Multi-wavelength laser output device

Abstract

The invention relates to a multi-wavelength laser output device which comprises a laser light source used for generating fundamental frequency laser; the frequency doubling module is fixedly arranged in an optical path of the fundamental frequency laser, comprises a frequency doubling crystal, a frequency tripling crystal and a frequency quadruple crystal which are arranged in sequence and are fixed in position, and is used for converting the fundamental frequency laser into frequency doubling laser, frequency tripling laser and frequency quadruple laser; the multiple groups of wavelength selection modules respectively correspond to the output of the fundamental frequency laser, the output of the frequency-doubled laser, the output of the frequency-tripled laser and the output of the frequency-quadruplicated laser, and each group of wavelength selection module can be independently cut in or cut out of a light path, is used for selectively enabling the laser with the corresponding wavelength to be formed and coaxially output, and is also used for adjusting the output energy of the laser with the corresponding wavelength; the polarization adjusting module is arranged in front of the frequency tripling crystal, can be cut in or out of the light path independently of the wavelength selection module, and is used for changing the polarization state of the frequency-doubled laser when the frequency-quadruplicated laser is output so as to prevent the generation of the frequency tripled laser; by controlling the cut-in and cut-out of different wavelength selection modules and polarization adjustment modules, the coaxial output of any wavelength from the fundamental frequency laser to the quadruplicated frequency laser is realized, and the output energy is adjustable.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser technology, and in particular to a multi-wavelength laser output device. BACKGROUND

[0002] In the fields of titanium-sapphire pumping, laser peening, atmospheric laser radar, flame combustion fluorescence spectrum and other laser applications, users often need to use lasers of multiple wavelengths for experiments or processing. These applications usually require the laser to be able to output 1064nm fundamental light, 532nm second-harmonic light, 355nm third-harmonic light, 266nm fourth-harmonic light and other multiple wavelengths, and in actual use, the laser energy needs to be adjusted according to different experimental conditions or processing requirements. At the same time, in order to ensure the reliability of experimental data and the consistency of processing quality, users have strict requirements on the long-term stability of laser energy.

[0003] However, the existing multi-wavelength lasers have many shortcomings in meeting the above requirements: Firstly, in terms of wavelength switching, the existing technology usually adopts the method of moving the frequency-doubling crystal to realize the output of different wavelengths. For example, when outputting 266nm fourth-harmonic laser, the third-harmonic crystal needs to be moved out of the light path, and only the fourth-harmonic crystal works. This mechanical moving method inevitably affects the angle tuning state of the crystal, especially considering that the fourth-harmonic crystal is extremely sensitive to angle, repeated movement of the crystal position easily leads to a decrease in output energy and poor long-term stability. Secondly, although some existing schemes adopt a design of fixed frequency-doubling crystal to avoid mechanical movement, the lasers of different wavelengths in such schemes cannot be realized coaxially output, but are output from different output ports of the laser, which brings great inconvenience to the user's use. The user needs to build an external light path system for different output ports. In addition, in the scheme of using fixed crystals to realize multi-wavelength output, in order to avoid the generation of third-harmonic 355nm laser when outputting fourth-harmonic 266nm laser, the existing technology usually adopts the method of adjusting the temperature of the third-harmonic crystal to make it deviate from the phase matching condition. However, this method cannot completely suppress the generation of 355nm laser, and a small amount of third-harmonic light will still be generated. These stray light will have an adverse effect on the energy stability of the fourth-harmonic, and when switching between third-harmonic output and fourth-harmonic output, the system's response speed is reduced by waiting for the warming-up or cooling-down process of the third-harmonic crystal. In the aspect of energy regulation, some solutions directly attenuate the polarization in the 1064nm fundamental light path to regulate the output energy. Although this method has little effect on the energy stability of the 1064nm laser output, the subsequent frequency conversion efficiency is extremely sensitive to the energy fluctuation of the fundamental light. Therefore, the attenuation in the fundamental light path will seriously deteriorate the energy stability of the second, third and fourth harmonic outputs. Another solution is to add a half-wave plate before the second harmonic crystal to attenuate the energy. Although this method can regulate the output energy to a certain extent, it will also significantly deteriorate the energy stability of the frequency-doubled light, which cannot meet the requirements of high-precision experiments and processing.

[0004] In addition, due to the lack of integrated energy regulation devices in existing lasers, users often need to build a polarization energy attenuation system in the external light path to achieve energy regulation and stability. This not only consumes time and effort, increases system cost, but also requires high optical knowledge and debugging ability of the user, which limits the popularization and application of the laser. SUMMARY

[0005] The application discloses a multi-wavelength laser output device, which aims to solve the technical problems in the prior art. The application adopts the following technical solutions: The application discloses a multi-wavelength laser output device, which aims to solve the technical problems in the prior art. The application adopts the following technical solutions: The laser light source is used to generate fundamental laser light. The frequency-doubling module is fixedly arranged in the light path of the fundamental laser light and includes a second harmonic crystal, a third harmonic crystal and a fourth harmonic crystal arranged in sequence and fixed in position, and is used to convert the fundamental laser light into second harmonic laser light, third harmonic laser light and fourth harmonic laser light. The multi-group wavelength selection module corresponds to the outputs of the fundamental laser light, the second harmonic laser light, the third harmonic laser light and the fourth harmonic laser light respectively. Each wavelength selection module can independently cut into or cut out of the light path, and is used to selectively form and coaxially output laser light of a corresponding wavelength, and also used to regulate the output energy of the wavelength laser light. The polarization regulation module is arranged before the third harmonic crystal and can independently cut into or cut out of the light path, and is used to change the polarization state of the second harmonic laser light when the fourth harmonic laser light is output, so as to prevent the generation of third harmonic light. By controlling the cutting in and cutting out of different wavelength selection modules and polarization regulation modules, coaxial output of any wavelength from the fundamental laser light to the fourth harmonic laser light can be realized, and the output energy can be regulated.

[0006] As a preferred technical solution, the plurality of wavelength selection modules and the polarization adjustment module are all realized by independent movable mechanical support structures to cut into or cut out the light path, the movable mechanical support structure comprises a slide rail assembly, each wavelength selection module and the polarization adjustment module are installed on the corresponding slide rail assembly, and the cutting in and cutting out of the light path are realized by the linear movement of the slide rail assembly.

[0007] As a preferred technical solution, the two ends of the slide rail assembly are respectively provided with an upper limit structure and a lower limit structure, the upper limit structure is used to limit the position of the wavelength selection module or the polarization adjustment module when cutting into the light path, and the lower limit structure is used to limit the position of the wavelength selection module or the polarization adjustment module when cutting out the light path, and through the upper limit structure and the lower limit structure, the position accuracy and repeatability of the wavelength selection module and the polarization adjustment module when cutting in and cutting out the light path are ensured.

[0008] As a preferred technical solution, the plurality of wavelength selection modules comprises a first wavelength selection module, and the first wavelength selection module can be integrally cut into or cut out the light path. The first wavelength selection module is arranged in the light path of the fundamental laser before the frequency doubling crystal, and comprises a first 45° mirror, a second 45° mirror, a first half-wave plate and a first polarizer. When the first wavelength selection module cuts into the light path: the first 45° mirror is arranged on the incident light path and is used to reflect the fundamental laser to a direction perpendicular to the incident light path; the second 45° mirror is arranged on the exit light path and is arranged in opposite parallel with the first 45° mirror, and is used to reflect the fundamental laser from the first 45° mirror to the exit light path parallel to the incident light path; the first half-wave plate and the first polarizer are arranged in sequence on the exit light path after the second 45° mirror, the first half-wave plate adjusts the polarization state of the fundamental laser by rotation, and the first polarizer is used to transmit the laser component of a specific polarization direction and block the laser component of other polarization directions, so as to realize the continuous adjustable output energy of the fundamental laser. When the first wavelength selection module cuts out the light path: the first 45° mirror cuts out the incident light path, and the second 45° mirror, the first half-wave plate and the first polarizer cut out the exit light path.

[0009] As a preferred technical solution, the plurality of wavelength selection modules further comprises a second wavelength selection module, and the second wavelength selection module can be integrally cut into or cut out the light path. The second wavelength selection module is arranged in the light path after the frequency doubling crystal, and comprises a first dichroic mirror, a second dichroic mirror, a third dichroic mirror, a second half-wave plate and a second polarizer. When the second wavelength selection module is cut into the light path: the first dichroic mirror and the second dichroic mirror are sequentially arranged on the incident light path, used for separating the fundamental frequency laser and the second harmonic laser, making the second harmonic laser reflect to the direction perpendicular to the incident light path, and making the fundamental frequency laser transmit through; the third dichroic mirror is arranged on the exit light path, used for reflecting the second harmonic laser from the first dichroic mirror to the exit light path; the second half-wave plate and the second polarizer are sequentially arranged on the exit light path after the third dichroic mirror, the second half-wave plate adjusts the polarization state of the second harmonic laser by rotating, and the second polarizer is used for transmitting the laser component of a specific polarization direction and blocking the laser component of other polarization directions, so as to realize the continuous adjustment of the output energy of the second harmonic laser. When the second wavelength selection module is cut out of the light path: the first dichroic mirror and the second dichroic mirror are cut out of the incident light path, and the third dichroic mirror, the second half-wave plate and the second polarizer are cut out of the exit light path.

[0010] As a preferred technical solution, the multiple sets of wavelength selection modules further comprise a third wavelength selection module, the third wavelength selection module can be integrally cut into or cut out of the light path; The third wavelength selection module is arranged in the light path after the third harmonic crystal, comprising a fourth dichroic mirror, a fifth dichroic mirror, a sixth dichroic mirror, a third half-wave plate and a third polarizer; When the third wavelength selection module is cut into the light path: the fourth dichroic mirror and the fifth dichroic mirror are sequentially arranged on the incident light path, used for separating the third harmonic laser from the fundamental frequency laser and the second harmonic laser, making the third harmonic laser reflect to the direction perpendicular to the incident light path, and making the fundamental frequency laser and the second harmonic laser transmit through; the sixth dichroic mirror is arranged on the exit light path, used for reflecting the third harmonic laser from the fourth dichroic mirror to the exit light path; the third half-wave plate and the third polarizer are sequentially arranged on the exit light path after the sixth dichroic mirror, the third half-wave plate adjusts the polarization state of the third harmonic laser by rotating, and the third polarizer is used for transmitting the laser component of a specific polarization direction and blocking the laser component of other polarization directions, so as to realize the continuous adjustment of the output energy of the third harmonic laser. When the third wavelength selection module is cut out of the light path: the fourth dichroic mirror and the fifth dichroic mirror are cut out of the incident light path, and the sixth dichroic mirror, the third half-wave plate and the third polarizer are cut out of the exit light path.

[0011] As a preferred technical solution, the multiple sets of wavelength selection modules further comprise a fourth wavelength selection module, the fourth wavelength selection module can be integrally cut into or cut out of the light path; The fourth wavelength selection module is arranged in the light path after the fourth harmonic crystal, comprising a seventh dichroic mirror, an eighth dichroic mirror, a fourth half-wave plate and a fourth polarizer; When the fourth wavelength selection module enters the optical path: the seventh dichroic mirror is placed on the incident optical path to separate the fourth harmonic laser from the fundamental and second harmonic lasers, causing the fourth harmonic laser to be reflected in a direction perpendicular to the incident optical path, allowing the fundamental and second harmonic lasers to pass through; the eighth dichroic mirror is placed on the output optical path to reflect the fourth harmonic laser from the seventh dichroic mirror to the output optical path; the fourth half-wave plate and the fourth polarizer are sequentially placed on the output optical path after the eighth dichroic mirror. The fourth half-wave plate adjusts the polarization state of the fourth harmonic laser by rotation, and the fourth polarizer transmits laser components with specific polarization directions and blocks laser components with other polarization directions, thereby achieving continuous adjustment of the fourth harmonic laser output energy; When the fourth wavelength selection module cuts out the optical path: the seventh dichroic mirror cuts out the incident optical path, and the eighth dichroic mirror, the fourth half-wave plate, and the fourth polarizer cut out the outgoing optical path.

[0012] As a preferred technical solution, the polarization adjustment module includes a fifth half-wave plate and is configured to synchronously enter or exit the optical path with the fourth wavelength selection module; The fifth half-wave plate is used to change the polarization state of the second-harmonic laser, so that the second-harmonic laser after the polarization state change and the residual fundamental laser do not undergo third-harmonic conversion in the third-harmonic crystal.

[0013] As a preferred technical solution, it also includes multiple beam absorbers, each positioned at a different location to absorb the blocked laser energy: The first beam absorber is disposed above the first polarizer and is used to absorb the polarization component of the fundamental frequency laser blocked by the first polarizer. The second beam absorber is positioned above the second polarizer and is used to absorb the polarization component of the second-harmonic laser that is blocked by the second polarizer. The third beam absorber is positioned above the third polarizer and is used to absorb the polarization component of the third-harmonic laser that is blocked by the third polarizer. The fourth beam absorber is positioned above the fourth polarizer and is used to absorb the polarization component of the fourth-harmonic laser light that is blocked by the fourth polarizer. The fifth beam absorber is located at the end of the incident light path and is used to absorb residual fundamental and second-harmonic laser light.

[0014] As a preferred technical solution, a sixth half-wave plate and an output window plate are also included; The sixth half-wave plate is placed in the optical path between the laser source and the first 45° reflector to adjust the polarization direction of the fundamental frequency laser to vertical polarization and allow it to enter the subsequent optical path; The output window is located at the end of the outgoing optical path to seal the optical system and allow laser output.

[0015] One embodiment of the above invention has the following advantages or beneficial effects: This invention primarily provides a multi-wavelength laser output device. By setting up multiple wavelength selection modules that can be switched in or out of the optical path, it achieves coaxial output of a 1064nm fundamental frequency laser, a 532nm frequency-second laser, a 355nm frequency-third laser, and a 266nm frequency-fourth laser. Each wavelength selection module can independently switch in or out of the optical path, allowing the device to flexibly select to output a single wavelength or multiple wavelengths of laser light according to actual needs. Compared to traditional fixed-wavelength laser devices or devices that require changing optical components to change the output wavelength, this invention significantly improves operational convenience and work efficiency.

[0016] Each wavelength selection module adopts a combination structure of dichroic mirror (or 45° reflector), half-wave plate and polarizer. By adjusting the polarization state by rotating the half-wave plate and selectively transmitting through the polarizer, the output energy of each wavelength laser is continuously adjustable from 0 to full energy, and the output energy stability is not affected by the manual adjustment process, thus meeting the precise control requirements of laser energy in different application scenarios.

[0017] The frequency doubling crystal in this invention does not need to participate in the switching movement, ensuring the long-term stability of the output energy. When a fourth-harmonic laser is required, the polarization adjustment module enters the optical path and changes the polarization state of the second-harmonic laser, preventing it from undergoing third-harmonic conversion with the residual fundamental laser in the third-harmonic crystal. This ensures that more second-harmonic laser enters the fourth-harmonic crystal for fourth-harmonic conversion, improving the output efficiency of the fourth-harmonic laser. In addition, by setting beam absorbers at each polarizer, stray light interference is effectively prevented, improving the stability of the device and the quality of the output beam. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below, forming part of the present invention. The illustrative embodiments of the present invention and their descriptions explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings: Figure 1 This is a schematic diagram of the structure of a multi-wavelength laser output device disclosed in one embodiment of the present invention.

[0019] Explanation of reference numerals in the attached figures: 1. Sixth half-wave plate, 2. First 45° reflector, 3. Second 45° reflector, 4. First half-wave plate, 5. First polarizer, 6. Second harmonic crystal, 7. First dichroic mirror, 8. Second dichroic mirror, 9. Third dichroic mirror, 10. Second half-wave plate, 11. Second polarizer, 12. Fifth half-wave plate, 13. Third harmonic crystal, 14. Fourth dichroic mirror, 15. Fifth dichroic mirror, 16. Sixth dichroic mirror, 17. Third half-wave plate, 18. Third polarizer, 19. Fourth harmonic crystal, 20. Seventh dichroic mirror, 21. Eighth dichroic mirror, 22. Fourth half-wave plate, 23. Fourth polarizer, 24. Output window, 25. First beam absorber, 26. Second beam absorber, 27. Third beam absorber, 28. Fourth beam absorber, 29. Fifth beam absorber, 30. Guiding indicator light source. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. In the description of this invention, it should be noted that the term "or" is generally used to include the meaning of "and / or," unless otherwise expressly indicated.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. Furthermore, in the description of this application, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, the terms "S1 surface" and "S2 surface" are used to distinguish two opposing surfaces of an optical element, where "S1 surface" refers to the first surface of the optical element, i.e., the surface on which incident light first illuminates; and "S2 surface" refers to the second surface of the optical element, i.e., the other surface opposite to the S1 surface, from which light enters the optical element and exits. By depositing different optical thin films on the S1 and S2 surfaces, specific optical functions can be achieved.

[0022] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] refer to Figure 1To address the problems existing in the prior art, this invention provides a multi-wavelength laser output device. The device includes a laser source, a frequency doubling module, multiple wavelength selection modules, and a polarization adjustment module. The laser source generates a fundamental frequency laser. The frequency doubling module is fixedly disposed in the optical path of the fundamental frequency laser and includes a second-harmonic crystal 6, a third-harmonic crystal 13, and a fourth-harmonic crystal 19 arranged sequentially and maintaining fixed positions, used to convert the fundamental frequency laser into second-harmonic, third-harmonic, and fourth-harmonic lasers, respectively. The multiple wavelength selection modules correspond to the fundamental frequency laser, second-harmonic laser, third-harmonic laser, and fourth-harmonic laser, respectively. In terms of light output, each wavelength selection module can independently enter or exit the optical path to selectively form and coaxially output laser of the corresponding wavelength, and also to adjust the output energy of the laser of that wavelength; the polarization adjustment module is set before the third harmonic crystal 13 and can independently enter or exit the optical path from the wavelength selection module, and is used to change the polarization state of the second harmonic laser when the fourth harmonic laser is output to prevent the generation of third harmonic light; preferably, by controlling the entry and exit of different wavelength selection modules and polarization adjustment modules, coaxial output of any wavelength from the fundamental frequency laser to the fourth harmonic laser can be achieved, and the output energy is adjustable.

[0024] In a preferred embodiment, the laser source is used to generate a fundamental frequency laser, preferably an infrared laser with a wavelength of 1064 nm. This wavelength has good frequency doubling characteristics and can be efficiently converted into short-wavelength lasers such as 532 nm, 355 nm, and 266 nm. In other optional embodiments, the laser source can also generate other infrared band lasers suitable for frequency doubling, which will not be listed here. The laser source can be of various forms, such as a solid-state laser, a fiber laser, or a semiconductor laser, and its output power, pulse width, repetition frequency, and other parameters can be selected and set according to the needs of the actual application scenario. For example, in applications requiring high peak power, nanosecond or picosecond pulsed lasers can be selected; in applications requiring high average power, continuous or quasi-continuous lasers with high repetition frequencies can be selected. This invention does not particularly limit the specific type and parameters of the laser source, as long as it can generate a fundamental frequency laser suitable for frequency doubling.

[0025] In a preferred embodiment, the second-harmonic crystal 6, the third-harmonic crystal 13, and the fourth-harmonic crystal 19 are arranged sequentially along the incident optical path of the laser source. The second-harmonic crystal 6 is preferably an LBO crystal with a phase matching angle of θ = 90.0°. =10.6°, used to achieve the second harmonic conversion of 1064nm(o) + 1064nm(o) → 532nm(e), converting the fundamental frequency laser into a second harmonic laser; the third harmonic crystal 13 adopts an LBO crystal with a phase matching angle of θ=43.6°. =90.0°, used to achieve the sum-frequency third harmonic conversion of 1064nm(o) + 532nm(e) → 355nm(o), mixing the residual fundamental frequency laser with the second harmonic laser to generate the third harmonic laser; the fourth harmonic crystal 19 can be a DKDP crystal or a BBO crystal. When a DKDP crystal is used, the phase matching angle is θ = 90°. =45°, when using a BBO crystal, the phase matching angle is θ=47.7°, both used to achieve the fourth harmonic conversion of 532nm(o) + 532nm(o) → 266nm(e), converting the second harmonic laser into a fourth harmonic laser. All frequency-doubling crystals are tuned with their phase matching angles along the horizontal direction to ensure that the polarization direction of the incident laser matches the principal axis of the crystal, thereby achieving the optimal frequency doubling conversion efficiency. In other embodiments, other types of nonlinear crystals can also be selected, as long as they can achieve the corresponding frequency doubling conversion.

[0026] In a preferred embodiment, a sixth half-wave plate 1 is provided after the laser source and before the first wavelength selection module. This plate is used to adjust the fundamental frequency state of the input fundamental frequency laser to a vertical polarization direction. By rotating the optical axis angle of the sixth half-wave plate 1, the polarization direction of the fundamental frequency laser can be precisely adjusted to match the phase matching condition of the second harmonic crystal 6, thereby obtaining the highest second harmonic conversion efficiency.

[0027] In a preferred embodiment, the wavelength selection module includes a first wavelength selection module, a second wavelength selection module, a third wavelength selection module, and a fourth wavelength selection module arranged sequentially along the optical path. Each wavelength selection module can be completely inserted into or cut out of the optical path. Preferably, the first wavelength selection module is disposed in the optical path of the fundamental frequency laser before the frequency-doubled crystal 6, and includes a first 45° reflector 2, a second 45° reflector 3, a first half-wave plate 4, and a first polarizer 5, corresponding to... Figure 1 The structure of the part highlighted by the red dashed line; the second wavelength selection module is located in the optical path after the frequency-doubled crystal 6, including the first dichroic mirror 7, the second dichroic mirror 8, the third dichroic mirror 9, the second half-wave plate 10, and the second polarizer 11, corresponding to... Figure 1 The structure of the part highlighted by the green dashed line on the left; the third wavelength selection module is located in the optical path after the third harmonic crystal 13 and before the fourth harmonic crystal 19, including the fourth dichroic mirror 14, the fifth dichroic mirror 15, the sixth dichroic mirror 16, the third half-wave plate 17, and the third polarizer 18, corresponding to... Figure 1 The structure of the part highlighted by the blue dashed line; the fourth wavelength selection module is located in the optical path after the fourth frequency harmonic crystal 19, including the seventh dichroic mirror 20, the eighth dichroic mirror 21, the fourth half-wave plate 22, and the fourth polarizer 23, corresponding to... Figure 1 The structure of the part highlighted by the purple dashed line.

[0028] It should be noted that, Figure 1 The dashed box marked "rail limit" indicates the two positions that the corresponding module can reach when moving via the rail assembly. Figure 1 The dashed box at the top center, indicating the position where the corresponding module enters the optical path, represents the position of the optical path. Figure 1 The dashed box at the bottom center, labeled "Slide Rail Limit," indicates the position where the corresponding module cuts out the optical path.

[0029] In a preferred embodiment, the first 45° reflector 2 and the second 45° reflector 3 are both 1064nm high reflectivity mirrors used to reflect the fundamental frequency laser; the first half-wave plate 4 is a 1064nm antireflection half-wave plate used to adjust the polarization state of the fundamental frequency laser; and the first polarizer 5 is a 1064nm polarizer used to selectively transmit laser components with specific polarization directions.

[0030] In a preferred embodiment, a first beam absorber 25 is provided above the first polarizer 5 to absorb the polarization component of the fundamental frequency laser blocked by the first polarizer 5.

[0031] When the first wavelength selection module enters the optical path, the other wavelength selection modules exit the optical path. At this time: the first 45° reflector 2 is set on the incident optical path to reflect the fundamental frequency laser from the laser source at a 45° angle to a direction perpendicular to the incident optical path; the second 45° reflector 3 is set on the outgoing optical path and is set parallel to the first 45° reflector 2 to reflect the fundamental frequency laser from the first 45° reflector 2 again at a 45° angle to the outgoing optical path parallel to the incident optical path; the first half-wave plate 4 and the first polarizer 5 are set sequentially on the outgoing optical path after the second 45° reflector 3. The polarization state of the fundamental frequency laser is adjusted by manually rotating the optical axis angle of the first half-wave plate 4. The transmission axis direction of the first polarizer 5 is fixed in the horizontal direction to transmit the laser component in the horizontal polarization direction and block the laser component in the vertical polarization direction. By rotating the first half-wave plate 4, the power ratio of the fundamental frequency laser transmitted through the first polarizer 5 can be changed. When the angle between the optical axis of the first half-wave plate 4 and the transmission axis of the polarizer is 45°, all the fundamental frequency laser is transmitted and output, achieving full energy output. When the angle is 0° or 90°, the polarization state of the fundamental frequency laser remains vertical, and it is completely blocked by the first polarizer 5 and absorbed by the first beam absorber 25, achieving zero energy output. By continuously adjusting the optical axis angle of the first half-wave plate 4 between 0° and 45°, the output energy of the fundamental frequency laser can be continuously adjusted from full energy to zero. Since the energy adjustment is achieved through polarization beam splitting, it does not change the beam quality and propagation direction of the transmitted laser. Therefore, the stability of the output energy is not affected by the manual adjustment process.

[0032] When the first wavelength selection module cuts out of the optical path: the first 45° reflector 2 completely moves out of the incident optical path, so that the fundamental frequency laser no longer undergoes the first reflection and continues to propagate directly along the original incident optical path; the second 45° reflector 3, the first half-wave plate 4 and the first polarizer 5 move out of the outgoing optical path at the same time, so that the entire first wavelength selection module is completely separated from the optical path.

[0033] In a preferred embodiment, the S1 surfaces of the first dichroic mirror 7, the second dichroic mirror 8, and the third dichroic mirror 9 are all coated with a 532nm high-reflection film and a 1064nm anti-reflection film, and the S2 surfaces are all coated with a 1064nm and a 532nm dual-wavelength anti-reflection film, used to separate the second-harmonic laser from the fundamental laser; the second half-wave plate 10 is a 532nm anti-reflection film half-wave plate, used to adjust the polarization state of the second-harmonic laser; the second polarizer 11 is a 532nm polarizer, used to selectively transmit laser components with specific polarization directions.

[0034] In a preferred embodiment, a second beam absorber 26 is disposed above the second polarizer 11 to absorb the polarization component of the second-harmonic laser blocked by the second polarizer 11.

[0035] When the second wavelength selection module enters the optical path, other wavelength selection modules exit the optical path. At this time, the first dichroic mirror 7 and the second dichroic mirror 8 are sequentially placed on the incident optical path, parallel to each other, to separate the fundamental frequency laser and the second-harmonic laser in the mixed beam after passing through the second-harmonic crystal 6. Specifically, the first dichroic mirror 7 reflects the horizontally polarized second-harmonic laser at a 45° angle to a direction perpendicular to the incident optical path, while allowing the vertically polarized residual fundamental frequency laser to pass through. The function of the second dichroic mirror 8 is to compensate for the optical path translation caused by the first dichroic mirror 7, restoring the transmitted residual fundamental frequency laser to its original optical path position, ensuring the alignment accuracy of the subsequent optical path. The third dichroic mirror 9 is placed on the exit optical path, parallel to the first dichroic mirror 7, to reflect the second-harmonic laser reflected from the first dichroic mirror 7 again at a 45° angle to the exit optical path parallel to the incident optical path. The second half-wave plate 10 and the second polarizer 11 are sequentially arranged in the output light path after the third dichroic mirror 9. The polarization state of the second-harmonic laser is adjusted by manually rotating the optical axis angle of the second half-wave plate 10. The transmission axis direction of the second polarizer 11 is fixed in the horizontal direction, which is used to transmit the laser component in the horizontal polarization direction and block the laser component in the vertical polarization direction. By rotating the second half-wave plate 10, when the angle between its optical axis and the transmission axis of the polarizer is 0°, all the second-harmonic laser light is transmitted and output in a horizontal polarization state, achieving full energy output; when the angle is 45°, the polarization state of the second-harmonic laser light is rotated to the vertical direction, and it is completely blocked by the second polarizer 11 and absorbed by the second beam absorber 26, achieving zero energy output; by adjusting the optical axis angle of the second half-wave plate 10 continuously between 0° and 45°, the output energy of the second-harmonic laser light can be continuously adjusted from full energy to zero. Since the energy adjustment is achieved through polarization beam splitting after the second-harmonic laser light is generated, it does not change the power and state of the fundamental frequency laser. Therefore, the stability of the output energy is not affected by the manual adjustment process.

[0036] When the second wavelength selection module cuts out of the optical path, the first dichroic mirror 7 and the second dichroic mirror 8 move out of the incident optical path simultaneously, so that the mixed beam (including the horizontally polarized second-frequency laser and the vertically polarized residual fundamental frequency laser) after passing through the second-frequency crystal 6 no longer undergoes wavelength separation and continues to propagate directly along the original optical path. The mixed beam can directly enter the subsequent third-frequency crystal 13 for sum-frequency conversion. The third dichroic mirror 9, the second half-wave plate 10, and the second polarizer 11 move out of the outgoing optical path simultaneously, so that the entire second wavelength selection module is completely separated from the optical path.

[0037] In a preferred embodiment, the S1 surfaces of the fourth dichroic mirror 14, the fifth dichroic mirror 15, and the sixth dichroic mirror 16 are all coated with a 355nm high-reflection film and a 1064nm and 532nm dual-wavelength anti-reflection film, and the S2 surfaces are all coated with a 1064nm and 532nm dual-wavelength anti-reflection film, which are used to separate the third-harmonic laser from the residual fundamental and second-harmonic lasers; the third half-wave plate 17 is a 355nm anti-reflection film half-wave plate, which is used to adjust the polarization state of the third-harmonic laser; the third polarizer 18 is a 355nm polarizer, which is used to selectively transmit laser components with specific polarization directions.

[0038] Preferably, a third beam absorber 27 is provided above the third polarizer 18 to absorb the polarization component of the third-harmonic laser blocked by the third polarizer 18.

[0039] When the third wavelength selection module enters the optical path, the other wavelength selection modules exit the optical path. At this time, the fourth dichroic mirror 14 and the fifth dichroic mirror 15 are sequentially arranged on the incident optical path, placed parallel to each other, to separate the third-harmonic laser from the residual fundamental and second-harmonic lasers in the mixed beam after passing through the third-harmonic crystal 13. Specifically, the fourth dichroic mirror 14 reflects the horizontally polarized third-harmonic laser at a 45° angle to a direction perpendicular to the incident optical path, while allowing the vertically polarized residual fundamental and second-harmonic lasers to pass through. The fifth dichroic mirror 15 compensates for the optical path shift caused by the fourth dichroic mirror 14, restoring the transmitted residual fundamental and second-harmonic lasers to their original optical path positions. The sixth dichroic mirror 16 is arranged on the outgoing optical path, parallel to the fourth dichroic mirror 14, to reflect the third-harmonic laser reflected from the fourth dichroic mirror 14 again at a 45° angle to the outgoing optical path parallel to the incident optical path. The third half-wave plate 17 and the third polarizer 18 are sequentially arranged in the output light path after the sixth dichroic mirror 16. The polarization state of the third frequency harmonic laser is adjusted by manually rotating the optical axis angle of the third half-wave plate 17. The transmission axis direction of the third polarizer 18 is fixed in the horizontal direction, which is used to transmit the laser component in the horizontal polarization direction and block the laser component in the vertical polarization direction. By rotating the third half-wave plate 17, when the angle between its optical axis and the transmission axis of the polarizer is 45°, all third-harmonic lasers are transmitted and output in a horizontal polarization state, achieving full-energy output. When the angle is 0° or 90°, the polarization state of the third-harmonic laser remains vertical, and it is completely blocked by the third polarizer 18 and absorbed by the third beam absorber 27, achieving zero-energy output. By continuously adjusting the optical axis angle of the third half-wave plate 17 between 0° and 45°, the output energy of the third-harmonic laser can be continuously adjusted from full energy to zero. Since the energy adjustment is achieved through polarization beam splitting after the third-harmonic laser is generated, it does not change the power and state of the preceding laser. Therefore, the stability of the output energy is not affected by the manual adjustment process.

[0040] When the third wavelength selection module cuts out of the optical path: the fourth dichroic mirror 14 and the fifth dichroic mirror 15 move out of the incident optical path at the same time, so that the mixed beam after passing through the third harmonic crystal 13 no longer undergoes wavelength separation and continues to propagate directly along the original optical path; the sixth dichroic mirror 16, the third half-wave plate 17 and the third polarizer 18 move out of the outgoing optical path at the same time, so that the entire third wavelength selection module is completely separated from the optical path.

[0041] In a preferred embodiment, the S1 surfaces of the seventh dichroic mirror 20 and the eighth dichroic mirror 21 are both coated with a 266nm high-reflection film and a 1064nm and 532nm dual-wavelength anti-reflection film, and the S2 surfaces are both coated with a 1064nm and 532nm dual-wavelength anti-reflection film, which are used to separate the fourth harmonic laser from the residual fundamental and second harmonic lasers; the fourth half-wave plate 22 is a 266nm anti-reflection film half-wave plate, which is used to adjust the polarization state of the fourth harmonic laser; the fourth polarizer 23 is a 266nm polarizer, which is used to selectively transmit laser components with specific polarization directions.

[0042] Preferably, a fourth beam absorber 28 is provided above the fourth polarizer 23 to absorb the polarization component of the fourth-harmonic laser blocked by the fourth polarizer 23.

[0043] When the fourth wavelength selection module enters the optical path, the other wavelength selection modules exit the optical path. At this time: the seventh dichroic mirror 20 is placed on the incident optical path to separate the fourth-harmonic laser from the residual fundamental and second-harmonic lasers in the mixed beam after passing through the fourth-harmonic crystal 19. Specifically, the seventh dichroic mirror 20 reflects the horizontally polarized fourth-harmonic laser at a 45° angle to a direction perpendicular to the incident optical path, while allowing the vertically polarized residual fundamental and second-harmonic lasers to pass through; the eighth dichroic mirror 21 reflects the fourth-harmonic laser reflected from the seventh dichroic mirror 20 at a 45° angle to the outgoing optical path parallel to the incident optical path. The fourth half-wave plate 22 and the fourth polarizer 23 are sequentially placed on the outgoing optical path after the eighth dichroic mirror 21. The fourth half-wave plate 22 adjusts the polarization state of the fourth-harmonic laser by manually rotating its optical axis angle. The transmission axis of the fourth polarizer 23 is fixed in the horizontal direction to transmit the horizontally polarized laser component and block the vertically polarized laser component. By rotating the fourth half-wave plate 22, when the angle between its optical axis and the transmission axis of the polarizer is 0°, all fourth-harmonic lasers are transmitted and output in a horizontal polarization state, achieving full-energy output. When the angle is 45°, the polarization state of the fourth-harmonic laser is rotated to the vertical direction, and it is completely blocked by the fourth polarizer 23 and absorbed by the fourth beam absorber 28, achieving zero-energy output. By continuously adjusting the optical axis angle of the fourth half-wave plate 22 between 0° and 45°, the output energy of the fourth-harmonic laser can be continuously adjusted from full energy to zero. Since the energy adjustment is achieved through polarization beam splitting after the fourth-harmonic laser is generated, it does not change the power and state of the preceding laser. Therefore, the stability of the output energy is not affected by the manual adjustment process.

[0044] When the fourth wavelength selection module cuts out of the optical path: the seventh dichroic mirror 20 moves out of the incident optical path, so that the mixed beam after passing through the fourth frequency doubling crystal 19 no longer undergoes wavelength separation and continues to propagate directly along the original optical path; the eighth dichroic mirror 21, the fourth half-wave plate 22 and the fourth polarizer 23 move out of the outgoing optical path at the same time, so that the entire fourth wavelength selection module is completely separated from the optical path.

[0045] Preferably, the polarization adjustment module includes a fifth half-wave plate 12, that is... Figure 1 The structure of the smaller green dashed box on the right is configured to enter or exit the optical path synchronously with the fourth wavelength selection module; the fifth half-wave plate 12 is used to change the polarization state of the second-harmonic laser so that the second-harmonic laser after the polarization state is changed and the residual fundamental laser does not undergo third-harmonic conversion in the third-harmonic crystal 13.

[0046] Specifically, the fifth half-wave plate 12 is positioned in the optical path before the third-harmonic crystal 13. When the fourth wavelength selection module enters the optical path to output fourth-harmonic laser, the fifth half-wave plate 12 simultaneously enters the optical path. By rotating its optical axis angle to a specific angle, the polarization state of the originally horizontally polarized second-harmonic laser is rotated to vertical polarization, thus aligning it with the polarization direction of the vertically polarized residual fundamental frequency laser. Since third-harmonic conversion requires two lasers with different polarization states (horizontally polarized second-harmonic laser and vertically polarized fundamental frequency laser) to generate third-harmonic laser through a frequency-sum process, when both the second-harmonic laser and the fundamental frequency laser are vertically polarized, they cannot satisfy the phase-matching condition in the third-harmonic crystal 13, and therefore, third-harmonic conversion will not occur. Thus, the beam after the third-harmonic crystal 13 only contains vertically polarized second-harmonic laser and fundamental frequency laser, without generating third-harmonic laser, ensuring that the subsequent fourth-harmonic crystal 19 only receives the laser of the required wavelength for fourth-harmonic conversion, avoiding unnecessary energy loss and optical path interference.

[0047] When the fourth wavelength selection module cuts out the optical path, the fifth half-wave plate 12 simultaneously cuts out the optical path, so that the second-harmonic laser maintains its original horizontal polarization state and undergoes normal sum-frequency conversion with the vertically polarized residual fundamental frequency laser in the third-harmonic crystal 13 to generate the third-harmonic laser.

[0048] In a preferred embodiment, a fifth beam absorber 29 is provided at the end of the incident light path to absorb residual fundamental and second-harmonic laser light.

[0049] Specifically, when the fundamental frequency laser is output, the first wavelength selection module enters the optical path. After the fundamental frequency laser is reflected twice by the first 45° reflector 2 and the second 45° reflector 3, the beam enters the output optical path. All the fundamental frequency laser is output through the output optical path. At this time, no laser propagates to the fifth beam absorber 29 in the incident optical path.

[0050] When the second-harmonic laser is output, the second wavelength selection module enters the optical path. The horizontally polarized second-harmonic laser generated after passing through the second-harmonic crystal 6 is reflected by the first dichroic mirror 7 and enters the output optical path. The residual fundamental frequency laser, which is not fully converted, maintains a vertical polarization state and is transmitted through the first dichroic mirror 7 and the second dichroic mirror 8, continuing to propagate backward along the incident optical path. It passes through the third-harmonic crystal 13 and the fourth-harmonic crystal 19 in sequence (since there is only a single-wavelength vertically polarized fundamental frequency laser, the frequency doubling conversion condition is not met, so no new frequency-doubled light is generated). Finally, it is absorbed by the fifth beam absorber 29 to avoid the residual fundamental frequency laser from interfering with or damaging the optical path.

[0051] When the system outputs third-harmonic laser light, the third wavelength selection module enters the optical path. The horizontally polarized third-harmonic laser light generated after passing through the third-harmonic crystal 13 is reflected by the fourth dichroic mirror 14 and enters the output optical path. The residual fundamental and second-harmonic laser light, which are not fully converted, are transmitted through the fourth and fifth dichroic mirrors 14 and continue to propagate backward along the incident optical path, entering the fourth-harmonic crystal 19. Since fourth-harmonic conversion requires a specific polarization-matched second-harmonic laser light and fundamental laser light, and the polarization states of the two lasers do not meet the phase-matching condition for fourth-harmonic conversion, no fourth-harmonic laser light is generated. These residual laser lights are transmitted through the fourth-harmonic crystal 19 and are eventually absorbed by the fifth beam absorber 29.

[0052] When the fourth-harmonic laser is output, the fourth wavelength selection module and the polarization adjustment module simultaneously enter the optical path. The fifth half-wave plate 12 rotates the polarization state of the second-harmonic laser from horizontal to vertical, making it consistent with the polarization state of the residual fundamental laser. Therefore, the phase-matching condition for sum-frequency conversion is not satisfied in the third-harmonic crystal 13, and no third-harmonic laser is generated. After passing through the third-harmonic crystal 13, the vertically polarized second-harmonic laser and the fundamental laser continue to propagate along the incident optical path into the fourth-harmonic crystal 19, where a horizontally polarized fourth-harmonic laser is generated. The generated fourth-harmonic laser is reflected by the seventh dichroic mirror 20 into the output optical path, while the incompletely converted residual fundamental laser and residual second-harmonic laser are transmitted through the seventh dichroic mirror 20 and finally absorbed by the fifth beam absorber 29.

[0053] In a preferred embodiment, multiple wavelength selection modules and polarization adjustment modules are integrated into or out of the optical path through independent movable mechanical support structures. The movable mechanical support structures include slide rail assemblies, and each wavelength selection module and polarization adjustment module is mounted on a corresponding slide rail assembly. The entry and exit of the optical path are achieved by the linear movement of the slide rail assembly.

[0054] Specifically, taking the wavelength selection module as an example, the optical element of each wavelength selection module is fixedly mounted on an independent mounting platform. This mounting platform is connected to a corresponding slide rail assembly, and smooth linear movement is achieved through the guiding action of the slide rail. The movement direction of the slide rail assembly is perpendicular to the main optical path direction of laser propagation. When a wavelength selection module needs to be inserted into the optical path, the operator manually or electrically drives the mounting platform upward along the slide rail, causing the optical element of that module to enter the predetermined optical path position. When the module needs to be removed from the optical path, the mounting platform is pushed downward in the opposite direction, causing the optical element to completely leave the optical path area. This structure allows each wavelength selection module to be independent of each other, and different modules can be flexibly selected individually or in combination according to actual needs to achieve flexible switching output of multi-wavelength lasers. The movement method of the polarization adjustment module is the same as that of the wavelength selection module, and will not be described further here.

[0055] In a preferred embodiment, the slide rail assembly is provided with an upper limit structure and a lower limit structure at both ends. The upper limit structure is used to limit the position of the wavelength selection module or polarization adjustment module when it enters the optical path, and the lower limit structure is used to limit the position of the wavelength selection module or polarization adjustment module when it exits the optical path. The upper limit structure and the lower limit structure ensure the positional accuracy and repeatability of the wavelength selection module and polarization adjustment module when entering and exiting the optical path.

[0056] Specifically, the upper limit structure uses mechanical limit blocks or positioning pins. When the mounting platform moves upward along the slide rail to the upper limit position, it contacts the upper limit structure and stops moving. At this point, the optical elements of the wavelength selection module are precisely positioned in the designed optical path, ensuring that the incident laser can accurately illuminate the effective working area of ​​the optical elements, guaranteeing the alignment accuracy and optical performance of the optical path. Similarly, the lower limit structure uses mechanical limit blocks or positioning pins. When the mounting platform moves downward to the lower limit position, it contacts the lower limit structure and stops. At this point, all optical elements of the wavelength selection module are completely outside the optical path area, without obstructing or interfering with the passing laser beam. Through the precise positioning of the upper and lower limit structures, even after multiple insertion and exit operations, the position of the wavelength selection module remains highly consistent each time it enters the optical path, avoiding optical path offset or optical performance degradation due to positioning errors, thus improving the stability and reliability of the system. Furthermore, the limit structures also serve a protective function, preventing the mounting platform from moving beyond the safe range and causing mechanical collisions or damage to the optical elements.

[0057] In a preferred embodiment, the front end of the outgoing optical path is further provided with a guiding indicator light source 30, which is used to provide visible light indication when the laser is not working or in the debugging state, so as to facilitate optical path alignment and system debugging; the end of the outgoing optical path is further provided with an output window 24, which is used to close the optical path system and allow laser output.

[0058] Specifically, the guidance indicator light source 30 is typically a low-power laser or LED light source in the visible wavelength range, whose emitted visible light propagates coaxially or nearly coaxially with the main laser beam path. Before starting the laser or during optical path debugging, the operator can turn on the guidance indicator light source 30 and quickly determine whether the optical path is correctly aligned, whether each optical component is in the appropriate position, and whether the direction of the output beam meets the requirements by observing the propagation path and illumination position of the visible indicator light.

[0059] The output window 24 is made of high-quality optical glass material, and both of its surfaces are coated with anti-reflection films for multiple wavelengths, specifically 1064nm, 532nm, 355nm, and 266nm anti-reflection films, to ensure that these four wavelengths of laser light have extremely low reflection loss and high transmittance when passing through the window, with a typical transmittance of over 99%.

[0060] Compared with existing technologies, the device provided in the above embodiments, through an integrated structure of multi-stage frequency doubling conversion and wavelength selection modules, achieves coaxial output of four wavelength lasers—1064nm, 532nm, 355nm, and 266nm—within the same optical path system. Each wavelength laser shares the same incident and output optical paths, and a sliding rail assembly enables flexible switching in and out of different wavelength selection modules, ensuring a fixed laser output port and consistent position, direction, and quality of the output beam. This coaxial output structure eliminates the drawbacks of traditional multi-wavelength lasers requiring multiple output ports or complex optical path switching mechanisms, significantly simplifying the device structure, reducing the difficulty of optical path alignment, facilitating interfacing with external optical systems or application equipment, and significantly improving the integration and ease of use of the laser.

[0061] Of particular importance is that the second-harmonic crystal 6, third-harmonic crystal 13, and fourth-harmonic crystal 19 in the above embodiments are all fixedly installed on the incident light path and do not participate in the mechanical movement during wavelength switching. The selection and switching of wavelengths are achieved entirely through the insertion and removal of optical elements such as dichroic mirrors, half-wave plates, and polarizers in each wavelength selection module. The frequency-harmonic crystals are always in a stable working position and temperature environment. This structure avoids the problems of positional displacement, temperature fluctuation, and changes in phase matching conditions that may be caused by frequent crystal movement in traditional schemes, ensuring the long-term stability of the frequency doubling conversion efficiency. At the same time, since the crystals do not need to bear the stress and vibration caused by mechanical movement, the risk of crystal damage and performance degradation is reduced, extending the lifespan of the crystals and fundamentally guaranteeing the long-term stability and reliability of the laser output energy.

[0062] Furthermore, the above embodiments, by configuring a combination of half-wave plates and polarizers in each wavelength selection module, achieve a continuously adjustable laser energy function based on the principle of polarization beam splitting. The operator can change the polarization state of the laser by manually rotating or electrically driving the half-wave plate. With the help of a polarizer with a fixed transmission axis, any energy output from zero to full energy range can be achieved. Since energy adjustment is achieved through optical polarization beam splitting after each wavelength of laser is generated, without changing the working state, temperature, or laser pump power of the frequency doubling crystal or other pre-stage parameters, the stability of the laser output remains consistent throughout the entire energy adjustment range. Problems such as energy fluctuations, beam quality degradation, or frequency drift that may occur with traditional adjustment methods (such as changing pump power or crystal temperature) will not occur. This allows the laser to maintain excellent stability and consistent beam quality at different output energies, meeting the needs of applications such as precision machining and scientific research where laser stability is critical.

[0063] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

Claims

1. A multi-wavelength laser output device, characterized in that, include: Laser source, used to generate fundamental frequency laser; A frequency doubling module is fixedly disposed in the optical path of the fundamental frequency laser, and includes a second-harmonic crystal, a third-harmonic crystal, and a fourth-harmonic crystal arranged sequentially and kept in a fixed position, for converting the fundamental frequency laser into a second-harmonic laser, a third-harmonic laser, and a fourth-harmonic laser. Multiple wavelength selection modules are provided, corresponding to the outputs of the fundamental frequency laser, the second harmonic laser, the third harmonic laser, and the fourth harmonic laser, respectively. Each wavelength selection module can independently enter or exit the optical path to selectively enable the laser of the corresponding wavelength to be formed and coaxially output, and also to adjust the output energy of the laser of that wavelength. A polarization adjustment module, located before the third harmonic crystal, can independently enter or exit the optical path from the wavelength selection module. It is used to change the polarization state of the second harmonic laser when the fourth harmonic laser is output, so as to prevent the generation of third harmonic light. Specifically, by controlling the entry and exit of different wavelength selection modules and polarization adjustment modules, coaxial output of any wavelength from the fundamental frequency laser to the fourth harmonic laser can be achieved, and the output energy is adjustable.

2. The multi-wavelength laser output device according to claim 1, characterized in that, Multiple wavelength selection modules and polarization adjustment modules are connected to the optical path via independent movable mechanical support structures. Each movable mechanical support structure includes a slide rail assembly. Each wavelength selection module and polarization adjustment module is mounted on the corresponding slide rail assembly. The optical path is connected or disconnected by the linear movement of the slide rail assembly.

3. The multi-wavelength laser output device according to claim 2, characterized in that, The slide rail assembly has an upper limit structure and a lower limit structure at both ends. The upper limit structure is used to limit the position of the wavelength selection module or the polarization adjustment module when entering the optical path, and the lower limit structure is used to limit the position of the wavelength selection module or the polarization adjustment module when exiting the optical path. The upper limit structure and the lower limit structure ensure the positional accuracy and repeatability of the wavelength selection module and the polarization adjustment module when entering and exiting the optical path.

4. The multi-wavelength laser output device according to claim 1, characterized in that, The multiple wavelength selection modules include a first wavelength selection module, which can be completely inserted into or cut out of the optical path; The first wavelength selection module is disposed in the optical path of the fundamental frequency laser before the second harmonic crystal, and includes a first 45° reflector, a second 45° reflector, a first half-wave plate, and a first polarizer. When the first wavelength selection module enters the optical path: the first 45° reflector is disposed on the incident optical path to reflect the fundamental frequency laser to a direction perpendicular to the incident optical path; the second 45° reflector is disposed on the outgoing optical path and is disposed parallel to the first 45° reflector to reflect the fundamental frequency laser from the first 45° reflector to the outgoing optical path parallel to the incident optical path; the first half-wave plate and the first polarizer are disposed sequentially on the outgoing optical path after the second 45° reflector. The first half-wave plate adjusts the polarization state of the fundamental frequency laser by rotation, and the first polarizer transmits laser components with specific polarization directions and blocks laser components with other polarization directions, thereby realizing continuous adjustment of the output energy of the fundamental frequency laser; When the first wavelength selection module cuts out the optical path: the first 45° reflector cuts out the incident optical path, and the second 45° reflector, the first half-wave plate, and the first polarizer cut out the outgoing optical path.

5. The multi-wavelength laser output device according to claim 4, characterized in that, The multiple wavelength selection modules also include a second wavelength selection module, which can be completely inserted into or cut out of the optical path; The second wavelength selection module is located in the optical path after the frequency-doubled crystal, and includes a first dichroic mirror, a second dichroic mirror, a third dichroic mirror, a second half-wave plate, and a second polarizer; When the second wavelength selection module enters the optical path: the first and second dichroic mirrors are sequentially disposed on the incident optical path to separate the fundamental frequency laser and the second harmonic laser, so that the second harmonic laser is reflected in a direction perpendicular to the incident optical path, allowing the fundamental frequency laser to pass through; the third dichroic mirror is disposed on the outgoing optical path to reflect the second harmonic laser from the first dichroic mirror to the outgoing optical path; the second half-wave plate and the second polarizer are sequentially disposed on the outgoing optical path after the third dichroic mirror, the second half-wave plate adjusts the polarization state of the second harmonic laser by rotation, and the second polarizer transmits laser components with specific polarization directions and blocks laser components with other polarization directions, thereby realizing continuous adjustment of the output energy of the second harmonic laser; When the second wavelength selection module cuts out the optical path: the first dichroic mirror and the second dichroic mirror cut out the incident optical path, and the third dichroic mirror, the second half-wave plate and the second polarizer cut out the outgoing optical path.

6. The multi-wavelength laser output device according to claim 5, characterized in that, The multiple wavelength selection modules also include a third wavelength selection module, which can be completely inserted into or cut out of the optical path; The third wavelength selection module is located in the optical path after the third harmonic crystal, and includes a fourth dichroic mirror, a fifth dichroic mirror, a sixth dichroic mirror, a third half-wave plate, and a third polarizer; When the third wavelength selection module enters the optical path: the fourth and fifth dichroic mirrors are sequentially disposed on the incident optical path to separate the third-harmonic laser from the fundamental and second-harmonic lasers, causing the third-harmonic laser to be reflected in a direction perpendicular to the incident optical path, allowing the fundamental and second-harmonic lasers to pass through; the sixth dichroic mirror is disposed on the outgoing optical path to reflect the third-harmonic laser from the fourth dichroic mirror to the outgoing optical path; the third half-wave plate and the third polarizer are sequentially disposed on the outgoing optical path after the sixth dichroic mirror, the third half-wave plate adjusts the polarization state of the third-harmonic laser by rotation, and the third polarizer transmits laser components with specific polarization directions and blocks laser components with other polarization directions, thereby realizing continuous adjustment of the output energy of the third-harmonic laser; When the third wavelength selection module cuts out the optical path: the fourth and fifth dichroic mirrors cut out the incident optical path, and the sixth dichroic mirror, the third half-wave plate, and the third polarizer cut out the outgoing optical path.

7. The multi-wavelength laser output device according to claim 6, characterized in that, The multiple wavelength selection modules also include a fourth wavelength selection module, which can be completely inserted into or cut out of the optical path; The fourth wavelength selection module is located in the optical path after the fourth harmonic crystal, and includes a seventh dichroic mirror, an eighth dichroic mirror, a fourth half-wave plate, and a fourth polarizer. When the fourth wavelength selection module enters the optical path: the seventh dichroic mirror is placed on the incident optical path to separate the fourth harmonic laser from the fundamental and second harmonic lasers, causing the fourth harmonic laser to be reflected in a direction perpendicular to the incident optical path, allowing the fundamental and second harmonic lasers to pass through; the eighth dichroic mirror is placed on the outgoing optical path to reflect the fourth harmonic laser from the seventh dichroic mirror to the outgoing optical path; the fourth half-wave plate and the fourth polarizer are sequentially placed on the outgoing optical path after the eighth dichroic mirror. The fourth half-wave plate adjusts the polarization state of the fourth harmonic laser by rotation, and the fourth polarizer transmits laser components with specific polarization directions and blocks laser components with other polarization directions, thereby achieving continuous and adjustable output energy of the fourth harmonic laser; When the fourth wavelength selection module cuts out the optical path: the seventh dichroic mirror cuts out the incident optical path, and the eighth dichroic mirror, the fourth half-wave plate, and the fourth polarizer cut out the outgoing optical path.

8. The multi-wavelength laser output device according to claim 7, characterized in that, The polarization adjustment module includes a fifth half-wave plate and is configured to synchronously enter or exit the optical path with the fourth wavelength selection module. The fifth half-wave plate is used to change the polarization state of the second-harmonic laser, so that the second-harmonic laser after the polarization state change and the residual fundamental laser do not undergo third-harmonic conversion in the third-harmonic crystal.

9. The multi-wavelength laser output device according to claim 8, characterized in that, It also includes multiple beam absorbers, each positioned at a different location to absorb the blocked laser energy: A first beam absorber is disposed above the first polarizer and is used to absorb the polarization component of the fundamental frequency laser that is blocked by the first polarizer. The second beam absorber is disposed above the second polarizer and is used to absorb the polarization component of the second-harmonic laser that is blocked by the second polarizer. The third beam absorber is disposed above the third polarizer and is used to absorb the polarization component of the third harmonic laser that is blocked by the third polarizer. A fourth beam absorber is disposed above the fourth polarizer and is used to absorb the polarization component of the fourth-harmonic laser that is blocked by the fourth polarizer. The fifth beam absorber is located at the end of the incident light path and is used to absorb the residual fundamental frequency laser and the second harmonic laser.

10. The multi-wavelength laser output device according to claim 9, characterized in that, It also includes a sixth half-wave plate and an output window plate; The sixth half-wave plate is disposed in the optical path between the laser source and the first 45° reflector, and is used to adjust the polarization direction of the fundamental frequency laser to vertical polarization and enter the subsequent optical path; The output window is located at the end of the outgoing optical path to seal the optical path system and allow laser output.

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