Device and method for detecting laser thermal lens effect of optical crystal

Abstract

The invention discloses an optical crystal laser thermal lens effect detection device and method, and relates to the field of thermal lens effect detection.The optical crystal laser thermal lens effect detection device comprises a pump laser, a red light detection laser and a power detector, and a beam combiner, a crystal sample table and a beam splitter are sequentially arranged in the light beam direction of the pump laser; a front reflecting mirror is arranged in the light beam direction of the detection red light laser and is used for reflecting the light beam of the detection red light laser towards the beam combiner, so that the light beam of the detection red light laser and the light beam of the pump laser coincide and penetrate through the optical crystal, and a rear reflecting mirror is arranged corresponding to the power detector; the pumping laser and the probe light coincide and penetrate through the optical crystal, the optical crystal is heated through the pumping laser, the thermal lens effect of the optical crystal is induced to be amplified, then the probe light is detected, the strength of the thermal lens effect of the optical crystal can be clearly judged, and grading of crystal quality and improvement of a production process are facilitated.

Description

Technical Field

[0001] The invention relates to the field of thermal lens effect detection, and in particular to a detection device and method for optical crystal laser thermal lens effect. Background Art

[0002] The laser thermal lens effect of optical crystals is due to the absorption of laser by the crystal itself, which causes uneven distribution inside the crystal, resulting in reduced beam quality, unstable laser output power, etc. Detecting the thermal lens effect of optical crystals can help crystal manufacturers evaluate the light absorption characteristics of the crystals, which is beneficial to the grading of crystal quality and the improvement of production processes.

[0003] There are many existing methods for detecting the thermal lens effect of crystal lasers. Basically, the laser beam is directly applied to the optical crystal. The intensity of the lens effect is low, resulting in unclear detection data and a lack of induction of the intensity of the thermal lens effect. Summary of the invention

[0004] In order to make up for the deficiencies of the existing technical problems, the purpose of the present invention is to provide a detection device and method for the thermal lens effect of optical crystal lasers, which is used to solve the problem that the existing detection method of the crystal thermal lens effect lacks the induction of the intensity of the thermal lens effect, resulting in the feedback detection data being not obvious enough.

[0005] In order to solve the problems of the prior art, the technical solution of the present invention is as follows: The invention discloses a detection device for thermal lens effect of optical crystal laser, comprising: a pump laser, a detection red light laser and a power detector. A beam combiner, a crystal sample stage and a beam splitter are arranged in sequence along the beam direction of the pump laser. The crystal sample stage is used to position the optical crystal. A front reflector is arranged in the beam direction of the detection red light laser. The front reflector is used to reflect the beam of the detection red light laser toward the direction of the beam combiner so that the beam of the detection red light laser overlaps with the beam of the pump laser and passes through the optical crystal. A rear reflector is arranged corresponding to the power detector. The beam of the detection red light laser is guided to the power detector after being reflected by the beam splitter and the rear reflector in sequence.

[0006] Preferably, a beam trash can is provided corresponding to the beam splitter, and the light beam of the pump laser passes through the beam splitter and is guided to the beam trash can.

[0007] Preferably, it also includes an angle adjuster, which includes an integrated box. Four groups of belt assemblies are arranged in the integrated box. The front reflector, beam combining mirror, beam splitter and rear reflector are all connected to the belt assemblies through belts. A drive rod is inserted and pulled along the arrangement direction of the belt assemblies in the integrated box. The insertion and pulling displacement of the drive rod can engage with one of the four groups of belt assemblies. The rotating drive rod can select one of the transmission and adjustment angles of the reflector, beam combining mirror, beam splitter and rear reflector.

[0008] Preferably, the belt assembly includes a driving pulley, and the front reflector, beam combining mirror, beam splitter, and rear reflector are all rotatably mounted on the surface of the bracket via a damping bearing, and the reflector, beam combining mirror, beam splitter, and rear reflector are all coaxially fixed with a driven pulley, and the driven pulley is connected to the driving pulley via a belt transmission, and the driving pulley is coaxially fixed with a driven gear, and the driven gear is meshedly connected to the driving gear, and the driving rod can be meshedly connected to one of the driving gears.

[0009] Preferably, a tensioning wheel is arranged opposite to the driving pulley, and the belt on the outer side of the driving pulley passes around the tensioning wheel. The tensioning wheel is swingably connected to the integrated box through a swing frame. A stud is rotatably connected to the surface of the swing frame. The surface of the integrated box has a through opening, and the stud passes through the through opening to the outside of the integrated box. A nut is threadedly connected to the surface of the stud, and the nut contacts the outer wall of the integrated box to pull the swing frame outward, so that the tensioning wheel tightens the belt.

[0010] Preferably, the driving rod includes a rod body, and the surface of the integrated box has a shaft tube, the rod body is linearly slidably inserted into the integrated box by the shaft tube, and a plurality of pressure plates are rotatably arranged around the outer end of the rod body, and the inner edge of the pressure plate is inclined toward the inner end of the rod body, and a plurality of fins are elastically rotatably arranged around the inner end of the rod body by a torsion spring, and the inner edge of the fin is inclined toward the outer end of the rod body, and an axle rod is axially slidably arranged inside the rod body, and the axle rod is connected to a spring that applies pressure to the outer end of the rod, and the two ends of the axle rod are respectively fixed with a rear sphere and a front sphere, the rear sphere contacts the inner edge of the pressure plate, and the front sphere contacts the inner edge of the fin, and the pressure plate is pressed to contact the rear sphere and the front sphere moves, so that the front sphere squeezes the fin to rotate and protrude out of the surface of the rod body.

[0011] Preferably, a plurality of tooth plates are elastically rotated in the integrated box by a torsion spring, and the tooth plates span the driving rod and engage with the driving gears one by one. The fins protrude from the surface of the rod body and engage with the driving gears, while the fins push the tooth plates to rotate and disengage from the driving gears.

[0012] Preferably, the portion where the tooth plate is engaged with the driving gear is an arc-shaped tooth surface, and the portion where the tooth plate crosses the driving rod is a smooth plate surface.

[0013] Preferably, the inner wall of the shaft tube is provided with a telescopic groove, in which a ball slides elastically through a spring, and a plurality of annular grooves are arranged on the surface of the rod body, in which the ball can be inserted, and the spacing of the annular grooves is the same as the spacing of the belt assembly.

[0014] A method for detecting an optical crystal laser thermal lens effect based on the optical crystal laser thermal lens effect detection device comprises the following specific steps: A. Beam debugging: Turn on the pump laser and the detection red laser. The pump laser beam passes through the beam combiner, optical crystal, and beam splitter in sequence. The detection red laser beam passes through the front reflector and beam combiner and passes through the optical crystal. Then, it passes through the beam splitter and rear reflector and is reflected to the power detector. Coordinate the reflection angles of the front reflector, beam combiner, beam splitter, and rear reflector to make the pump laser and detection red laser beams overlap and pass through the optical crystal, and ensure that the detection red laser beam is accurately guided to the power detector. B. Background noise collection: turn off the detection red laser, turn on the pump laser, and increase the beam power of the pump laser in sequence to obtain the background noise of the power detector; C. Variable power signal acquisition: Turn on the pump laser and the detection red laser. The pump laser beam heats the optical crystal. After the detection red laser beam passes through the optical crystal, the central light intensity of the diffraction spot is detected by a power detector. Then the pump laser beam power is increased in a gradient manner. The detection red laser beam is detected multiple times to obtain a trend line of the central light intensity of the diffraction spot changing with the pump power. The slope of the trend line is used to feedback the intensity of the thermal lens effect of the optical crystal.

[0015] Compared with the prior art, the advantages of the present invention are as follows: 1. The present invention overlaps the pump laser and the detection light and passes through the optical crystal. The pump laser heats the optical crystal, inducing the thermal lens effect of the optical crystal to be amplified. Then, the detection light is detected, and the strength of the thermal lens effect of the optical crystal can be clearly judged, which is beneficial to the grading of crystal quality and the improvement of production process.

[0016] 2. The present invention uses an angle adjuster to independently adjust the angles of the front reflector, beam combining mirror, beam splitter, and rear reflector at a fixed position, which is convenient for observing the beam overlap, easy to operate, and highly safe to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0018] Figure 2 This is a schematic diagram of the thermal lens effect measurement principle of the present invention.

[0019] Figure 3 It is a schematic diagram of the torsion transmission distribution of the lens of the present invention.

[0020] Figure 4 It is a schematic diagram of the structure of the angle adjuster of the present invention.

[0021] Figure 5 This is one of the structural schematic diagrams of the belt assembly of the present invention.

[0022] Figure 6 This is the second structural schematic diagram of the belt assembly of the present invention.

[0023] Figure 7 It is a schematic diagram of the driving rod structure of the present invention.

[0024] Figure 8 It is a schematic diagram of the limiting structure of the driving rod of the present invention.

[0025] Fig. 9 This is a trend diagram of the light intensity variation at the center of the diffraction spot of the present invention.

[0026] Figure numerals: 1. Pump laser; 2. Detection red laser; 3. Front reflector; 31. Beam combiner; 32. Beam splitter; 33. Rear reflector; 4. Power detector; 5. Beam trash can; 6. Crystal sample stage; 7. Angle adjuster; 71. Integrated box; 72. Driving pulley; 73. Driven gear; 74. Driving gear; 75. Tooth plate; 76. Tensioner; 77. Swing frame; 78. Stud; 79. Through port; 710. Shaft cylinder; 8. Driven pulley; 9. Drive rod; 91. Rod body; 92. Fin; 93. Pressure plate; 94. Shaft rod; 95. Rear sphere; 96. Front sphere; 97. Ring groove; 98. Ball; 99. Telescopic groove. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0028] like Figure 1 As shown, the detection device of the optical crystal laser thermal lens effect adopts a rectangular bracket as the basic support of the equipment, and a pump laser 1, a beam combiner 31, a crystal sample stage 6, a beam splitter 32, and a beam trash can 5 are installed in sequence along one side of the bracket in a straight line; Along the other side of the bracket, a detection red light laser 2, a front reflector 3, a rear reflector 33, and a power detector 4 are installed in sequence in a straight line; The beam trash can 5 adopts the existing water-cooled beam collector, the pump laser 1 adopts the existing 1064nm pump laser equipment, and the power detector 4 adopts a calorimetric power detector.

[0029] The detection method of optical crystal laser thermal lens effect is as follows: Beam debugging: fix the optical crystal to be tested by the crystal sample stage 6, turn on the pump laser 1 and the detection red laser 2, the beam of the pump laser 1 passes through the beam combiner 31, the optical crystal, and the beam splitter 32 in sequence, the beam of the detection red laser 2 passes through the front reflector 3 and the beam combiner 31 to pass through the optical crystal, and then passes through the beam splitter 32 and the rear reflector 33 to the power detector 4, coordinate and rotate the reflection angles of the front reflector 3, the beam combiner 31, the beam splitter 32, and the rear reflector 33, so that the beams of the pump laser 1 and the detection red laser 2 overlap and pass through the optical crystal, and ensure that the beam of the detection red laser 2 is accurately guided to the power detector 4; Background noise collection: turn off the detection red light laser 2, turn on the pump laser 1, detect the background noise entering the power detector 4, adjust the power of the pump laser 1 to collect the background noise multiple times, the pump laser power of the pump laser 1 is 0W, 50W, 100W, 150W, 200W respectively; Variable power signal acquisition: turn on the pump laser 1 and the detection red light laser 2. The light beam of the pump laser 1 passes through the beam combiner 31, the optical crystal, and the beam splitter 32 in sequence and is collected by the beam trash can 5. The pump laser beam of the pump laser 1 heats the optical crystal. The detection red light beam of the detection red light laser 2 coincides with the pump laser and passes through the optical crystal. The detection red light beam is reflected and guided to the power detector 4 through the beam splitter 32 and the rear reflector 33. The central light intensity of the diffraction spot of the detection red light beam is detected by the power detector 4. The pump laser power of the pump laser 1 is adjusted to 0W, 50W, 100W, 150W, and 200W respectively, and the light beam of the detection red light laser 2 is detected multiple times, so as to obtain a trend line of the central light intensity of the diffraction spot with the pump power. The slope of the trend line is used to feedback the intensity of the thermal lens effect of the optical crystal.

[0030] like Figure 2 As shown in the figure, the pump laser penetrates the optical crystal and generates a temperature rise gradient ∆T(r) in the cross-section r direction due to light absorption. The temperature rise is related to the light absorption A of the crystal. e It is closely related to the thermophysical parameters (density ρ, specific heat capacity c, thermal diffusivity D, thermal conductivity α), namely: ; The temperature rise gradient ∆T(r) causes a refractive index gradient inside the crystal: ; Refractive index gradient ∆ n ( r ) in the crystal length d The accumulation produces an optical path difference: ; The optical path difference δ(r) produces a phase difference in the probe laser beam: ; The phase difference generates a diffraction spot through the diffraction effect during the transmission of the detection laser beam, that is: ; The stronger the crystal's light absorption, the higher the temperature rise, the greater the refractive index gradient, the greater the phase difference, and the more obvious the diffraction spot.

[0031] like Fig. 9 As shown, “I r=0 -P e In the "trend line", the L0 line segment represents the pump laser background noise at different pump laser powers, the L1 line segment represents the central light intensity of the diffraction spot of the optical crystal measured at different pump laser powers, and the L2 line segment represents the actual measurement data of the optical crystal after deducting the background noise at different pump laser powers; Since the crystal temperature rise is highest at the center of the pump laser beam (r=0), the light intensity I at the center of the diffraction spot is taken as r=0 To evaluate the intensity of the crystal thermal lens effect, when the pump laser power increases linearly, I r=0 Approximately linear increase, for any optical crystal, we can get I r=0 With the pump laser power P e The trend line of change, that is, "I r=0 -P e Trend lines, such as Fig. 9 As shown, “I r=0 -P e The slope K of the "trend line" reflects the relative strength of the thermal lens effect of the optical crystal. The smaller the slope K, the smaller the thermal lens effect of the crystal and the better the crystal quality.

[0032] Keeping the beams of the pump laser 1 and the detection red laser 2 overlapped and running through the optical lens is the key to the detection process. In the above-mentioned beam debugging process, the front reflector 3, the beam combining mirror 31, the beam splitter 32, and the rear reflector 33 are rotated to overlap the beams and keep the beam of the detection red laser 2 accurately directed to the power detector 4. Since the beam of the pump laser 1 has a high temperature hazard, the equipment is densely distributed, and the overlap effect of the light needs to be observed at a suitable angle, it is extremely inconvenient to adjust the front reflector 3, the beam combining mirror 31, the beam splitter 32, and the rear reflector 33 one by one. The present application adopts an angle adjuster 7 that can independently adjust the angles of the front reflector 3, the beam combining mirror 31, the beam splitter 32, and the rear reflector 33 at a fixed observation position. The specific operation is as follows: like Figure 3-6As shown, the angle adjuster 7 is arranged between the front reflector 3 and the rear reflector 33, so as to facilitate the observation of the light beam overlap effect. The angle adjuster 7 includes an integrated box 71, in which four groups of belt assemblies are arranged, and the belt assembly includes a driving pulley 72. The front reflector 3, the beam combining mirror 31, the beam splitter 32, and the rear reflector 33 are all rotatably mounted on the surface of the bracket. The front reflector 3, the beam combining mirror 31, the beam splitter 32, and the rear reflector 33 are coaxially fixed with a driven pulley 8, and the driven pulley 8 is connected to each driving pulley 72 through a belt transmission. The belt between the driven pulley 8 and the driving pulley 72 limits the conduction path through a guide wheel to avoid winding contact between the belts. The driving pulley 72 is coaxially fixed with a driven gear 73, and a driving gear 74 is rotatably installed in the integrated box 71, and the driving gear 74 is meshed and connected with the driven gear 73. like Figure 7 As shown, the driving rod 9 is slidably inserted into one side of the integrated box 71, and the sliding direction of the driving rod 9 is parallel to the arrangement direction of the belt assembly. The driving rod 9 includes a rod body 91, and the surface of the integrated box 71 has a shaft tube 710. The rod body 91 is linearly slidably inserted into the integrated box 71 by the shaft tube 710. A plurality of pressure plates 93 are rotatably arranged around the outer end of the rod body 91, and the inner edge of the pressure plate 93 is inclined toward the inner end of the rod body 91. A plurality of fins 92 are elastically rotatably arranged around the inner end of the rod body 91 by a torsion spring, and the inner edge of the fin 92 is inclined toward the outer end of the rod body 91. A shaft rod 94 is axially slidably arranged inside the rod body 91, and the shaft rod 94 is connected to a spring for applying pressure to the outer end of the rod body 91. The two ends of the shaft rod 94 are respectively fixed with a rear sphere 95 and a front sphere 96, and the rear sphere 95 abuts against the inner edge of the pressure plate 93, and the front sphere 96 abuts against the inner edge of the fin 92. Under normal conditions, the fin 92 is retracted into the rod body 91. The outer end of the rod body 91 is held by hand, and the front end of the rod body 91 is aligned with the driving gear 74 by pulling and inserting the rod body 91. The pressure plate 93 is pressed by fingers to make the inner edge of the pressure plate 93 squeeze the rear sphere 95. The rear sphere 95 pushes the shaft 94 and the front sphere 96 to move as a whole, so that the front sphere 96 squeezes the fin 92 to overcome the elastic force and expand outward. The fin 92 is clamped with the driving gear 74. The rod body 91 is rotated to drive the driving gear 74 to rotate, so that the driven gear 73 drives the driving pulley 72 to rotate. The driven pulley 8 drives the front reflector 3 or the beam combiner 31 or the beam splitter 32 or the rear reflector 33 to rotate and adjust through the belt transmission, which is used to control the reflection direction of the light beam.

[0033] By controlling the alignment of the fins 92 with different driving gears 74 , the angles of the front reflector 3 , the beam combiner 31 , the beam splitter 32 , and the rear reflector 33 can be adjusted independently.

[0034] The front reflector 3, the beam combining mirror 31, the beam splitter 32 and the rear reflector 33 are all rotatably connected to the bracket through a damping bearing, so that the front reflector 3, the beam combining mirror 31, the beam splitter 32 and the rear reflector 33 have an autonomous positioning angle effect.

[0035] like Figure 5 , 6 As shown, a tensioning wheel 76 is arranged opposite to the driving pulley 72, and the belt on the outer side of the driving pulley 72 passes around the tensioning wheel 76. The tensioning wheel 76 is swingably connected to the integrated box 71 through a swing frame 77. A stud 78 is rotatably connected to the surface of the swing frame 77. The surface of the integrated box 71 has a through opening 79. The stud 78 passes through the through opening 79 to the outside of the integrated box 71. A nut is threadedly connected to the surface of the stud 78. The nut is rotated to contact the outer wall of the integrated box 71 to pull the swing frame 77 outward, so that the tensioning wheel 76 tightens the belt, keeping the belt able to transmit power to rotate the driven pulley 8 to adjust the angle.

[0036] like Figure 5 , 6 As shown, multiple tooth plates 75 are elastically rotated by torsion springs in the integrated box 71, and the tooth plates 75 span the driving rod 9 to engage the driving gears 74 one by one. The portion where the tooth plates 75 are engaged with the driving gears 74 is an arc-shaped tooth surface, which is used to lock the angle of the driving gear 74. The portion where the tooth plates 75 span the driving rod 9 is a smooth plate surface. The fins 92 protrude from the surface of the rod body 91 and engage with the driving gear 74. At the same time, the fins 92 push the tooth plates 75 to rotate and disengage from the driving gear 74, automatically unlocking the lock on the driving gear 74, and facilitating and quickly adjusting the angles of the front reflector 3, the beam combiner 31, the beam splitter 32, and the rear reflector 33.

[0037] like Figure 8 As shown, a telescopic groove 99 is provided on the inner wall of the shaft tube 710, and a ball 98 is elastically slid in the telescopic groove 99 by a spring, and a plurality of annular grooves 97 are arranged on the surface of the rod body 91, and the spacing of the annular grooves 97 is the same as the spacing of the belt assembly. During the process of pulling and inserting the rod body 91, the ball 98 can be stuck in the annular groove 97 to locate the sliding position of the rod body 91, and the frustration feeling caused by the elastic clamping of the ball 98 and the annular groove 97 can be used to accurately judge whether the rod body 91 is adjusted in place.

[0038] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A detection device for optical crystal laser thermal lens effect, comprising: A pump laser (1), a detection red light laser (2) and a power detector (4), characterized in that a beam combining mirror (31), a crystal sample stage (6) and a beam splitter (32) are sequentially arranged along the beam direction of the pump laser (1); the crystal sample stage (6) is used to position the optical crystal; a front reflector (3) is arranged in the beam direction of the detection red light laser (2); the front reflector (3) is used to reflect the beam of the detection red light laser (2) in the direction of the beam combining mirror (31), so that the beam of the detection red light laser (2) overlaps with the beam of the pump laser (1) and passes through the optical crystal; a rear reflector (33) is arranged corresponding to the power detector (4); the beam of the detection red light laser (2) is sequentially reflected by the beam splitter (32) and the rear reflector (33) and then guided to the power detector (4).

2. The detection device of optical crystal laser thermal lens effect according to claim 1, characterized in that: A light beam trash can (5) is provided corresponding to the beam splitter (32), and the light beam of the pump laser (1) passes through the beam splitter (32) and is guided to the light beam trash can (5).

3. The detection device of optical crystal laser thermal lens effect according to claim 1, characterized in that: The invention also comprises an angle adjuster (7), which comprises an integrated box (71), wherein four groups of belt assemblies are arranged in an array in the integrated box (71), wherein the front reflector (3), the beam combining mirror (31), the beam splitter (32), and the rear reflector (33) are all connected to the belt assemblies through belts, and a drive rod (9) is arranged in the integrated box (71) along the arrangement direction of the belt assemblies, wherein the drive rod (9) can be engaged with one of the four groups of belt assemblies by the displacement of the drive rod (9), and the drive rod (9) can be rotated to select one of the four groups of belt assemblies for transmission and adjustment.

4. The optical crystal laser thermal lens effect detection device according to claim 3, characterized in that: The belt assembly comprises a driving pulley (72); the front reflector (3), the beam combining mirror (31), the beam splitter (32), and the rear reflector (33) are all rotatably mounted on the surface of the bracket via a damping bearing; the reflector, the beam combining mirror (31), the beam splitter (32), and the rear reflector (33) are all coaxially fixed with a driven pulley (8); the driven pulley (8) is connected to the driving pulley (72) via a belt transmission; the driving pulley (72) is coaxially fixed with a driven gear (73); the driven gear (73) is meshingly connected to a driving gear (74); and the driving rod (9) can be selectively meshedly connected to the driving gear (74).

5. The detection device of optical crystal laser thermal lens effect according to claim 4, characterized in that: A tensioning wheel (76) is arranged in correspondence with the driving pulley (72), and a belt on the outer side of the driving pulley (72) passes around the tensioning wheel (76). The tensioning wheel (76) is swingably connected to the integrated box (71) via a swing frame (77). A stud (78) is rotatably connected to the surface of the swing frame (77). The surface of the integrated box (71) has a through opening (79). The stud (78) passes through the through opening (79) to the outside of the integrated box (71). A nut is threadedly connected to the surface of the stud (78). The nut contacts the outer wall of the integrated box (71) to pull the swing frame (77) outward, so that the tensioning wheel (76) tightens the belt.

6. The detection device of optical crystal laser thermal lens effect according to claim 4, characterized in that: The driving rod (9) comprises a rod body (91); a shaft cylinder (710) is provided on the surface of the integrated box (71); the rod body (91) is inserted into the integrated box (71) by linear sliding of the shaft cylinder (710); a plurality of pressure plates (93) are rotatably arranged around the outer end of the rod body (91); the inner edges of the pressure plates (93) are inclined toward the inner end of the rod body (91); a plurality of fins (92) are rotatably arranged around the inner end of the rod body (91) by means of a torsion spring; the inner edges of the fins (92) are inclined toward the outer end of the rod body (91); An axial rod (94) is arranged inside the rod body (91) for axial sliding. The axial rod (94) is connected to a spring for applying pressure to the outer end of the rod body (91). The two ends of the axial rod (94) are respectively fixed to a rear sphere (95) and a front sphere (96). The rear sphere (95) contacts the inner edge of the pressure plate (93), and the front sphere (96) contacts the inner edge of the fin (92). By pressing the pressure plate (93) to contact the rear sphere (95) and the front sphere (96) to move, the front sphere (96) squeezes the fin (92) to rotate and protrude from the surface of the rod body (91).

7. The detection device of optical crystal laser thermal lens effect according to claim 6, characterized in that: A plurality of tooth plates (75) are elastically rotated in the integrated box (71) by means of a torsion spring, and the tooth plates (75) are arranged across the driving rod (9) to engage with the driving gears (74) one by one. The fins (92) protrude from the surface of the rod body (91) to engage with the driving gears (74), and at the same time, the fins (92) push the tooth plates (75) to rotate and disengage from the engagement with the driving gears (74).

8. The detection device of optical crystal laser thermal lens effect according to claim 7, characterized in that: The portion where the tooth plate (75) is engaged with the driving gear (74) is an arc-shaped tooth surface, and the portion where the tooth plate (75) crosses the driving rod (9) is a smooth plate surface.

9. The optical crystal laser thermal lens effect detection device according to claim 6, characterized in that: The inner wall of the shaft cylinder (710) is provided with a telescopic groove (99), in which a ball (98) slides elastically through a spring, and a plurality of annular grooves (97) are arranged on the surface of the rod body (91), in which the ball (98) can be inserted, and the spacing of the annular grooves (97) is the same as the spacing of the belt assembly.

10. A method for detecting the optical crystal laser thermal lens effect based on the optical crystal laser thermal lens effect detection device according to any one of claims 1 to 9, characterized in that: The specific steps are as follows: A. Beam debugging: Turn on the pump laser (1) and the detection red light laser (2). The light beam of the pump laser (1) passes through the beam combiner (31), the optical crystal, and the beam splitter (32) in sequence. The light beam of the detection red light laser (2) passes through the front reflector (3) and the beam combiner (31) and passes through the optical crystal. It is then reflected to the power detector (4) by the beam splitter (32) and the rear reflector (33). The reflection angles of the front reflector (3), the beam combiner (31), the beam splitter (32), and the rear reflector (33) are coordinated and rotated so that the light beams of the pump laser (1) and the detection red light laser (2) overlap and pass through the optical crystal, and ensure that the light beam of the detection red light laser (2) is accurately guided to the power detector (4). B. Background noise collection: turn off the detection red light laser (2), turn on the pump laser (1), and increase the beam power of the pump laser (1) in sequence to obtain the background noise of the power detector (4); C. Variable power signal acquisition: Turn on the pump laser (1) and the detection red light laser (2). The light beam of the pump laser (1) heats the optical crystal. After the light beam of the detection red light laser (2) passes through the optical crystal, the light intensity at the center of the diffraction spot is detected by the power detector (4). Then, the power of the beam of the pump laser (1) is increased in a gradient manner. The light beam of the detection red light laser (2) is detected multiple times to obtain a trend line of the light intensity at the center of the diffraction spot changing with the pump power. The slope of the trend line is used to feed back the intensity of the thermal lens effect of the optical crystal.

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