴准直元件(5)的出光侧，且在所述慢轴准直元件(5)的出光方向上，所述复合晶体相对的两个端面形成谐振腔。
PCT/CN2019/109560 2018-11-14 2019-09-30 泵浦模块及具有其的固体激光器 WO2020098413A1 (zh)

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