Device and method for adjusting resonant cavity mirror of straight cavity type solid laser

Abstract

The invention discloses a straight cavity type solid laser resonant cavity mirror assembling and adjusting device and method, belongs to the technical field of laser resonant cavity assembling and adjusting, and solves the problem that an existing solid laser resonant cavity mirror is low in assembling and adjusting precision. The device specifically comprises a short coherent light source which is connected with a coupler through an optical fiber; an output port of the coupler is connected with a measuring arm and a reference arm through two paths of optical fibers respectively; a combined output port of the coupler is connected with a photodiode through an optical fiber, and the photodiode is connected with a control unit. According to the method, the actual cavity length of the straight cavity type solid laser resonant cavity is accurately measured by adopting a short coherence interference measurement technology, then the parameter indexes of the cavity length are designed according to the solid laser resonant cavity designed in the earlier stage, an accurate assembly error value is obtained, then the cavity mirror of the resonant cavity is accurately assembled and adjusted, and the assembly and adjustment precision is high.

Description

Technical Field

[0001] The present invention relates to the technical field of laser resonator alignment, and particularly to a cavity mirror alignment device and alignment method for a straight-cavity solid laser resonator. Background Art

[0002] Solid-state lasers are a type of lasers that use solid laser materials as the working medium. Due to their advantages such as high output power, good beam quality, high conversion efficiency, and good pulse characteristics, they are widely used in fields such as medical treatment, communication, industry, and national defense. As the core component of a solid-state laser, the structure of the resonator not only determines the beam quality and output power of the laser, but also affects laser parameters such as the spectral characteristics and pulse characteristics of the laser. The definition of the resonator length is the equivalent optical path length between two mirrors, and its actual value is affected by various factors such as mechanical assembly errors, thermal deformation, and vibration interference. Existing research shows that when the cavity length offset exceeds a specific threshold, the output characteristics of the laser will deteriorate observably. Therefore, accurately aligning the cavity mirrors of the resonator and thus precisely controlling the cavity length of the resonator is of great significance for ensuring the stability of the laser output characteristics.

[0003] In a Chinese invention patent with the authorization announcement number CN109633921B, a laser cavity mirror auxiliary alignment device and its usage method are disclosed. In the laser cavity mirror auxiliary alignment method of this patent, with an adjustable-focus visible laser as the reference light source, the center position of the reflected light spot on the observation screen is located by using an optical field camera, and the laser cavity mirror is clamped by a mirror frame robotic arm for alignment, achieving precise alignment of the laser cavity mirror. However, the high precision of this device depends on the performance and cooperation of each component, and during long-term use, it may affect the alignment accuracy and stability.

[0004] In a Chinese utility model patent with the authorization announcement number CN219458293U, a solid-state laser resonator assembly alignment device is disclosed. In the solid-state laser resonator assembly alignment device of this patent, a positioning reference is formed by a positioning support and a positioning bracket, and a pneumatic grasping tooling is used to achieve rapid positioning and assembly of the laser rod and the xenon lamp. The parallelism of each end face of the resonator assembly is calibrated by means of equipment such as an internal focusing autocollimator parallel light tube, thereby achieving precise alignment of the solid-state laser resonator assembly. However, the equipment used has high requirements for the environment and operators, and the alignment efficiency and automation level are relatively low.

[0005] In a Chinese utility model patent with the authorization announcement number CN220692519U, an auxiliary alignment structure and an optical reflection cavity are disclosed. In the auxiliary alignment structure of this patent, the auxiliary mirror group has two working positions, namely collimation and light passing, which can receive the reflected light beam, and its angle and position can be flexibly adjusted, facilitating the collimation of the cavity mirror of the optical reflection cavity. The optical reflection cavity includes a cavity with adjustable vacuum degree, a cavity mirror, and this auxiliary alignment structure, and can efficiently and accurately align the cavity mirror in a vacuum environment. However, there are deficiencies such as complex structure resulting in high manufacturing and maintenance costs, and the applicable range being limited to specific optical reflection cavities.

[0006] In summary, there are problems in the alignment of the cavity mirror of the existing solid laser resonator, such as low accuracy, being greatly affected by environmental factors, and relying on manual operation. Therefore, the present invention proposes a cavity mirror alignment device and an alignment method for a straight-cavity solid laser resonator. Summary of the Invention

[0007] Aiming at the deficiencies existing in the prior art, the present invention provides a cavity mirror alignment device and an alignment method for a straight-cavity solid laser resonator, which solve the problem of low alignment accuracy of the cavity mirror of the existing solid laser resonator.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows: A cavity mirror alignment device for a straight-cavity solid laser resonator includes a short-coherence light source, and the short-coherence light source is connected with a coupler through an optical fiber; the output port of the coupler is respectively connected with a measurement arm and a reference arm through two optical fibers; the combined output port of the coupler is connected with a photodiode through an optical fiber, and the photodiode is connected with a control unit; The measurement arm includes a first adjustable collimator, and the input port of the first adjustable collimator is connected with the output port of the coupler through an optical fiber; an output mirror is arranged at the light output end of the first adjustable collimator, a total reflection mirror is arranged at the light transmission end of the output mirror, and the output mirror and the total reflection mirror are installed inside the cavity of the straight-cavity solid laser resonator; an electric control displacement stage is installed at the bottom of the total reflection mirror, and a three-dimensional adjustment frame is arranged at the bottom of the electric control displacement stage; the three-dimensional adjustment frame is arranged on the mounting frame assembly.

[0009] In this solution, a short-coherence light source emits a laser beam. The coupler splits the beam emitted by the short-coherence light source. One beam travels through an optical fiber to the measurement arm, and the other beam travels through an optical fiber to the reference arm. The beams reflected back from the measurement arm and the reference arm enter the coupler and are combined. After combination, the beam is transmitted through an optical fiber to a photodiode. The photodiode converts the combined beam into an electrical signal and transmits it to the control unit. The control unit controls the reference arm to perform a scanning measurement, thereby achieving high-precision measurement of the actual cavity length of the resonator cavity of a straight-cavity solid-state laser. Then, according to the parameter indicators of the designed cavity length of the solid-state laser resonator cavity in the early stage, an accurate assembly error value is obtained, and then the cavity mirrors of the resonator cavity are precisely adjusted. The adjustment accuracy can reach the micron level.

[0010] Further, the mounting frame assembly includes an optical air-bearing platform. A base is installed on the optical air-bearing platform, and a column is provided on the base. The three-dimensional adjustment frame is supported on the column. A support rod is installed on the optical air-bearing platform. A resonator cavity gripper is provided on the support rod. The resonator cavity of the straight-cavity solid-state laser is fixed on the resonator cavity gripper. A cross bar is connected to the support rod, and a collimator adjustment frame is connected to the cross bar. The first adjustable collimator is installed on the collimator adjustment frame.

[0011] In this solution, the support rod is used to connect and support the cross bar and the resonator cavity gripper. The cross bar is used to connect the collimator adjustment frame and can be adjusted in height. The collimator adjustment frame can adjust the pitch angle of the first adjustable collimator. The resonator cavity gripper is used to grip and fix the resonator cavity. The column is used to support devices such as the three-dimensional adjustment frame and the electric control displacement stage. The base is used to fix the position of the column on the optical air-bearing platform and provide stability. The optical air-bearing platform provides stable support for the device and improves the overall system stability.

[0012] Further, the reference arm includes a second adjustable collimator. The input port of the second adjustable collimator is connected to the output port of the coupler through an optical fiber. A reference mirror is provided at the light output end of the second adjustable collimator.

[0013] In this solution, the reference mirror is the reflecting mirror of the optical path where the reference arm is located. It is installed on an automatic displacement stage including a linear scale delay line and is used to reflect the laser in the reference arm after passing through the delay line.

[0014] In a second aspect, based on the cavity mirror alignment device of a straight-cavity solid-state laser resonator provided in the first aspect, the present invention provides a method for aligning the cavity mirrors of a straight-cavity solid-state laser resonator, including the following steps: S1: The short-coherence light source emits a beam, and the beam is transmitted to the coupler through an optical fiber. S2: The coupler splits the beam into two paths. One path is transmitted to the measurement arm through an optical fiber, and the other path is transmitted to the reference arm through an optical fiber. S3: Adjust the measurement arm so that the two beams of light are reflected by the measurement arm and the reference arm respectively and then return to the coupler along the optical fiber. S4: The coupler combines the two beams of light and transmits them through the optical fiber to the photodiode. The photodiode converts the optical signal into an electrical signal and transmits it to the control unit. S5: The control unit controls the reference mirror in the reference arm to perform a scanning measurement, obtains the envelope information of the interference signal of the two beams of light, and then determines the actual cavity length of the straight-cavity solid-state laser resonator; and then performs alignment according to the error between the actual cavity length of the straight-cavity solid-state laser resonator and the designed cavity length of the straight-cavity solid-state laser resonator.

[0015] In this solution, the short-coherence interference measurement technology is used to accurately measure the measured value of the actual cavity length of the straight-cavity solid-state laser resonator. After obtaining the measured value of the actual cavity length of the straight-cavity solid-state laser resonator, according to the parameter index of the designed cavity length of the straight-cavity solid-state laser resonator designed in the early stage, an accurate assembly error value is obtained, and the cavity mirror is accurately aligned according to the error value, with high alignment accuracy and less influence by environmental factors.

[0016] Further, in S1, the beam emitted by the short-coherence light source includes two parts. One part is the test light with a central wavelength of 1310 nm, and the other part is the red visible debugging light with a wavelength of 655 nm. The two beams of light are output in a common path.

[0017] In this solution, part of the red visible debugging light is convenient for observing the beam path when adjusting each optical component.

[0018] Further, S3 includes: S301: Adjust the first adjustable collimator and the three-dimensional adjustment frame so that the outgoing beam of the first adjustable collimator is perpendicularly incident on the three-dimensional adjustment frame. S302: Install the cavity body of the straight-cavity solid-state laser resonator and make the cavity body of the straight-cavity solid-state laser resonator perpendicular to the optical air-bearing platform. S303: Assemble the output mirror so that the outgoing beam of the first adjustable collimator is perpendicularly incident on the center of the output mirror; adjust the angle of the output mirror so that the reflected beam of the output mirror enters the light outlet of the first adjustable collimator. S304: Place the electric displacement stage on the three-dimensional adjustment frame and place the total reflection mirror on the electric displacement stage; adjust the three-dimensional adjustment frame so that the reflected beam of the total reflection mirror returns to the light outlet of the first adjustable collimator along the path of the original incident beam. S305: The reflected beam of the output mirror and the reflected beam of the total reflection mirror return to the coupler after passing through the first adjustable collimator.

[0019] Further, when adjusting the first adjustable collimator and the three-dimensional adjustment frame in S301, place a plane mirror on the three-dimensional adjustment frame, and adjust the angles of the first adjustable collimator and the three-dimensional adjustment frame until the red visible debugging light is observed to be reflected back to the light outlet of the first adjustable collimator.

[0020] Further, S5 includes: S501: Input measurement parameters in the control unit and start scanning measurement; the measurement parameters include the laser gain emitted by the first adjustable collimator, the optical material of the output mirror, and the initial position of the reference arm delay line scan; S502: The control unit controls the reference mirror in the reference arm to perform scanning measurement. After the scanning measurement, two envelope peaks corresponding to the light reflected by the reflection surface of the output mirror close to the cavity and the light reflected by the total reflection mirror are displayed in the control unit. The peak positions of the two envelope peaks are x 1 and x 2 , x 1 and x 2 correspond to the positions of the reflection surface of the output mirror and the total reflection mirror respectively; according to the position difference between x 1 and x 2 , obtain the distance between the reflection surface of the output mirror close to the cavity and the total reflection mirror, that is, the actual cavity length of the straight-cavity solid-state laser resonator; S503: Compare the actual cavity length of the straight-cavity solid-state laser resonator measured with the designed cavity length of the straight-cavity solid-state laser resonator to obtain the relative error of the distance between the output mirror and the total reflection mirror. Determine the moving direction and distance of the total reflection mirror according to this relative error, and use an electric control displacement stage to move the total reflection mirror at the micron level; S504: Repeat S501~S503, measure the actual cavity length of the straight-cavity solid-state laser resonator multiple times and adjust the position of the total reflection mirror until the distance between the output mirror and the total reflection mirror meets the designed cavity length of the straight-cavity solid-state laser resonator; fix the total reflection mirror, and the alignment of the cavity mirrors of the straight-cavity solid-state laser resonator is completed.

[0021] The beneficial effects of the present invention are: In the method for aligning cavity mirrors of a straight-cavity solid-state laser resonator provided by the present invention, the short-coherence interference measurement technology is used to accurately measure the cavity length of the straight-cavity solid-state laser resonator; the coherence length of the short-coherence light source is relatively short, generally in the order of microns to hundreds of microns. Only when the optical path difference between the two beams of light is close to zero will obvious interference fringes be generated. By extracting the envelope information of the interference signal, the high-precision measurement of the cavity length of the straight-cavity solid-state laser resonator is realized. Then, combined with an electric control displacement stage and a three-dimensional adjustment frame, the cavity mirrors of the resonator are accurately aligned. After alignment, the accuracy of the actual cavity length of the straight-cavity solid-state laser resonator compared with the designed cavity length can reach the micron level, and the alignment accuracy is high.

[0022] The overall structure of the cavity mirror alignment device for the straight cavity solid laser provided by the present invention is simple, with a high degree of automation, and is suitable for the high-precision alignment of the cavity mirrors of a straight cavity solid laser without an adjustment structure; the measuring arm adopts a vertical structure, with a reliable and stable overall structure, which is convenient for the operators to perform alignment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. is a schematic structural diagram of a cavity mirror alignment device for a straight cavity solid laser according to the present invention; Figure 2 FIG. is a schematic structural diagram of the measuring arm of the present invention; Figure 3 FIG. is a schematic structural diagram when the reflected light beam of the total reflection mirror in the measuring arm of the present invention cannot enter the light output port of the first adjustable collimator; Figure 4 FIG. is a schematic diagram of the short coherence interference simulated interference fringes of the present invention; Figure 5 FIG. is an interference envelope information diagram of measuring the cavity length of a straight cavity solid laser resonator by short coherence interference of the present invention.

[0024] REFERENCE SIGNS: 1. Short coherence light source; 2. Coupler; 3. Measuring arm; 4. Reference arm; 5. Photodiode; 6. Control unit; 7. First adjustable collimator; 8. Straight cavity solid laser resonator cavity body; 9. Output mirror; 10. Total reflection mirror; 11. Electrically controlled displacement stage; 12. Three-dimensional adjustment frame; 13. Reference mirror; 14. Collimator adjustment frame; 15. Cross bar; 16. Support rod; 17. Resonator holder; 18. Column; 19. Base; 20. Optical air-bearing platform; 21. Second adjustable collimator. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The following describes the specific embodiments of the present invention to facilitate those skilled in the art to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are within the scope of protection.

[0026] Embodiment 1 As Figure 1 shown, this embodiment provides a cavity mirror alignment device for a straight cavity solid laser. The cavity mirror alignment device for the straight cavity solid laser uses short coherence interference measurement technology to accurately measure the actual cavity length of the straight cavity solid laser resonator, and is equipped with an electrically controlled displacement stage 11 and a three-dimensional adjustment frame 12 for high-precision alignment of the cavity mirrors; specifically, it includes: Short coherence light source 1, coupler 2, measurement arm 3, reference arm 4, photodiode 5, control unit 6 and mounting frame assembly; Among them, the short coherence light source 1 is connected to the coupler 2 through an optical fiber; the output port of the coupler 2 is respectively connected to the measurement arm 3 and the reference arm 4 through two optical fibers; the measurement arm 3 is fixed on the mounting frame assembly; the short coherence light source 1 emits a laser beam, and the coupler 2 splits the beam emitted by the short coherence light source 1. One beam goes to the measurement arm 3 through an optical fiber, and the other beam goes to the reference arm 4 through an optical fiber. The combined output port of the coupler 2 is connected to the photodiode 5 through an optical fiber, and the photodiode 5 is connected to the control unit 6; the beams reflected back by the measurement arm 3 and the reference arm 4 enter the coupler 2 to be combined, and after combination, they are transmitted to the photodiode 5 through an optical fiber. The photodiode 5 converts the combined beam into an electrical signal and transmits it to the control unit 6.

[0027] As Figure 2 shown, the measurement arm 3 includes a first adjustable collimator 7, a straight cavity solid laser resonator cavity 8, an output mirror 9, a total reflection mirror 10, an electric control displacement stage 11 and a three-dimensional adjustment frame 12; The input port of the first adjustable collimator 7 is connected to the output port of the coupler 2 through an optical fiber, and the adjustable collimator converts the beam transmitted from the coupler 2 into a collimated laser beam; an output mirror 9 is arranged at the light output end of the first adjustable collimator 7, and a total reflection mirror 10 is arranged at the light transmission end of the output mirror 9. The output mirror 9 and the total reflection mirror 10 are installed inside the straight cavity solid laser resonator cavity 8; the total reflection mirror 10 is installed with an electric control displacement stage 11 at the bottom, and the electric control displacement stage 11 can drive the total reflection mirror 10 to achieve micron-level displacement; a three-dimensional adjustment frame 12 is arranged at the bottom of the electric control displacement stage 11, and the three-dimensional adjustment frame 12 can achieve all-round adjustment of the total reflection mirror 10 in the horizontal direction and the pitching direction; the three-dimensional adjustment frame 12 is arranged on the mounting frame assembly.

[0028] The mounting frame assembly includes an optical air-bearing platform 20, a base 19, a column 18, a support rod 16, a resonator holder 17, a cross bar 15 and a collimator adjustment frame 14; The optical air-bearing platform 20 is installed with the base 19, the base 19 is provided with a column 18, and the three-dimensional adjustment frame 12 is supported on the column 18; the optical air-bearing platform 20 is installed with a support rod 16, the support rod 16 is provided with a resonator holder 17, and the straight cavity solid laser resonator cavity 8 is fixed on the resonator holder 17; a cross bar 15 is connected to the support rod 16, a collimator adjustment frame 14 is connected to the cross bar 15, the first adjustable collimator 7 is installed on the collimator adjustment frame 14, and the collimator adjustment frame 14 can adjust the pitching angle of the first adjustable collimator 7.

[0029] The reference arm 4 includes a second adjustable collimator 21 and a reference mirror 13; the input port of the second adjustable collimator 21 is connected to the output port of the coupler 2 through an optical fiber; a reference mirror 13 is provided at the optical output end of the second adjustable collimator 21; the reference mirror 13 is the reflecting mirror of the optical path where the reference arm 4 is located and is installed on an automatic displacement stage including a linear scale delay line for reflecting the laser beam after passing through the delay line in the reference arm 4.

[0030] Embodiment 2 Based on the collimator alignment device for the cavity mirrors of a straight-cavity solid-state laser resonator provided in Embodiment 1, this embodiment provides a method for aligning the cavity mirrors of a straight-cavity solid-state laser resonator, including the following steps: S1: The short coherence light source 1 emits a light beam, and the light beam is transmitted to the coupler 2 through an optical fiber; The light beam emitted by the short coherence light source 1 includes two parts. One part is the test light with a central wavelength of 1310 nm, and the other part is the red visible debugging light with a wavelength of 655 nm. The two light beams are output in a common path; the red visible debugging light is convenient for observing the light beam path when adjusting each optical component.

[0031] S2: The coupler 2 splits the light beam into two paths. One path is transmitted to the measurement arm 3 through an optical fiber, and the other path is transmitted to the reference arm 4 through an optical fiber.

[0032] S3: Adjust the measurement arm 3 so that the two light beams are reflected by the measurement arm 3 and the reference arm 4 respectively and then return to the coupler 2 along the optical fiber; specifically including: S301: Adjust the first adjustable collimator 7 and the three-dimensional adjustment frame 12 so that the outgoing light beam of the first adjustable collimator 7 is vertically incident on the three-dimensional adjustment frame 12; when adjusting, place a plane mirror on the three-dimensional adjustment frame 12 and adjust the angles of the first adjustable collimator 7 and the three-dimensional adjustment frame 12 until it is observed that the red visible debugging light is reflected back to the light output port of the first adjustable collimator 7; S302: Install the cavity body 8 of the straight-cavity solid-state laser resonator and make the cavity body 8 of the straight-cavity solid-state laser resonator perpendicular to the optical air-bearing platform 20; S303: Assemble the output mirror 9 so that the outgoing light beam of the first adjustable collimator 7 is vertically incident on the exact center of the output mirror 9; adjust the angle of the output mirror 9 so that the reflected light beam of the output mirror 9 enters the light output port of the first adjustable collimator 7; S304: Place the electric control displacement stage 11 on the three-dimensional adjustment frame 12 and place the total reflection mirror 10 on the electric control displacement stage 11; adjust the three-dimensional adjustment frame 12 so that the reflected light beam of the total reflection mirror 10 returns to the light output port of the first adjustable collimator 7 along the original incident light beam path; if the direction and angle of the three-dimensional adjustment frame 12 cannot be adjusted properly, the reflected light beam of the total reflection mirror 10 cannot enter the light output port of the first adjustable collimator 7, as Figure 3 shown; In this step, when assembling the total reflection mirror 10, the actual cavity length of the straight-cavity solid-state laser resonator is made approximately equal to the designed cavity length of the straight-cavity solid-state laser resonator, reducing the subsequent alignment and adjustment workload. S305: The reflected light beam of the output mirror 9 and the reflected light beam of the total reflection mirror 10 return to the coupler 2 after passing through the first adjustable collimator 7.

[0033] S4: The coupler 2 combines the two light beams into one and transmits them through an optical fiber to the photodiode 5. The photodiode 5 converts the optical signal into an electrical signal and transmits it to the control unit 6. S5: The control unit 6 controls the reference mirror 13 in the reference arm 4 to perform a scanning measurement to obtain the envelope information of the interference signal of the two light beams, and then determines the actual cavity length of the straight-cavity solid-state laser resonator; and then performs alignment and adjustment according to the error between the actual cavity length of the straight-cavity solid-state laser resonator and the designed cavity length of the straight-cavity solid-state laser resonator. Specifically, it includes: S501: Input measurement parameters in the control unit 6; where the measurement parameters include the laser gain at the output of the first adjustable collimator, the optical material of the output mirror, the initial position of the reference arm delay line scan, etc. S502: The control unit 6 controls the reference mirror 13 in the reference arm 4 to perform a scanning measurement. After the scanning measurement, two envelope peaks corresponding to the light reflected by the reflection surface of the output mirror 9 close to the cavity and the light reflected by the total reflection mirror 10 are displayed in the control unit 6. According to the knowledge of physical optics, the coherence length of a Gaussian light source can be expressed as:

[0034] where, is the central wavelength of the test light, is the spectral width, ln is the natural logarithm with the natural number e as the base; π is the pi; In this embodiment, the central wavelength of the test light is 1310 nm, and the spectral width is 30 nm, and the coherence length is obtained as 25.24 μm; Taking the zero position of the reference mirror 13 as the center, the position corresponding to the zero of the group delay difference, that is, the position where the optical path differences of the two optical paths are equal at the peak position of the envelope peak, as Figure 4 shown; Define the light reflected by the reflection surface of the output mirror 9 close to the cavity as R1, and the light returned by the total reflection mirror 10 as R2. The peak positions of the envelopes of the light R1 reflected by the reflection surface of the output mirror 9 close to the cavity and the light R2 reflected by the total reflection mirror 10 are x 1 and x 2 , x 1 and x 2 correspond to the positions of the reflection surface of the output mirror 9 and the total reflection mirror 10 respectively; According to x1 and x 2 The position difference with x gives the distance between the output mirror 9 and the reflecting surface inside the cavity and the total reflection mirror 10, that is, the actual cavity length of the resonant cavity of the straight-cavity solid laser; S503: Compare the actual cavity length of the resonant cavity of the straight-cavity solid laser measured with the designed cavity length of the resonant cavity of the straight-cavity solid laser to obtain the relative error of the distance between the output mirror 9 and the total reflection mirror 10. Determine the moving direction and distance of the total reflection mirror 10 according to this relative error, and use the electric control displacement stage 11 to precisely move the total reflection mirror 10 at the micron level; S504: Repeat the execution of S501~S503, measure the actual cavity length of the resonant cavity of the straight-cavity solid laser multiple times and adjust the position of the total reflection mirror 10 until the distance between the output mirror 9 and the total reflection mirror 10 meets the designed cavity length of the resonant cavity of the straight-cavity solid laser; fix the total reflection mirror 10, and the alignment of the cavity mirrors of the resonant cavity of the straight-cavity solid laser is completed.

[0035] Those of ordinary skill in the art will realize that the embodiments here are to help the reader understand the principles of the present invention, and it should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific deformations and combinations without departing from the essence of the present invention according to the technical revelations disclosed in the present invention, and these deformations and combinations are still within the protection scope of the invention.

Claims

1. A device for adjusting the resonant cavity mirror of a straight cavity solid laser, characterized in that: The invention comprises a short coherent light source (1), wherein the short coherent light source (1) is connected to a coupler (2) via an optical fiber; an output port of the coupler (2) is respectively connected to a measuring arm (3) and a reference arm (4) via two optical fibers; a combined output port of the coupler (2) is connected to a photodiode (5) via an optical fiber, and the photodiode (5) is connected to a control unit (6); The measuring arm (3) comprises a first adjustable collimator (7), the input port of the first adjustable collimator (7) being connected to the output port of the coupler (2) via an optical fiber; an output mirror (9) is provided at the light output end of the first adjustable collimator (7), a total reflection mirror (10) is provided at the light transmission end of the output mirror (9), and both the output mirror (9) and the total reflection mirror (10) are mounted inside a resonant cavity (8) of a straight-cavity solid-state laser; an electrically controlled displacement stage (11) is mounted at the bottom of the total reflection mirror (10), and a three-dimensional adjustment frame (12) is provided at the bottom of the electrically controlled displacement stage (11); the three-dimensional adjustment frame (12) is arranged on a mounting frame assembly.

2. The device for adjusting the resonant cavity mirror of a straight cavity solid-state laser according to claim 1, characterized in that: The mounting frame assembly comprises an optical air floating platform (20), a base (19) is mounted on the optical air floating platform (20), a column (18) is arranged on the base (19), and the three-dimensional adjustment frame (12) is supported on the column (18); A support rod (16) is installed on the optical air floating platform (20), a resonant cavity holder (17) is arranged on the support rod (16), and the resonant cavity body (8) of the straight cavity solid laser is fixed on the resonant cavity holder (17); a cross bar (15) is connected to the support rod (16), a collimator adjustment frame (14) is connected to the cross bar (15), and the first adjustable collimator (7) is installed on the collimator adjustment frame (14).

3. The device for adjusting the resonant cavity mirror of a straight cavity solid laser according to claim 1, characterized in that: The reference arm (4) comprises a second adjustable collimator (21), the input port of the second adjustable collimator (21) being connected to the output port of the coupler (2) via an optical fiber; and a reference mirror (13) is provided at the light output end of the second adjustable collimator (21).

4. A method for adjusting a mirror of a straight-cavity solid-state laser resonator according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1: A short coherent light source (1) emits a light beam, which is transmitted to a coupler (2) via an optical fiber; S2: The coupler (2) splits the light beam into two paths, one of which is transmitted to the measurement arm (3) through the optical fiber, and the other is transmitted to the reference arm (4) through the optical fiber; S3: adjusting the measuring arm (3) so that the two light beams are respectively reflected by the measuring arm (3) and the reference arm (4) and then return to the coupler (2) along the optical fiber; S4: The coupler (2) combines the two light beams and transmits them to the photodiode (5) through the optical fiber. The photodiode (5) converts the optical signal into an electrical signal and transmits it to the control unit (6); S5: the control unit (6) controls the reference mirror (13) in the reference arm (4) to perform scanning measurement, thereby obtaining envelope information of the interference signal of the two light beams, and further determining the actual cavity length of the resonant cavity of the straight cavity solid-state laser; Then, adjustment is performed according to the error between the actual cavity length of the straight-cavity solid-state laser resonant cavity and the designed cavity length of the straight-cavity solid-state laser resonant cavity.

5. The method for adjusting the mirror of a straight cavity solid-state laser resonator according to claim 4, characterized in that: In S1, the light beam emitted by the short coherent light source (1) comprises two parts, one part is a test light with a central wavelength of 1310 nm, and the other part is a red visible debugging light with a wavelength of 655 nm, and the two light beams are output on a common path.

6. The method for adjusting the mirror of a straight cavity solid-state laser resonator according to claim 5, characterized in that: The S3 includes: S301: adjusting the first adjustable collimator (7) and the three-dimensional adjustment frame (12) so that the outgoing light beam of the first adjustable collimator (7) is vertically irradiated on the three-dimensional adjustment frame (12); S302: installing a straight-cavity solid-state laser resonant cavity (8), and making the straight-cavity solid-state laser resonant cavity (8) perpendicular to the optical air-floating platform (20); S303: Assembling the output mirror (9) so that the output light beam of the first adjustable collimator (7) is vertically incident on the exact center of the output mirror (9); adjusting the angle of the output mirror (9) so that the reflected light beam of the output mirror (9) enters the light outlet of the first adjustable collimator (7); S304: placing an electrically controlled displacement stage (11) on a three-dimensional adjustment frame (12), and placing a total reflection mirror (10) on the electrically controlled displacement stage (11); adjusting the three-dimensional adjustment frame (12) so that the reflected light beam of the total reflection mirror (10) returns to the light outlet of the first adjustable collimator (7) along the path of the original incident light beam; S305: The reflected light beam of the output mirror (9) and the reflected light beam of the total reflection mirror (10) pass through the first adjustable collimator (7) and then return to the coupler (2).

7. The method for adjusting the mirror of a straight cavity solid-state laser resonator according to claim 6, characterized in that: When adjusting the first adjustable collimator (7) and the three-dimensional adjustment frame (12) in S301, a plane reflector is placed on the three-dimensional adjustment frame (12), and the angles of the first adjustable collimator (7) and the three-dimensional adjustment frame (12) are adjusted until red visible adjustment light is observed to be reflected back to the light outlet of the first adjustable collimator (7).

8. The method for adjusting the mirror of a straight cavity solid-state laser resonator according to claim 6, characterized in that: The S5 includes: S501: inputting measurement parameters into the control unit (6); wherein the measurement parameters include the output laser gain of the first adjustable collimator, the optical material of the output mirror, and the initial scanning position of the reference arm delay line; S502: the control unit (6) controls the reference mirror (13) in the reference arm (4) to perform scanning measurement. After the scanning measurement, two envelope peaks corresponding to the light reflected by the reflection surface of the output mirror (9) close to the cavity and the light reflected by the total reflection mirror (10) are displayed on the control unit (6). The positions of the two envelope peaks are x1 and x2, respectively. x1 and x2 correspond to the positions of the reflection surface of the output mirror (9) and the total reflection mirror (10), respectively. According to the position difference between x1 and x2, the distance between the reflection surface of the output mirror (9) close to the cavity and the total reflection mirror (10) is obtained, that is, the actual cavity length of the resonant cavity of the straight cavity solid-state laser. S503: comparing the measured actual cavity length of the straight cavity solid laser resonator with the designed cavity length of the straight cavity solid laser resonator to obtain a relative error of the distance between the output mirror (9) and the total reflection mirror (10), determining the moving direction and distance of the total reflection mirror (10) based on the relative error, and using an electric-controlled displacement stage (11) to move the total reflection mirror (10) in micrometer level; S504: Repeat S501 to S503, measure the actual cavity length of the straight-cavity solid-state laser resonant cavity multiple times and adjust the position of the total reflection mirror (10) until the distance between the output mirror (9) and the total reflection mirror (10) meets the designed cavity length of the straight-cavity solid-state laser resonant cavity; fix the total reflection mirror (10), and the cavity mirror adjustment of the straight-cavity solid-state laser resonant cavity is completed.

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