Pulse solid laser

Abstract

The invention belongs to the technical field of nanosecond solid laser, and provides a pulse solid laser which comprises a pumping unit used for emitting pumping light, a pumping mirror, a laser crystal, a Q-switched device, a plano-convex reflector, a first reflector, a second reflector, a frequency doubling crystal and an output mirror. The pump light is highly transmitted through the pump mirror and then enters the laser crystal to excite the laser crystal to emit continuous laser; after continuous laser emitted from the laser crystal is input into the Q-switched device, pulse laser is generated and is emitted to the first reflecting mirror; the first reflecting mirror is used for reflecting the pulse laser to the second reflecting mirror; the second reflector is used for reflecting the pulse laser to the frequency doubling crystal for frequency doubling and outputting the pulse laser through the output mirror. According to the invention, the first reflector and the second reflector are arranged to change the transmission path of the laser and shorten the length of the laser cavity so as to reduce the occupation of the transverse space of the laser equipment at the rear end, and the plano-convex reflector is arranged to compensate the thermal lens effect of the laser crystal.

Description

Technical Field

[0001] The present invention belongs to the field of nanosecond solid laser technology, and specifically relates to a pulsed solid laser. Background Art

[0002] Pulsed laser is a special form of laser output. Ordinary laser emits light in a continuous and stable manner, while pulsed laser releases high-intensity energy within an extremely short time. Through specific technical means, such as Q-switching technology, mode-locking technology, etc., the laser energy is compressed into an extremely narrow time pulse. This kind of laser has the characteristic of extremely high peak power, and the energy released instantaneously can produce powerful photothermal, photo-mechanical and other effects. In the industrial field, it can be used for fine processing of materials, such as ultra-fine cutting and drilling, and precisely acts on the materials with high energy density.

[0003] CN202021551021.X discloses a all-solid-state Raman frequency-doubled deep red laser, which includes: a pump unit, an input cavity mirror, a laser crystal, a polarizer, a first inserted mirror, a Raman crystal, a second inserted mirror, a nonlinear optical crystal and an output cavity mirror. Among them, the input cavity mirror and the output cavity mirror form a fundamental frequency light resonant cavity, and the first inserted mirror and the output cavity mirror form a Raman light resonant cavity.

[0004] In the above technical solution, mainly through the solid Raman laser technology to generate deep red laser with good beam quality. However, in this solution, a linear resonant cavity is used when outputting high-power pulsed laser, which will lead to an increase in the length of the laser cavity structure, and the increase in the length of the cavity structure will also occupy the lateral space of the rear-end laser equipment. Summary of the Invention

[0005] The purpose of the present invention is to solve the above problems, and provides a pulsed solid laser. The laser changes the transmission path of the laser by setting a first reflector and a second reflector, shortens the length of the laser cavity, so as to reduce the occupation of the lateral space of the rear-end laser equipment, and compensates for the thermal lens effect of the laser crystal by setting a plano-convex reflector.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A pulsed solid laser, including a pump unit for emitting pump light, a pump mirror, a laser crystal, a Q-switching device, a plano-convex reflector, a first reflector, a second reflector, a frequency-doubling crystal and an output mirror;

[0008] The pump light is highly transmitted through the pump mirror and then enters the laser crystal to excite the laser crystal to emit continuous laser;

[0009] The continuous laser emitted from the laser crystal enters the Q-switching device and then generates pulsed laser and shoots towards the first reflector;

[0010] The first reflecting mirror is used to reflect the pulsed laser onto the second reflecting mirror;

[0011] The second reflecting mirror is used to reflect the pulsed laser onto the frequency doubling crystal for frequency doubling and output through the output mirror;

[0012] The reflecting surface of the pump mirror is used to reflect the continuous laser at an angle onto the plano-convex reflecting mirror, thereby compensating for the thermal lens effect of the laser crystal.

[0013] In the above-mentioned pulsed solid laser, the pump mirror, the plano-convex reflecting mirror, the first reflecting mirror, the second reflecting mirror and the output mirror form an optical resonator with an M-shaped structure. The pump mirror, the first reflecting mirror and the second reflecting mirror are respectively arranged at three turning points of the optical resonator, and the plano-convex reflecting mirror and the output mirror are respectively arranged at both ends of the optical resonator.

[0014] In the above-mentioned pulsed solid laser, the pump mirror is a flat-flat mirror, the thickness of the pump mirror is 3 mm, one side of the pump mirror is coated with a 1064 nm high-reflection film and an antireflection film of 808 nm, 878 nm or 888 nm, and the other side is coated with an antireflection film of 808 nm, 878 nm or 888 nm.

[0015] In the above-mentioned pulsed solid laser, the first reflecting mirror is a flat-flat mirror, the thickness of the first reflecting mirror is 8 mm, one side of the first reflecting mirror is coated with a 1064 nm high-reflection film and an antireflection film of 808 nm, 878 nm or 888 nm, and the other side is coated with an antireflection film of 808 nm, 878 nm or 888 nm;

[0016] The second reflecting mirror is a flat-flat mirror, the thickness of the second reflecting mirror is 8 mm, one side of the second reflecting mirror is coated with a 1064 nm high-reflection film and an antireflection film of 808 nm, 878 nm or 888 nm, and the other side is coated with an antireflection film of 808 nm, 878 nm or 888 nm.

[0017] In the above-mentioned pulsed solid laser, the pump unit includes a pump source for emitting pump light, a collimating lens and a focusing lens; the focal length ratio of the lens groups of the collimating lens and the focusing lens is 1:2, 1:2.5, 1:3 or 1:4.

[0018] In the above-mentioned pulsed solid laser, the laser crystal is a laser gain medium. The laser crystal generates 1064 nm continuous laser by stimulated emission. The laser crystal is one of neodymium-doped yttrium vanadate crystal, neodymium-doped yttrium aluminum garnet crystal, neodymium-doped gadolinium vanadate crystal, ytterbium-doped yttrium aluminum garnet crystal, neodymium-doped yttrium aluminate crystal, neodymium-doped gadolinium potassium tungstate crystal or neodymium-doped yttrium lithium fluoride crystal; the frequency doubling crystal is one of LBO crystal, KTP crystal, BBO crystal, CLBO crystal or KDP crystal.

[0019] In the above-mentioned pulsed solid-state laser, an insert mirror is further included, which is disposed between the second mirror and the frequency doubling crystal. The insert mirror is a plane-parallel mirror with a thickness of 8 mm. One side of the insert mirror is coated with a 532 nm high reflection film and a 1064 nm antireflection film, and the other side is coated with a 1064 nm antireflection film.

[0020] In the above-mentioned pulsed solid-state laser, a polarizer is further included, which is disposed between the second mirror and the insert mirror. The polarizer is used to output linearly polarized 1064 nm pulsed laser.

[0021] The polarizer is a plane-parallel mirror with a thickness of 1 mm. One side of the polarizer is coated with a P-polarized light antireflection film for 1064 nm oscillating laser and an S-polarized light high reflection film for 1064 nm oscillating laser, and the other side is coated with a P-polarized light antireflection film for 1064 nm oscillating laser.

[0022] In the above-mentioned pulsed solid-state laser, the radius of curvature of the plano-convex mirror is 200 mm, 300 mm, 400 mm, 500 mm, 600 mm or 700 mm, and the plano-convex mirror is coated with a 1064 nm high reflection film.

[0023] In the above-mentioned pulsed solid-state laser, the output mirror is a plane-parallel mirror with a coating of 532 nm transmittance of 99.8%.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] In the present invention, by arranging the first mirror and the second mirror, the transmission path of the laser is changed, the length of the laser cavity is shortened, so as to reduce the occupation of the lateral space of the rear-end laser equipment, and by arranging the plano-convex mirror, the thermal lens effect of the laser crystal is compensated. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the optical path diagram of a pulsed solid-state laser according to Embodiment 1;

[0027] Among them, the reference numerals in each figure are as follows:

[0028] 1. Pumping unit; 11. Pumping source; 12. Collimating lens; 13. Focusing lens; 2. Pumping mirror; 3. Laser crystal; 4. Q-switching device; 5. Plano-convex mirror; 6. First mirror; 7. Second mirror; 8. Frequency doubling crystal; 9. Output mirror; 101. Polarizer; 102. Insert mirror. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] Embodiment 1

[0031] Reference Figure 1 , a pulsed solid-state laser, comprising a pump unit 1 for emitting pump light, a pump mirror 2, a laser crystal 3, a Q-switching device 4, a plano-convex mirror 5, a first mirror 6, a second mirror 7, a frequency-doubling crystal 8, and an output mirror 9;

[0032] The pump light is highly transmitted through the pump mirror 2 and then enters the laser crystal 3, exciting the laser crystal 3 to emit continuous laser light;

[0033] The continuous laser light emitted from the laser crystal 3 enters the Q-switching device 4 and then generates pulsed laser light and shoots towards the first mirror 6;

[0034] The first mirror 6 is used to reflect the pulsed laser light onto the second mirror 7;

[0035] The second mirror 7 is used to reflect the pulsed laser light onto the frequency-doubling crystal 8 for frequency doubling and output through the output mirror 9;

[0036] The reflecting surface of the pump mirror 2 is used to reflect the continuous laser light at an angle onto the plano-convex mirror 5, thereby compensating for the thermal lens effect of the laser crystal 3.

[0037] It should be noted here that the Q-switching device 4 can adopt an acousto-optic Q-switch or an electro-optic Q-switch.

[0038] In this design, the pump unit 1 emits pump light. The pump light is highly transmitted through the pump light and then enters the laser crystal 3. The laser crystal 3 is stimulated to emit continuous laser light. The emitted continuous laser light outputs pulsed laser light after passing through the Q-switching device 4. The output pulsed laser light is reflected by the first mirror 6 onto the second mirror 7, and then reflected by the second mirror 7 onto the frequency-doubling crystal 8 for frequency doubling and then the pulsed laser light is output through the output mirror 9. At the same time, when the thermal lens effect occurs in the laser crystal 3, the converging laser light is reflected by the reflecting surface of the pump mirror 2 behind the plano-convex lens. The plano-convex lens is used to diverge the converging laser light and reflect it back to the pump mirror 2, thereby compensating for the thermal lens effect of the laser crystal 3. Then, it is reflected by the pump mirror 2 and output through the Q-switching, the first mirror 6, the second mirror 7, the frequency-doubling crystal 8, and the output mirror 9; In this way, the length of the laser cavity is shortened to reduce the occupation of the lateral space of the rear-end laser equipment.

[0039] In this embodiment, the pump mirror 2, the plano-convex mirror 5, the first mirror 6, the second mirror 7, and the output mirror 9 form an optical resonator with an M-shaped structure. The pump mirror 2, the first mirror 6, and the second mirror 7 are respectively arranged at three turning points of the optical resonator, and the plano-convex mirror 5 and the output mirror 9 are respectively arranged at both ends of the optical resonator.

[0040] Specifically, the pump mirror 2, the plano-convex mirror 5, the first mirror 6, the second mirror 7, and the output mirror 9 form an optical resonator with an M-shaped structure. The pump mirror 2, the first mirror 6, and the second mirror 7 are respectively arranged at three turning points of the optical resonator, while the plano-convex mirror 5 and the output mirror 9 are respectively arranged at both ends of the optical resonator. The five-mirror M optical resonator, this arrangement can better shorten the length of the laser cavity structure and can also compensate for the thermal lens effect of the laser crystal 3.

[0041] Preferably, the pump mirror 2 is a plane-plane mirror, the thickness of the pump mirror 2 is 3 mm, one side of the pump mirror 2 is coated with a 1064 nm high-reflection film and an 808 nm, 878 nm, or 888 nm antireflection film, and the other side is coated with an 808 nm, 878 nm, or 888 nm antireflection film.

[0042] Specifically, the pump unit 1 emits pump light, which is incident on the laser crystal 3 after passing through the pump mirror 2 with high transmittance. By setting the plano-convex mirror 5, the converging laser is directed to the plano-convex mirror 5 by the reflecting surface of the pump mirror 2 for divergence, thereby compensating for the thermal lens effect of the laser crystal 3.

[0043] Preferably, the first mirror 6 is a plane-plane mirror, the thickness of the first mirror 6 is 8 mm, one side of the first mirror is coated with a 1064 nm high-reflection film and an 808 nm, 878 nm, or 888 nm antireflection film, and the other side is coated with an 808 nm, 878 nm, or 888 nm antireflection film;

[0044] The second mirror 7 is a plane-plane mirror, the thickness of the second mirror 7 is 8 mm, one side of the second mirror is coated with a 1064 nm high-reflection film and an 808 nm, 878 nm, or 888 nm antireflection film, and the other side is coated with an 808 nm, 878 nm, or 888 nm antireflection film.

[0045] Furthermore, after the pulsed laser is reflected by the first mirror 6 to the second mirror 7, the pulsed laser is reflected by the second mirror 7 to the frequency doubling crystal 8, and after frequency doubling in the frequency doubling crystal 8, it is output through the output mirror 9. By the cooperation of the first mirror 6 and the second mirror 7, the transmission path of the laser is changed, thereby shortening the length of the laser cavity.

[0046] More preferably, the pumping unit 1 includes a pump source 11 for emitting pump light, a collimating lens 12, and a focusing lens 13; the focal length ratio of the lens groups of the collimating lens 12 and the focusing lens 13 is 1:2, 1:2.5, 1:3, or 1:4.

[0047] Furthermore, the pump source 11 emits pump light, the wavelength of the pump light can be 808 nm, 878 nm, or 888 nm, and the emitted pump light is collimated by the collimating lens 12 for the divergent pump light, and after collimating the pump light, the focusing lens 13 focuses the pump light into the laser crystal 3.

[0048] More preferably, the laser crystal 3 is a laser gain medium, the laser crystal 3 generates 1064 nm continuous laser by stimulated emission, and the laser crystal 3 is one of a neodymium-doped yttrium vanadate crystal, a neodymium-doped yttrium aluminum garnet crystal, a neodymium-doped gadolinium vanadate crystal, a ytterbium-doped yttrium aluminum garnet crystal, a neodymium-doped yttrium aluminate crystal, a neodymium-doped gadolinium potassium tungstate crystal, or a neodymium-doped yttrium lithium fluoride crystal; the frequency doubling crystal 8 is one of an LBO crystal, a KTP crystal, a BBO crystal, a CLBO crystal, or a KDP crystal.

[0049] Furthermore, the 1064 nm continuous laser generated by the stimulated emission of the laser crystal 3 is Q-switched by the Q-switching device 4 to form pulsed laser, and after frequency doubling in the frequency doubling crystal 8, it is converted into green light, and finally the green light is output through the output mirror 9.

[0050] Preferably, it further includes an insert mirror 102 disposed between the second mirror 7 and the frequency doubling crystal 8. The insert mirror 102 is a plane-parallel mirror, the thickness of the insert mirror 102 is 8 mm, one side of the insert mirror 102 is coated with a 532 nm high reflection film and a 1064 nm antireflection film, and the other side is coated with a 1064 nm antireflection film.

[0051] Specifically, green light is output at both ends of the frequency doubling crystal 8. By setting the insert cavity mirror, the green light output from one end can be reflected and then output through the output mirror 9.

[0052] In this embodiment, it further includes a polarizer disposed between the second mirror and the insert mirror. The polarizer is used to output linearly polarized 1064 nm pulsed laser;

[0053] The polarizer is a plane-parallel mirror, the thickness of the polarizer is 1 mm, one side of the polarizer is coated with a P-polarized light antireflection film of 1064 nm oscillating laser and an S-polarized light high reflection film of 1064 nm oscillating laser, and the other side is coated with a P-polarized light antireflection film of 1064 nm oscillating laser.

[0054] Specifically, the polarizer 101 outputs linearly polarized 1064 nm pulsed laser to improve the conversion efficiency of the frequency doubling crystal 8 during frequency doubling.

[0055] In this embodiment, the radius of curvature of the plano-convex mirror is 200 mm, 300 mm, 400 mm, 500 mm, 600 mm or 700 mm, and a 1064-nm high-reflection film is coated on the plano-convex mirror. By providing the plano-convex mirror 5 and coating it with a 1064-nm high-reflection film to reflect the 1064-nm continuous laser, the thermal lens effect of the laser crystal 3 is compensated accordingly.

[0056] In this embodiment, the output mirror 9 is a plane-plane mirror with a coating transmittance of 99.8% at 532 nm. The output mirror 9 is used to output pulsed laser at 532 nm.

[0057] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements or modifications can be made, and these improvements or modifications should also be regarded as the protection scope of the present invention.

Claims

1. A pulsed solid-state laser, characterized in that: It includes a pump unit for emitting pump light, a pump mirror, a laser crystal, a Q-switched device, a plano-convex reflector, a first reflector, a second reflector, a frequency doubling crystal and an output mirror; The pump light is injected into the laser crystal after passing through the high-transmittance pump mirror, thereby stimulating the laser crystal to emit continuous laser light; The continuous laser emitted from the laser crystal is input into the Q-switching device to generate pulsed laser and projected onto the first reflecting mirror; The first reflector is used to reflect the pulsed laser onto the second reflector; The second reflecting mirror is used to reflect the pulsed laser to the frequency doubling crystal for frequency doubling and output it through the output mirror; The reflective surface of the pump mirror is used to reflect the continuous laser light at an angle onto the plano-convex reflective mirror, thereby compensating for the thermal lens effect of the laser crystal.

2. A pulsed solid-state laser according to claim 1, characterized in that: The pump mirror, the plano-convex reflector, the first reflector, the second reflector and the output mirror constitute an optical resonant cavity with an M-type structure. The pump mirror, the first reflector and the second reflector are respectively arranged at three turning points of the optical resonant cavity, and the plano-convex reflector and the output mirror are respectively arranged at two ends of the optical resonant cavity.

3. A pulsed solid-state laser according to claim 1, characterized in that: The pump mirror is a flat mirror with a thickness of 3 mm. One side of the pump mirror is coated with a 1064nm high reflection film and an 808nm, 878nm or 888nm anti-reflection film, and the other side is coated with an 808nm, 878nm or 888nm anti-reflection film.

4. A pulsed solid-state laser according to claim 1, characterized in that: The first reflector is a flat mirror, the thickness of the first reflector is 8 mm, one side of the first reflector is coated with a 1064nm high reflection film and an 808nm, 878nm or 888nm anti-reflection film, and the other side is coated with an 808nm, 878nm or 888nm anti-reflection film; The second reflector is a flat mirror, the thickness of the second reflector is 8 mm, one side of the second reflector is coated with a 1064nm high reflection film and an 808nm, 878nm or 888nm anti-reflection film, and the other side is coated with an 808nm, 878nm or 888nm anti-reflection film.

5. A pulsed solid-state laser according to claim 1, characterized in that: The pump unit comprises a pump source for emitting pump light, a collimating lens and a focusing lens; the focal length ratio of the lens group of the collimating lens and the focusing lens is 1:2, 1:2.5, 1:3 or 1:

4.

6. A pulsed solid-state laser according to claim 1, characterized in that: The laser crystal is a laser gain medium, and the laser crystal generates 1064nm continuous laser by stimulated radiation. The laser crystal is one of neodymium-doped yttrium vanadate crystal, neodymium-doped yttrium aluminum garnet crystal, neodymium-doped gadolinium vanadate crystal, ytterbium-doped yttrium aluminum garnet crystal, neodymium-doped yttrium aluminum oxide crystal, neodymium-doped potassium gadolinium tungstate crystal or neodymium-doped lithium yttrium fluoride crystal; the frequency doubling crystal is one of LBO crystal, KTP crystal, BBO crystal, CLBO crystal or KDP crystal.

7. A pulsed solid-state laser according to claim 6, characterized in that: It also includes an inserted mirror arranged between the second reflector and the frequency doubling crystal, the inserted mirror is a flat mirror, the thickness of the inserted mirror is 8mm, one side of the inserted mirror is coated with a 532nm high reflection film and a 1064nm anti-reflection film, and the other side is coated with a 1064nm anti-reflection film.

8. A pulsed solid-state laser according to claim 7, characterized in that: It also includes a polarizer disposed between the second reflector and the insertion mirror, the polarizer being used to output a linearly polarized 1064nm pulsed laser; The polarizer is a flat mirror with a thickness of 1 mm. One side of the polarizer is coated with a P-polarized light anti-reflection film for 1064 nm oscillating laser and an S-polarized light high-reflection film for 1064 nm oscillating laser, and the other side is coated with a P-polarized light anti-reflection film for 1064 nm oscillating laser.

9. A pulsed solid-state laser according to claim 1, characterized in that: The curvature radius of the plano-convex reflector is 200 mm, 300 mm, 400 mm, 500 mm, 600 mm or 700 mm, and the plano-convex reflector is coated with a 1064 nm high-reflection film.

10. A pulsed solid-state laser according to claim 6, characterized in that: The output mirror is a flat mirror with a coated 532nm transmittance of 99.8%.

Images