Laser device and power control method, system and computer storage medium thereof

Abstract

The invention provides a laser device and a power control method, system and computer storage medium thereof, belonging to the technical field of lasers. In the laser device, the polarization of a linearly polarized seed light is parallel to the c-axis of a first crystal, and the linearly polarized seed light is amplified; the polarization of the linearly polarized seed light is perpendicular to the c-axis of a second crystal, and the linearly polarized seed light cannot be amplified. The pump current of a first pump light generator is changed to adjust the output power of the laser device; the pump current of a second pump light generator is changed to adjust the thermal focal length of a bonded crystal, so that the laser device has the same thermal focal length at different powers, thereby ensuring that the spot size and divergence angle of the amplified linearly polarized seed light of the first pump light generator remain consistent at different powers.

Description

Technical Field

[0001] The present invention belongs to the technical field of lasers, and in particular relates to a laser device and a power control method, system and computer storage medium thereof. Background Art

[0002] With the rapid development of solid-state lasers, high-energy ultrashort pulse lasers have gradually entered the market and have been widely used in medical and other fields, such as in ranging, tracking, guidance, pulse holography, etc. In actual application scenarios, in order to ensure the stability of the output energy of the pulsed laser, the energy of the pulsed laser needs to be dynamically adjusted so that the original laser light source can achieve stable output after a series of operations.

[0003] The existing technology generally controls the power of the solid-state laser by adjusting the internal pump current of the solid-state laser. However, the solid-state laser has a strong thermal lens effect, and the thermal focal length changes with the power of the pump light, causing the spot size and divergence angle of the final output of the solid-state laser to change with the change of the thermal focal length, which is not conducive to actual processing applications. Summary of the invention

[0004] The present invention provides a laser device and a power control method, system and computer storage medium thereof, so as to solve the problem in the prior art that the thermal focal length of a solid laser changes with the power of a pumping light, resulting in that the size of the spot and the divergence angle of the final output of the solid laser change with the change of the thermal focal length.

[0005] In a first aspect, the present invention provides a laser device, comprising:

[0006] A seed laser, used to generate linearly polarized seed light;

[0007] A first pump light generator is used to generate a first pump light; the first pump light and the seed light intersect at a first dichroic mirror;

[0008] a first dichroic mirror, used for transmitting the first pump light and reflecting the seed light, so as to superimpose and output the first pump light and the seed light;

[0009] a bonded crystal, located on the output optical path of the first dichroic mirror, and used for transmitting the superimposed laser output by the first dichroic mirror; the bonded crystal comprises a first crystal and a second crystal which are bonded to each other and both are a-axis cut, and the polarization direction of the seed laser after being reflected by the first dichroic mirror is parallel to the c-axis of the first crystal and perpendicular to the c-axis of the second crystal;

[0010] A second dichroic mirror, used to reflect and output the superimposed laser light transmitted by the bonded crystal;

[0011] A second pump light generator, used to generate a second pump light coaxial with the first pump light; the second pump light is transmitted to the bonded crystal through the second dichroic mirror;

[0012] The controller is used to control the output power of the first pump light generator and the second pump light generator respectively.

[0013] Optionally, the first pump light generator comprises:

[0014] A first pump source, used to generate a first pump light;

[0015] A first pump lens, including a first collimating lens and a first focusing lens, for adjusting the light spot characteristics of the first pump light;

[0016] The second pump light generator comprises:

[0017] A second pump source, used to generate a second pump light;

[0018] A second pump lens, comprising a second collimating lens and a second focusing lens, for adjusting the light spot characteristics of the second pump light;

[0019] The controller is used to control the output power of the first pump source and the second pump source respectively.

[0020] Optionally, the first crystal and the second crystal are both nd:yvo4 crystals.

[0021] In a second aspect, the present invention provides a power control method of the laser device according to the first aspect, comprising:

[0022] Obtaining the thermal focal length of the first crystal and the power of the first pump light under different pump currents of the first pump light generator, so as to fit the curves of the pump current of the first pump light generator and the first pump light power and the curve of the thermal focal length;

[0023] Obtaining the thermal focal length of the second crystal corresponding to the second pump light generator under different pump currents to fit a curve of the pump current and the thermal focal length of the second pump light generator;

[0024] When the first pump light generator outputs the maximum pump light power, the thermal focal length corresponding to the first crystal is obtained from a curve of the pump current of the first pump light generator and the first pump light power, and a curve of the pump current of the first pump light generator and the thermal focal length, so as to serve as the focal length after the first crystal and the second crystal are superimposed;

[0025] Acquire the current thermal focal length of the first crystal and the pump current of the first pump light generator corresponding to the current thermal focal length of the first crystal; wherein the pump current of the first pump light generator corresponding to the current thermal focal length of the first crystal is used as the first current;

[0026] Determine the current thermal focal length of the second crystal according to the current thermal focal length of the first crystal and the focal lengths of the two crystals after superposition, so as to serve as the current compensated thermal focal length of the second crystal;

[0027] From the curve of the pump current and thermal focal length of the second pump light generator, the pump current of the second pump light generator corresponding to the currently compensated thermal focal length is obtained, and the first current and the second current are matched to adjust the power of the first pump light without changing the parameters of the amplified linear polarized seed light; wherein the second current is the pump current of the second pump light generator corresponding to the currently compensated thermal focal length.

[0028] Optionally, the obtaining of the thermal focal length of the first crystal and the power of the first pump light under different pump currents of the first pump light generator to fit the curves of the pump current of the first pump light generator and the first pump light power and the curve of the thermal focal length includes:

[0029] Calculate the current thermal focal length f1 of the first crystal according to the following formula:

[0030] ;

[0031] Wherein, n0 is the refractive index of the first crystal when the power of the first pump light generator is 0; n t is the current refractive index of the first crystal; is the rate of change of the refractive index of the first crystal with temperature; P is the current power of the first pump light; Q is the heat generated by the first crystal per unit volume; η is the absorption efficiency of the first crystal for the pump light; T is the current temperature of the first crystal; ▽T represents the gradient of T; d(·) represents differential operation.

[0032] Optionally, determining the current thermal focal length of the second crystal according to the current thermal focal length of the first crystal and the focal length of the two crystals after superposition, as the current compensated thermal focal length of the second crystal, includes:

[0033] Calculate the currently compensated thermal focal length f2 according to the following formula:

[0034] ;

[0035] Wherein, f1 is the current thermal focal length of the first crystal; F is the focal length of the two bonded crystals after superposition.

[0036] In a third aspect, the present invention provides a power control system based on the laser device according to the first aspect, comprising:

[0037] A first acquisition module is used to acquire the thermal focal length of the first crystal and the power of the first pump light under different pump currents of the first pump light generator, so as to fit the curves of the pump current of the first pump light generator and the first pump light power and the curve of the thermal focal length;

[0038] A second acquisition module is used to acquire the thermal focal length of the second crystal corresponding to the second pump light generator under different pump currents, so as to fit a curve of the pump current and the thermal focal length of the second pump light generator;

[0039] a third acquisition module, configured to acquire, when the first pump light generator outputs a maximum pump light power, a thermal focal length corresponding to the first crystal from a curve of a pump current of the first pump light generator and a first pump light power, and a curve of a pump current of the first pump light generator and a thermal focal length, so as to serve as a focal length after the first crystal and the second crystal are superimposed;

[0040] A fourth acquisition module is used to acquire the current thermal focal length of the first crystal and the pump current of the first pump light generator corresponding to the current thermal focal length of the first crystal; wherein the pump current of the first pump light generator corresponding to the current thermal focal length of the first crystal is used as the first current;

[0041] A determination module, used to determine the current thermal focal length of the second crystal according to the current thermal focal length of the first crystal and the focal lengths of the two crystals after superposition, so as to serve as the current compensated thermal focal length of the second crystal;

[0042] The fifth acquisition module is used to obtain the pump current of the second pump light generator corresponding to the currently compensated thermal focal length from the curve of the pump current and thermal focal length of the second pump light generator, and to match the first current and the second current to adjust the power of the first pump light without changing the parameters of the amplified linear polarized seed light; wherein the second current is the pump current of the second pump light generator corresponding to the currently compensated thermal focal length.

[0043] Optionally, the first acquisition module includes:

[0044] The first calculation unit is used to calculate the current thermal focal length f1 of the first crystal according to the following formula:

[0045] ;

[0046] Wherein, n0 is the refractive index of the first crystal when the power of the first pump light generator is 0; n t is the current refractive index of the first crystal; is the rate of change of the refractive index of the first crystal with temperature; P is the current power of the first pump light; Q is the heat generated by the first crystal per unit volume; η is the absorption efficiency of the first crystal for the pump light; T is the current temperature of the first crystal; ▽T represents the gradient of T; d(·) represents differential operation.

[0047] Optionally, the determining module includes:

[0048] The second calculation unit is used to calculate the current compensated thermal focal length f2 according to the following formula:

[0049] ;

[0050] Wherein, f1 is the current thermal focal length of the first crystal; F is the focal length of the two bonded crystals after superposition.

[0051] In a fourth aspect, the present invention provides a computer-readable storage medium for storing a computer program; when the computer program is executed by a processor, the steps of the power control method described in the second aspect are implemented.

[0052] The present invention provides a laser device and a power control method, system and computer storage medium thereof. In the laser device, the polarization of seed light is parallel to the c-axis of a first crystal, and the seed light is amplified; the polarization of the seed light is perpendicular to the c-axis of a second crystal, and the seed light cannot be amplified. The pump current of a first pump light generator is changed to adjust the output power of the laser device; the pump current of a second pump light generator is changed to adjust the thermal focal length of a bonded crystal, so that the laser device has the same thermal focal length at different powers, thereby ensuring that the spot size and divergence angle of the amplified linearly polarized seed light of the first pump light generator remain consistent at different powers. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0054] Figure 1 A schematic diagram of the structure of a laser device provided by an embodiment of the present invention;

[0055] Figure 2 A schematic diagram of a flow chart of a laser device power control method provided by an embodiment of the present invention;

[0056] Figure 3 A diagram of beam parameters when 50W outputs 100W pump provided by an embodiment of the present invention;

[0057] Figure 4The beam distribution diagram of the 50W output 100W pump provided in the embodiment of the present invention;

[0058] Figure 5 A beam parameter diagram of a 35W output 70W pump provided in an embodiment of the present invention;

[0059] Figure 6 The beam distribution diagram of the embodiment of the present invention when the 35W output is 70W pump;

[0060] Figure 7 A beam parameter diagram after thermal focal length compensation provided by an embodiment of the present invention;

[0061] Figure 8 A beam distribution diagram after thermal focal length compensation provided by an embodiment of the present invention;

[0062] Fig. 9 A schematic diagram of the structure of a laser device power control system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0063] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0064] like Figure 1 As shown, this embodiment provides a laser device, including:

[0065] The seed laser 1 is used to generate linearly polarized seed light.

[0066] The first pump light generator is used to generate a first pump light; the first pump light and the seed light intersect at the first dichroic mirror.

[0067] The first dichroic mirror 2 is used for transmitting the first pump light and reflecting the seed light, so as to superimpose the first pump light and the seed light and output them.

[0068] A bonded crystal is located on the output optical path of the first dichroic mirror and is used to transmit the superimposed laser output by the first dichroic mirror 2; the bonded crystal includes a first crystal 3 and a second crystal 4 which are bonded to each other and both are a-axis cut, and the polarization direction of the seed laser after being reflected by the first dichroic mirror 2 is parallel to the c-axis of the first crystal 3 and perpendicular to the c-axis of the second crystal 4; illustratively, the c-axis direction of the first crystal is perpendicular to the c-axis direction of the second crystal.

[0069] The second dichroic mirror 5 is used to reflect and output the superimposed laser light transmitted by the bonded crystal.

[0070] The second pump light generator is used to generate a second pump light coaxial with the first pump light; the second pump light is transmitted through the second dichroic mirror 5 to the bonded crystal.

[0071] The controller 6 is used to control the output power of the first pump light generator and the second pump light generator respectively.

[0072] Exemplarily, the first pump light generator includes:

[0073] The first pump source 7 is used to generate a first pump light.

[0074] The first pump lens, including a first collimating lens 8 and a first focusing lens 9, is used to adjust the light spot characteristics of the first pump light.

[0075] The second pump light generator comprises:

[0076] The second pump source 10 is used to generate a second pump light.

[0077] The second pump lens includes a second collimating lens 11 and a second focusing lens 12, and is used to adjust the spot characteristics of the second pump light.

[0078] The controller 6 is used to control the output power of the first pump source 7 and the second pump source 10 respectively.

[0079] In the present embodiment, the seed laser 1 outputs low-power linearly polarized seed light, which is reflected by the first dichroic mirror 2 and enters the first crystal 3 and the second crystal 4; the first crystal 3 and the second crystal 4 in the present embodiment are both ND:YVO4 crystals, and can also be replaced with other crystals with the same properties as the ND:YVO4 crystals according to actual requirements; the first pump source 7 is a semiconductor laser of 808nm, 878nm or 888nm, and the first pump source 7 emits pump light (first pump light) which passes through the first collimating lens 8, the first focusing lens 9 and the first dichroic mirror 2 in sequence, and then overlaps with the linearly polarized seed light and enters the first crystal 3 and the second crystal 4.

[0080] The second pump source 10 is a semiconductor laser of 808nm, 878nm or 888nm. The second pump source 10 emits pump light (second pump light), which passes through the second collimating lens 11, the second focusing lens 12 and the second dichroic mirror 5 in sequence, and then coincides with the linearly polarized seed light and enters the second crystal 4 and the first crystal 3; the a-axis of the first crystal 3 is parallel to the polarization of the linearly polarized seed light, and the first crystal 3 has an amplifying effect on the linearly polarized seed light; the linearly polarized seed light is perpendicular to the c-axis of the second crystal, and the second crystal 4 has no amplifying effect on the linearly polarized seed light. The second crystal 4 is used to act as a lens with adjustable focal length to compensate for the thermal focal length change of the two crystals caused by changing the output power of the first pump source 7; the second dichroic mirror 5 is used to reflect the linearly polarized seed light amplified by the first crystal 3.

[0081] In the laser device provided in this embodiment, the polarization of the seed light is parallel to the c-axis of the first crystal 3, and the seed light is amplified; the polarization of the seed light is perpendicular to the c-axis of the second crystal 4, and the seed light cannot be amplified, and the pump current of the first pump source 7 is changed to adjust the output power of the laser device; the pump current of the second pump source 10 is changed to adjust the thermal focal length of the bonded crystal, so that the laser device has the same thermal focal length at different powers, thereby ensuring that the spot size and divergence angle of the amplified linearly polarized seed light of the first pump source 7 remain consistent at different powers. Example 2

[0082] like Figure 2 As shown, this embodiment provides a power control method of the laser device according to Embodiment 1, comprising:

[0083] Step 101, obtaining the thermal focal length of the first crystal and the power of the first pump light under different pump currents of the first pump light generator, so as to fit the curves of the pump current of the first pump light generator and the first pump light power and the curve of the thermal focal length.

[0084] Exemplarily, in this step, the current thermal focal length f1 of the first crystal is calculated according to the following formula:

[0085] .

[0086] Wherein, n0 is the refractive index of the first crystal when the power of the first pump light generator is 0; n t is the current refractive index of the first crystal; t represents time; is the rate of change of the refractive index of the first crystal with temperature; P is the current power of the first pump light, that is, the current pump light output power of the first pump source; Q is the heat generated in the unit volume of the first crystal under the action of power P; η is the absorption efficiency of the first pump crystal to the pump light; T is the current temperature of the first crystal; ▽T represents the gradient of T; d(·) represents differential operation. The temperature gradient in the crystal volume is integrated. The temperature gradient reflects the spatial variation of the temperature inside the crystal. The integral result represents the overall thermal effect caused by the uneven temperature inside the crystal. The curve of the pump current of the first pump light generator and the first pump light power shows the corresponding pump light output power of the first pump source at different pump currents; similarly, the curve of the pump current of the first pump light generator and the thermal focal length shows the corresponding thermal focal length (of the first crystal) of the first pump source at different pump currents.

[0087] Step 102 : obtaining the thermal focal length of the second crystal corresponding to the second pump light generator under different pump currents, so as to fit a curve of the pump current and the thermal focal length of the second pump light generator.

[0088] The pump current and thermal focal length curve of the second pump source shows the thermal focal length (of the second crystal) corresponding to different pump currents of the second pump source.

[0089] Step 103, when the first pump light generator outputs the maximum pump light power, from the curve of the pump current of the first pump light generator and the first pump light power, and the curve of the pump current of the first pump light generator and the thermal focal length, obtain the thermal focal length corresponding to the first crystal as the focal length after the first crystal and the second crystal are superimposed.

[0090] In this step, first, from the curve of the pump current of the first pump light generator and the first pump light power, the pump current corresponding to when the first pump source outputs the maximum pump light power is found, and then from the pump current and thermal focal length curve, the thermal focal length (of the first crystal) corresponding to the pump current at this time (the pump current corresponding to when the first pump source outputs the maximum pump light power) is found.

[0091] Step 104, obtaining the current thermal focal length of the first crystal and the pump current of the first pump light generator corresponding to the current thermal focal length of the first crystal; wherein the pump current of the first pump light generator corresponding to the current thermal focal length of the first crystal is used as the first current.

[0092] Step 105 , determining the current thermal focal length of the second crystal according to the current thermal focal length of the first crystal and the focal lengths of the two crystals after superposition, to serve as the current compensated thermal focal length of the second crystal.

[0093] Exemplarily, the currently compensated thermal focal length f2 is calculated according to the following formula:

[0094] .

[0095] Wherein, f1 is the current thermal focal length of the first crystal; F is the focal length of the two bonded crystals after superposition.

[0096] Step 106, obtaining the pump current of the second pump light generator corresponding to the currently compensated thermal focal length from the curve of the pump current and thermal focal length of the second pump light generator, and matching the first current and the second current to adjust the power of the first pump light without changing the parameters of the amplified linear polarized seed light; wherein the second current is the pump current of the second pump light generator corresponding to the currently compensated thermal focal length.

[0097] In step 101 to step 106, assuming that the maximum output power of the laser device is 50W and a 100W pump is required, the thermal focal length of the first crystal under the current pump (100W pump) is calculated to be 150mm according to the formula. If the laser device needs to reduce the power, a 35W laser and a 70W pump are used, and the thermal focal length of the first crystal is 200mm, after calculation, only a 600mm lens needs to be superimposed to adjust the pump light output power of the first pump source without changing the parameters of the amplified linearly polarized seed light beam.

[0098] like Figure 3 As shown in the figure, the corresponding parameters of the laser device with a maximum output power of 50W and 100W pumping are input into the GaussianBeam software, where n represents the refractive index of the propagation medium (i.e., the refractive index of air in the current scenario), M 2 To describe the parameters of beam quality, Waist refers to the beam waist size, Waist position refers to the position of the beam waist, Rayleigh range refers to the Rayleigh length, and Divergence refers to the half angle of divergence. The crystal close to the first pump source is equivalent to a lens with a focal length of 150mm at 150mm, that is, a lens with a focal length of 150mm is added at 150mm, such as Figure 4 As shown, record the values ​​of the beam waist and divergence angle after the lens.

[0099] like Figure 5 As shown, the corresponding parameters of the laser device output power of 35W and 70W pumping are input into the GaussianBeam software. The thermal focal length of the first crystal under 70W pumping is 200mm. It is only necessary to change the focal length of the lens to 200mm, as shown in Figure 6 As shown in the figure, the divergence angle and beam waist of the 100W pump are compared and found to be quite different.

[0100] like Figure 7 and Figure 8 As shown in the figure, a lens with a focal length of 600mm is added at the 200mm lens, and the beam waist and divergence angle distribution under 100W pump are compared and found to be basically consistent, which proves that the compensation scheme is feasible and the compensation effect is good.

[0101] In summary, the laser device power control method provided in this embodiment compensates for the change in thermal focal length of the amplifying crystal (first crystal) caused by the change in pump current, and realizes the power control of the laser device without increasing the loss and changing the spot parameters of the light beam. Example 3

[0102] Based on the same inventive concept as Example 2, this example provides a power control system for a laser device. Since the principle of solving the problem by this system is similar to the power control system method for a laser device described in Example 2, the implementation of this system can refer to the implementation of the power control system method for a laser device.

[0103] like Fig. 9 As shown, this embodiment provides a power control system based on the laser device described in Embodiment 1, including:

[0104] The first acquisition module 100 is used to acquire the thermal focal length of the first crystal and the power of the first pump light under different pump currents of the first pump light generator, so as to fit the curves of the pump current of the first pump light generator and the first pump light power and the curve of the thermal focal length.

[0105] The second acquisition module 200 is used to acquire the thermal focal length of the second crystal corresponding to the second pump light generator under different pump currents, so as to fit the curve of the pump current and the thermal focal length of the second pump light generator.

[0106] The third acquisition module 300 is used to acquire the thermal focal length corresponding to the first crystal from a curve of the pump current of the first pump light generator and the first pump light power, and a curve of the pump current of the first pump light generator and the thermal focal length when the first pump light generator outputs the maximum pump light power, so as to serve as the focal length after the first crystal and the second crystal are superimposed.

[0107] The fourth acquisition module 400 is used to acquire the current thermal focal length of the first crystal and the pump current of the first pump light generator corresponding to the current thermal focal length of the first crystal; wherein the pump current of the first pump light generator corresponding to the current thermal focal length of the first crystal is used as the first current.

[0108] The determination module 500 is used to determine the current thermal focal length of the second crystal according to the current thermal focal length of the first crystal and the focal lengths of the two crystals after superposition, so as to serve as the current compensated thermal focal length of the second crystal.

[0109] The fifth acquisition module 600 is used to obtain the pump current of the second pump light generator corresponding to the currently compensated thermal focal length from the curve of the pump current and thermal focal length of the second pump light generator, and to match the first current and the second current to adjust the power of the first pump light without changing the parameters of the amplified linear polarized seed light; wherein the second current is the pump current of the second pump light generator corresponding to the currently compensated thermal focal length.

[0110] Exemplarily, the first acquisition module includes:

[0111] The first calculation unit is used to calculate the current thermal focal length f1 of the first crystal according to the following formula:

[0112] ;

[0113] Wherein, n0 is the refractive index of the first crystal when the power of the first pump light generator is 0; n t is the current refractive index of the first crystal; is the rate of change of the refractive index of the first crystal with temperature; P is the current power of the first pump light; Q is the heat generated by the first crystal per unit volume; η is the absorption efficiency of the first crystal for the pump light; T is the current temperature of the first crystal; ▽T represents the gradient of T; d(·) represents differential operation.

[0114] Exemplarily, the determining module includes:

[0115] The second calculation unit is used to calculate the current compensated thermal focal length f2 according to the following formula:

[0116] ;

[0117] Wherein, f1 is the current thermal focal length of the first crystal; F is the focal length of the two bonded crystals after superposition.

[0118] For more specific working processes of the above modules, please refer to the corresponding contents disclosed in Example 2, which will not be repeated here. Example 4

[0119] This embodiment provides a computer device, including a processor and a memory; wherein the processor implements the steps of the power control method of the laser device described in Embodiment 2 when executing a computer program stored in the memory.

[0120] For more specific details of the above method, please refer to the corresponding contents disclosed in Example 2, which will not be repeated here. Example 5

[0121] This embodiment provides a computer-readable storage medium for storing a computer program; when the computer program is executed by a processor, the steps of the power control method for the laser device described in Embodiment 2 are implemented.

[0122] For more specific details of the above method, please refer to the corresponding contents disclosed in Example 2, which will not be repeated here. Example 6

[0123] This embodiment provides a computer program product, including computer executable instructions or a computer program. When the computer executable instructions or the computer program are executed by a processor, the steps of the power control method of the laser device described in Embodiment 2 are implemented.

[0124] For more specific details of the above method, please refer to the corresponding contents disclosed in Example 2, which will not be repeated here.

[0125] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the systems, devices, storage media, and computer program products disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0126] Those skilled in the art can clearly understand that the technology in the embodiments of the present invention can be implemented by means of software plus a necessary general hardware platform. Based on this understanding, the technical solution in the embodiments of the present invention can be essentially or partly contributed to the prior art in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present invention or certain parts of the embodiments.

[0127] In some embodiments, computer executable instructions may be in the form of a program, software, software module, script or code, written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and may be deployed in any form, including as a stand-alone program or as a module, component, subroutine or other unit suitable for use in a computing environment.

[0128] As an example, computer-executable instructions may, but need not, correspond to a file in a file system, may be stored as part of a file storing other programs or data, such as in one or more scripts in a HyperText Markup Language (HTML) document, in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files storing one or more modules, subroutines, or code portions).

[0129] As an example, computer executable instructions may be deployed to be executed on one electronic device, or on multiple electronic devices located at one site, or on multiple electronic devices distributed at multiple sites and interconnected by a communication network.

[0130] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A laser device, characterized in that: include: A seed laser, used to generate linearly polarized seed light; A first pump light generator, used to generate a first pump light; The first pump light and the seed light intersect at the first dichroic mirror; a first dichroic mirror, used for transmitting the first pump light and reflecting the seed light, so as to superimpose and output the first pump light and the seed light; a bonded crystal, located on the output optical path of the first dichroic mirror, and used for transmitting the superimposed laser output by the first dichroic mirror; the bonded crystal comprises a first crystal and a second crystal which are bonded to each other and both are a-axis cut, and the polarization direction of the seed laser after being reflected by the first dichroic mirror is parallel to the c-axis of the first crystal and perpendicular to the c-axis of the second crystal; A second dichroic mirror, used to reflect and output the superimposed laser light transmitted by the bonded crystal; A second pump light generator, used to generate a second pump light coaxial with the first pump light; the second pump light is transmitted to the bonded crystal through the second dichroic mirror; A controller, used to control the output power of the first pump light generator and the second pump light generator respectively; The step of respectively controlling the output powers of the first pump light generator and the second pump light generator comprises: The pump current of the first pump light generator is changed to adjust the output power of the laser device; the pump current of the second pump light generator is changed to adjust the thermal focal length of the bonded crystal to achieve the same thermal focal length of the laser device at different powers.

2. The laser device according to claim 1, characterized in that The first pump light generator comprises: A first pump source, used to generate a first pump light; A first pump lens, including a first collimating lens and a first focusing lens, for adjusting the light spot characteristics of the first pump light; The second pump light generator comprises: A second pump source, used to generate a second pump light; A second pump lens, comprising a second collimating lens and a second focusing lens, for adjusting the light spot characteristics of the second pump light; The controller is used to control the output power of the first pump source and the second pump source respectively.

3. The laser device according to claim 1, characterized in that The first crystal and the second crystal are both nd:yvo4 crystals.

4. A power control method for a laser device according to any one of claims 1 to 3, characterized in that: include: Obtaining the thermal focal length of the first crystal and the power of the first pump light under different pump currents of the first pump light generator, so as to fit the curves of the pump current of the first pump light generator and the first pump light power and the curve of the thermal focal length; Obtaining the thermal focal length of the second crystal corresponding to the second pump light generator under different pump currents to fit a curve of the pump current and the thermal focal length of the second pump light generator; When the first pump light generator outputs the maximum pump light power, the thermal focal length corresponding to the first crystal is obtained from a curve of the pump current of the first pump light generator and the first pump light power, and a curve of the pump current of the first pump light generator and the thermal focal length, so as to serve as the focal length after the first crystal and the second crystal are superimposed; Acquire the current thermal focal length of the first crystal and the pump current of the first pump light generator corresponding to the current thermal focal length of the first crystal; wherein the pump current of the first pump light generator corresponding to the current thermal focal length of the first crystal is used as the first current; Determine the current thermal focal length of the second crystal according to the current thermal focal length of the first crystal and the focal lengths of the two crystals after superposition, so as to serve as the current compensated thermal focal length of the second crystal; From the curve of the pump current and thermal focal length of the second pump light generator, the pump current of the second pump light generator corresponding to the currently compensated thermal focal length is obtained, and the first current and the second current are matched to adjust the power of the first pump light without changing the parameters of the amplified linear polarized seed light; wherein the second current is the pump current of the second pump light generator corresponding to the currently compensated thermal focal length.

5. The power control method according to claim 4, characterized in that: The step of obtaining the thermal focal length of the first crystal and the power of the first pump light under different pump currents of the first pump light generator to fit the curves of the pump current of the first pump light generator and the first pump light power and the curve of the thermal focal length includes: Calculate the current thermal focal length f1 of the first crystal according to the following formula: ； Wherein, n0 is the refractive index of the first crystal when the power of the first pump light generator is 0; n t is the current refractive index of the first crystal; is the rate of change of the refractive index of the first crystal with temperature; P is the current power of the first pump light; Q is the heat generated by the first crystal per unit volume; η is the absorption efficiency of the first crystal for the pump light; T is the current temperature of the first crystal; ▽T represents the gradient of T; d(·) represents differential operation.

6. The power control method according to claim 4, characterized in that: The method of determining the current thermal focal length of the second crystal according to the current thermal focal length of the first crystal and the focal length of the two crystals after superposition, so as to serve as the current compensated thermal focal length of the second crystal, comprises: Calculate the currently compensated thermal focal length f2 according to the following formula: ； Wherein, f1 is the current thermal focal length of the first crystal; F is the focal length of the two bonded crystals after superposition.

7. A power control system based on the laser device according to any one of claims 1 to 3, characterized in that: include: A first acquisition module is used to acquire the thermal focal length of the first crystal and the power of the first pump light under different pump currents of the first pump light generator, so as to fit the curves of the pump current of the first pump light generator and the first pump light power and the curve of the thermal focal length; A second acquisition module is used to acquire the thermal focal length of the second crystal corresponding to the second pump light generator under different pump currents, so as to fit a curve of the pump current and the thermal focal length of the second pump light generator; a third acquisition module, configured to acquire, when the first pump light generator outputs a maximum pump light power, a thermal focal length corresponding to the first crystal from a curve of a pump current of the first pump light generator and a first pump light power, and a curve of a pump current of the first pump light generator and a thermal focal length, so as to serve as a focal length after the first crystal and the second crystal are superimposed; A fourth acquisition module is used to acquire the current thermal focal length of the first crystal and the pump current of the first pump light generator corresponding to the current thermal focal length of the first crystal; wherein the pump current of the first pump light generator corresponding to the current thermal focal length of the first crystal is used as the first current; A determination module, used to determine the current thermal focal length of the second crystal according to the current thermal focal length of the first crystal and the focal lengths of the two crystals after superposition, so as to serve as the current compensated thermal focal length of the second crystal; The fifth acquisition module is used to obtain the pump current of the second pump light generator corresponding to the currently compensated thermal focal length from the curve of the pump current and thermal focal length of the second pump light generator, and to match the first current and the second current to adjust the power of the first pump light without changing the parameters of the amplified linear polarized seed light; wherein the second current is the pump current of the second pump light generator corresponding to the currently compensated thermal focal length.

8. The power control system according to claim 7, characterized in that: The first acquisition module includes: The first calculation unit is used to calculate the current thermal focal length f1 of the first crystal according to the following formula: ； Wherein, n0 is the refractive index of the first crystal when the power of the first pump light generator is 0; n t is the current refractive index of the first crystal; is the rate of change of the refractive index of the first crystal with temperature; P is the current power of the first pump light; Q is the heat generated by the first crystal per unit volume; η is the absorption efficiency of the first crystal for the pump light; T is the current temperature of the first crystal; ▽T represents the gradient of T; d(·) represents differential operation.

9. The power control system according to claim 7, characterized in that: The determination module comprises: The second calculation unit is used to calculate the current compensated thermal focal length f2 according to the following formula: ； Wherein, f1 is the current thermal focal length of the first crystal; F is the focal length of the two bonded crystals after superposition.

10. A computer-readable storage medium, characterized in that: Used to store computer programs; when the computer programs are executed by a processor, the steps of the power control method of the laser device according to any one of claims 4 to 6 are implemented.

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