A 10μm picosecond solid-state laser based on a dual-pass optical parametric generator

Abstract

A 10μm picosecond solid-state laser based on a dual-pass parametric generator belongs to the field of optical technology. It addresses the problems of low beam quality, low optical conversion efficiency, and poor spectral stability inherent in 10μm picosecond lasers. The process includes: pump light being converted into 2.63μm and 10μm laser beams by a first ZnGeP2 crystal; this, along with the remaining pump light, is incident on a second ZnGeP2 crystal and a gold mirror; the light is then reflected back to the second and first ZnGeP2 crystals; the remaining pump light and the 10μm laser beam are transmitted through a first dichroic mirror; the 2.63μm laser beam is reflected by the first dichroic mirror; the 2.63μm laser beam and the pump light are then processed by a third ZnGeP2 crystal to generate a 10μm laser beam, amplifying the 2.63μm laser beam; the remaining pump light, the 2.63μm laser beam, and the 10μm laser beam are non-critically phase-matched by a BaGa4Se7 crystal; and the 10μm laser beam is transmitted and output through a dichroic mirror. This process is used to generate a 10μm picosecond laser.

Description

Technical Field

[0001] This invention relates to a 10μm picosecond solid-state laser, belonging to the field of optical technology. Background Technology

[0002] The 10μm picosecond laser is an important mid-infrared ultrafast light source, widely used in precision materials processing, biomedical imaging, infrared spectroscopy analysis, infrared communication, and nonlinear optics research. Compared with nanosecond or continuous-wave (CW) lasers, picosecond ultrashort pulses can effectively reduce the heat-affected zone, improve the precision of materials processing, and enhance adaptability to transparent and highly reflective materials.

[0003] Currently, the main technological approaches to achieving 10μm picosecond lasers include direct CO lasers, fiber lasers, solid-state lasers, and methods based on nonlinear frequency conversion such as difference frequency generation (DFG), optical parametric oscillator (OPO), and optical parametric amplification (OPA). Among these, CO lasers, based on a gas discharge gain mechanism, can directly generate high-power lasers at 10μm, but they are relatively large and have limited wavelength tuning capabilities. In contrast, 2μm laser systems based on optical fibers and solid-state gain media, combined with nonlinear frequency conversion techniques (DFG, OPO, OPA), have become an important solution for obtaining high-power, high-beam-quality 10μm picosecond lasers.

[0004] In recent years, breakthroughs in solid-state and fiber lasers at the 2μm wavelength have laid the foundation for the development of 10μm picosecond lasers. For example, holmium-doped (Ho), thulium-doped (Tm), or co-doped (Tm, Ho) laser crystals (such as Ho:YAG, Ho:YLF, Ho:LuAG) and thulium-doped fiber (TDFL) can generate high-energy ultrafast pulses at 2μm. Subsequently, these pulses can be efficiently converted to the 10μm wavelength through difference-frequency generation (DFG) or optical parametric processes (OPO / OPA). Among these, nonlinear crystals such as ZnGeP, AgGaSe, and GaSe have been widely used in the research of high-power 10μm picosecond lasers due to their high nonlinear coefficients and good phase-matching characteristics.

[0005] Currently, the output power of 10μm picosecond solid-state lasers has reached the tens of watts level, with pulse energies reaching hundreds of microjoules and repetition frequencies covering the MHz level, meeting the needs of high-precision laser processing, infrared spectroscopy detection, and nonlinear optical experiments. Particularly in the field of precision manufacturing, this wavelength laser demonstrates significant advantages in the micromachining and fine etching of polymer materials, ceramics, semiconductors, and biological tissues.

[0006] In biomedical applications, 10μm picosecond lasers can be used for photothermal therapy, nonlinear microscopy, and far-infrared diagnostics, driving the development of high-precision medical technologies.

[0007] In addition, to further improve conversion efficiency and output power, researchers have been exploring nonlinear cascaded conversion schemes in recent years, such as OPO-cascaded DFG or OPA-cascaded DFG structures, to achieve higher energy conversion efficiency and optimize the phase matching conditions of the nonlinear medium to reduce conversion loss and improve beam quality.

[0008] With the continuous development of high-power solid-state lasers, fiber lasers, and mid-infrared nonlinear frequency conversion technology, the application potential of 10μm picosecond lasers will be further expanded, and it will become one of the important research directions in the field of ultrafast laser technology. Summary of the Invention

[0009] The purpose of this invention is to solve the problems of low beam quality, low optical conversion efficiency and poor spectral stability of 10μm picosecond solid-state lasers, and to provide a 10μm picosecond solid-state laser based on a dual-pass optical parametric generator.

[0010] The present invention discloses a 10μm picosecond solid-state laser based on a dual-pass parametric generator, comprising: a first plano-convex lens, a second plano-convex lens, a pump beam splitter, a first dichroic mirror, a second dichroic mirror, a first ZnGeP2 crystal, a second ZnGeP2 crystal, a third ZnGeP2 crystal, a gold mirror, a reflector, a BaGa4Se7 crystal, a third dichroic mirror, and a fourth dichroic mirror;

[0011] The first plano-convex lens and the pump beam splitter constitute a first coupling system, and the reflector and the second plano-convex lens constitute a second coupling system.

[0012] Picosecond pulse pump laser is incident perpendicularly onto the first coupling system. After beam transformation, part of the pump light is reflected to the mirror by the pump light beam splitter, and the other part of the pump light is incident on the first dichroic mirror at an incident angle of 45°.

[0013] Pump light passing through the first dichroic mirror is incident on the first ZnGeP2 crystal. Part of the pump light is converted into 2.63μm laser and 10μm laser. The other part of the pump light, 2.63μm laser and 10μm laser are incident on the second ZnGeP2 crystal. After being amplified, they are incident on the gold mirror. After being reflected and deflected, they are reflected back to the second ZnGeP2 crystal. After being amplified, they are reflected back to the first ZnGeP2 crystal. The remaining pump light and 10μm laser are transmitted through the first dichroic mirror, and the 2.63μm laser is reflected through the first dichroic mirror.

[0014] The reflected 2.63μm laser light is incident on the second dichroic mirror; the pump light reflected on the mirror passes through the second coupling system, undergoes beam transformation, and is then incident on the second dichroic mirror at an incident angle of 45°.

[0015] The 2.63μm laser and pump light, after being reflected by the second dichroic mirror, are incident on the third ZnGeP2 crystal to generate a 10μm laser, which amplifies the 2.63μm laser. The remaining pump light, the 2.63μm laser, and the 10μm laser are then incident on the BaGa4Se7 crystal. After non-critical phase matching, they pass sequentially through the third and fourth dichroic mirrors. The fourth dichroic mirror reflects the 2.63μm laser, while the 10μm laser is transmitted and output.

[0016] Preferably, the wavelength of the picosecond pulse pump laser incident on the first coupling system is 2.09 μm.

[0017] Preferably, the first dichroic mirror, the first ZnGeP2 crystal, the second ZnGeP2 crystal, and the gold mirror constitute a dual-channel ZnGeP2 optical parameter generator;

[0018] The second dichroic mirror, the third ZnGeP2 crystal, the BaGa4Se7 crystal, and the fourth dichroic mirror constitute a difference frequency generation system.

[0019] Preferably, in the dual-pass ZnGeP2 optical parameter generator, the beam quality of 2.63μm and 10μm lasers is improved by increasing the distance between the first dichroic mirror and the gold mirror.

[0020] Preferably, the first ZnGeP2 crystal uses a type II phase matching method, and the second ZnGeP2 crystal uses a type I phase matching method.

[0021] Preferably, the optical surfaces of both the first and second plano-convex lenses are coated with a 2μm high-transmittance film, the focal length range is 10mm~1000mm, and the diameter range is 10mm~100mm.

[0022] Preferably, one side of the pump beam splitter is coated with a 2μm laser partial reflective film, the transmittance of which is 10% to 90% for 2μm laser light; the other side of the pump beam splitter is coated with a 2μm antireflection film.

[0023] Preferably, one side of the first dichroic mirror and the second dichroic mirror is coated with a 2μm antireflective film, and the other side is coated with a 2μm antireflective and a 2.6μm antireflective film.

[0024] The third dichroic mirror is coated with a 2μm antireflective film and a 10μm antireflective film on one side, and a 10μm antireflective film on the other side.

[0025] The fourth dichroic mirror has a 2.6μm antireflective coating and a 10μm anti-reflective coating on one side, and a 10μm anti-reflective coating on the other side.

[0026] Preferably, the light-transmitting surfaces of both the first ZnGeP2 crystal and the second ZnGeP2 crystal are coated with 2μm and 2.6μm antireflection films, respectively.

[0027] The light-transmitting surfaces of the third ZnGeP2 crystal are all coated with 2μm and 10μm anti-reflection films;

[0028] The light-transmitting surfaces of the BaGa4Se7 crystals are all coated with 2μm and 10μm antireflection films.

[0029] Preferably, one side of the reflector is coated with a 2μm anti-reflection film.

[0030] Advantages of this invention: This invention proposes a 10μm picosecond solid-state laser based on a dual-pass optical parametric generator, providing a new design scheme for a high-power 10μm band picosecond solid-state laser. It uses a dual-pass optical parametric generator to generate 2.63μm and 10μm picosecond lasers, and has the following advantages:

[0031] 1. By employing optical parametric generation and difference frequency generation to generate 10μm picosecond lasers, significant advantages are achieved compared to traditional optical parametric generation and optical parametric amplification. The dual-pass structure improves the light conversion efficiency of the optical parametric generation process.

[0032] Due to the higher power input of the 2.63μm laser, the frequency conversion efficiency of the difference frequency generation process is significantly improved, thereby achieving higher output power and better beam quality.

[0033] Furthermore, the phase matching conditions for the difference frequency generation process are easier to achieve, which improves the overall energy conversion efficiency and reduces the dependence on high-power pump light, thereby reducing the complexity and energy consumption of the system.

[0034] Overall, the use of optical parametric generation and difference frequency generation techniques can significantly improve the conversion efficiency and system economy of 10μm lasers, making them suitable for applications with high requirements for power, beam quality and spectral stability.

[0035] This invention achieves a 2.1W 10μm pulsed laser output with a pulse width of 248ps, an optical-to-optical conversion efficiency of 5.8%, and a beam quality of 5.0 when injected with 2.09μm pump light power of 36W and a pulse width of 490ps.

[0036] 2. During the difference frequency generation process, the long-wavelength laser generated by the third ZnGeP2 crystal interacts nonlinearly with the BaGa4Se7 crystal, achieving power amplification through a frequency conversion process. Non-critical phase matching makes the entire process more efficient, thus obtaining higher long-wavelength output at the same pump power. Attached Figure Description

[0037] Figure 1This is a schematic diagram of the 10μm picosecond solid-state laser based on a dual-pass optical parametric generator as described in this invention. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0040] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0041] Example 1:

[0042] The following is combined with Figure 1 This embodiment describes a 10μm picosecond solid-state laser based on a dual-pass parametric generator, comprising: a first plano-convex lens 1-1, a second plano-convex lens 1-2, a pump beam splitter 2, a first dichroic mirror 3-1, a second dichroic mirror 3-2, a first ZnGeP2 crystal 4, a second ZnGeP2 crystal 5, a third ZnGeP2 crystal 8, a gold mirror 6, a reflecting mirror 7, a BaGa4Se7 crystal 9, a third dichroic mirror 10, and a fourth dichroic mirror 11.

[0043] The first plano-convex lens 1-1 and the pump beam splitter 2 constitute a first coupling system, and the reflector 7 and the second plano-convex lens 1-2 constitute a second coupling system.

[0044] Picosecond pulse pump laser is incident perpendicularly into the first coupling system. After beam transformation, part of the pump light is reflected by the pump light beam splitter 2 to the reflector 7, and the other part of the pump light is incident at a 45° incident angle to the first dichroic mirror 3-1.

[0045] Pump light passing through the first dichroic mirror 3-1 is incident on the first ZnGeP2 crystal 4. Part of the pump light is converted into 2.63μm laser and 10μm laser. The other part of the pump light, 2.63μm laser and 10μm laser are incident on the second ZnGeP2 crystal 5. After being amplified, they are incident on the gold mirror 6. After being reflected and deflected, they are reflected back to the second ZnGeP2 crystal 5. After being amplified, they are reflected back to the first ZnGeP2 crystal 4. The remaining pump light and 10μm laser are transmitted through the first dichroic mirror 3-1, and the 2.63μm laser is reflected through the first dichroic mirror 3-1.

[0046] The reflected 2.63μm laser light is incident on the second dichroic mirror 3-2; the pump light reflected on the mirror 7 passes through the second coupling system, undergoes beam transformation, and is then incident on the second dichroic mirror 3-2 at an incident angle of 45°.

[0047] The 2.63μm laser and pump light, after being reflected by the second dichroic mirror 3-2, are incident on the third ZnGeP2 crystal 8 to generate a 10μm laser, which amplifies the 2.63μm laser. The remaining pump light, the 2.63μm laser, and the 10μm laser are incident on the BaGa4Se7 crystal 9. After non-critical phase matching, they pass sequentially through the third dichroic mirror 10 and the fourth dichroic mirror 11. The fourth dichroic mirror 11 reflects the 2.63μm laser and transmits the 10μm laser for output.

[0048] Furthermore, the wavelength of the picosecond pulse pump laser incident on the first coupling system is 2.09 μm.

[0049] Furthermore, the first dichroic mirror 3-1, the first ZnGeP2 crystal 4, the second ZnGeP2 crystal 5, and the gold mirror 6 constitute a dual-channel ZnGeP2 optical parameter generator.

[0050] The second dichroic mirror 3-2, the third ZnGeP2 crystal 8, the BaGa4Se7 crystal 9, the third dichroic mirror 10, and the fourth dichroic mirror 11 constitute a difference frequency generation system.

[0051] Furthermore, in the dual-pass ZnGeP2 optical parameter generator, the beam quality of 2.63μm and 10μm lasers is improved by increasing the distance between the first dichroic mirror 3-1 and the gold mirror 6.

[0052] In this embodiment, by increasing the distance between the first dichroic mirror 3-1 and the gold mirror 6, the beam quality of the 2.63μm and 10μm lasers can be improved, thereby increasing the brightness of the 2.63μm and 10μm lasers. Furthermore, by changing the distance between the first dichroic mirror 3-1 and the gold mirror 6, the optical path length of the difference frequency generation process can be matched more easily, thereby improving the conversion efficiency of difference frequency generation in both time and space.

[0053] Furthermore, the first ZnGeP2 crystal 4 adopts a type II phase matching method, and the second ZnGeP2 crystal 5 adopts a type I phase matching method.

[0054] In this embodiment, a first ZnGeP2 crystal 4 and a second ZnGeP2 crystal 5 are connected in series in the dual-channel ZnGeP2 optical parametric generator. The first ZnGeP2 crystal 4 uses a type II phase-matching method, while the second ZnGeP2 crystal 5 uses a type I phase-matching method. Although the 2.63μm laser polarization states generated by the two phase-matching methods are the same, the main purpose of choosing the first ZnGeP2 crystal 4 is to obtain a narrower laser spectral width. A narrower laser spectral width helps simplify the phase-matching conditions in the difference frequency generation process, thereby improving the difference frequency conversion efficiency. Meanwhile, the second ZnGeP2 crystal 5 is selected using type I phase matching because type I phase matching has a higher nonlinear coefficient, which further improves the conversion efficiency of optical parametric generation.

[0055] Experiments show that when the dual-pass parametric generator is pumped with 15W power, using only a type I phase-matched ZnGeP crystal, the output power of the 2.63μm laser is 0.95W; using only a type II phase-matched ZnGeP crystal, the output power is 0.45W; and when both type II and type I phase-matched ZnGeP crystals are connected in series, the output power of the 2.63μm laser reaches 2.69W, and the output power of the 10μm laser is 0.15W. Injecting the 2.63μm laser into ZnGeP crystal 8 (number three) successfully outputs a 1.7W 10μm picosecond pulse laser through a difference frequency generation process. After amplification by BaGa4Se7 crystal 9, the output power of this 10μm laser is increased to 2.1W.

[0056] Furthermore, the light surfaces of the first plano-convex lens 1-1 and the second plano-convex lens 1-2 are both coated with a 2μm high-transmittance film, with a focal length range of 10mm to 1000mm and a diameter range of 10mm to 100mm.

[0057] Furthermore, one side of the pump beam splitter 2 is coated with a 2μm laser partial reflective film, the transmittance of which is 10% to 90% for 2μm laser light; the other side of the pump beam splitter 2 is coated with a 2μm antireflection film.

[0058] Furthermore, one side of the first dichroic mirror 3-1 and the second dichroic mirror 3-2 is coated with a 2μm antireflective film, and the other side is coated with a 2μm antireflective and 2.6μm antireflective film.

[0059] The third dichroic mirror 10 has a 2μm antireflective coating and a 10μm antireflective coating on one side, and a 10μm antireflective coating on the other side.

[0060] The fourth dichroic mirror 11 has a 2.6μm antireflective coating and a 10μm anti-reflective coating on one side, and a 10μm anti-reflective coating on the other side.

[0061] Furthermore, the light-transmitting surfaces of the first ZnGeP2 crystal 4 and the second ZnGeP2 crystal 5 are both coated with 2μm and 2.6μm antireflection films, respectively.

[0062] The light-transmitting surfaces of the third ZnGeP2 crystal 8 are all coated with 2μm and 10μm anti-reflection films;

[0063] The light-transmitting surfaces of the BaGa4Se7 crystal 9 are all coated with 2μm and 10μm anti-reflection films.

[0064] Furthermore, one side of the reflector 7 is coated with a 2μm anti-reflection film.

[0065] In this invention, a 2.09 μm picosecond pulse pump laser beam is perpendicularly incident on the first coupling system. After beam conversion, a portion of the pump light is reflected by the pump light beam splitter 2 to the reflector 7, while the remaining pump light enters the first dichroic mirror 3-1 at a 45° incident angle. The pump light passing through the first dichroic mirror 3-1 enters the first ZnGeP2 crystal 4. During nonlinear difference frequency conversion, a portion of the pump light is converted into 2.63 μm and 10 μm lasers. Subsequently, the 2.63 μm laser, the 10 μm laser, and the remaining pump light enter the second ZnGeP2 crystal 5, where the remaining pump light further amplifies the 2.63 μm and 10 μm lasers. The amplified 2.63 μm laser, the 10 μm laser, and the remaining pump light are incident on the gold mirror 6. After being reflected and deflected at a certain angle by the gold mirror 6, they are reinjected into the second ZnGeP2 crystal 5. Within this crystal, the remaining pump light acts again on the 2.63μm and 10μm lasers, further amplifying them. Finally, the amplified 2.63μm laser, 10μm laser, and remaining pump light re-enter the first ZnGeP2 crystal 4, achieving final amplification of the 2.63μm and 10μm lasers. Subsequently, the 10μm laser and remaining pump light are transmitted through the first dichroic mirror 3-1, realizing the output of a high-power 10μm picosecond laser.

[0066] The 2.63μm laser light reflected from the first dichroic mirror 3-1 is incident on the second dichroic mirror 3-2, and after reflection by the second dichroic mirror 3-2, it is incident on the third ZnGeP2 crystal 8. The pump light reflected to the reflector 7 is then subjected to beam transformation by the second coupling system and incident on the second dichroic mirror 3-2 at a 45° angle. The second dichroic mirror 3-2 reflects this pump light back to the third ZnGeP2 crystal 8.

[0067] The pump light incident on the third ZnGeP2 crystal 8 and the 2.63μm laser undergo a difference frequency generation process within the third ZnGeP2 crystal 8 to generate a 10μm laser, thus amplifying the 2.63μm laser. Subsequently, the 2.63μm laser, the 10μm laser, and the remaining pump light enter the BaGa4Se7 crystal 9 together. After achieving non-critical phase matching, the 2.63μm and 10μm lasers are further amplified. Because the second coupling system transforms the pump light to match its spot size and divergence angle with the 2.63μm laser, the third ZnGeP2 crystal 8 and the BaGa4Se7 crystal 9 can maximize the light-to-light conversion efficiency while ensuring good beam quality of the output 10μm laser.

[0068] The 2.63μm and 10μm laser beams emitted from the BaGa4Se7 crystal 9, along with the remaining pump light, are incident on the third dichroic mirror 10. The third dichroic mirror 10 reflects the pump light, and the 2.63μm and 10μm laser beams passing through the third dichroic mirror 10 are further incident on the fourth dichroic mirror 11. The fourth dichroic mirror 11 reflects the 2.63μm laser beam, and the 10μm laser beam passes through the fourth dichroic mirror 11 and is output.

[0069] This invention utilizes optical parametric generation and difference frequency generation to generate a 10μm picosecond laser, offering significant advantages over traditional optical parametric generation and optical parametric amplification. Due to the higher power input of the 2.63μm laser, the frequency conversion efficiency of the difference frequency generation process is significantly improved, resulting in higher output power and better beam quality. Furthermore, the phase-matching conditions of the difference frequency generation process are easier to achieve, improving overall energy conversion efficiency and reducing dependence on high-power pump light, thus lowering system complexity and energy consumption. Overall, the use of optical parametric generation and difference frequency generation techniques can significantly improve the conversion efficiency of the 10μm laser and the economics of the system, making it suitable for applications with high requirements for power, beam quality, and spectral stability.

[0070] In this nonlinear process of difference frequency generation, the use of BaGa4Se7 crystal 9 can significantly improve the long-wavelength output power. During difference frequency generation, the long-wavelength laser generated by the third ZnGeP2 crystal 8 interacts nonlinearly with the BaGa4Se7 crystal 9, achieving power amplification through a frequency conversion process. Noncritical phase matching makes the entire process more efficient, thus obtaining higher long-wavelength output at the same pump power.

[0071] This invention achieves a 2.1W 10μm pulsed laser output with a pulse width of 248ps, an optical-to-optical conversion efficiency of 5.8%, and a beam quality of 5.0 when injected with 2.09μm pump light power of 36W and a pulse width of 490ps.

[0072] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A 10μm picosecond solid-state laser based on a dual-pass parametric generator, characterized in that, It includes: First plano-convex lens (1-1), second plano-convex lens (1-2), pump beam splitter (2), first dichroic mirror (3-1), second dichroic mirror (3-2), first ZnGeP2 crystal (4), second ZnGeP2 crystal (5), third ZnGeP2 crystal (8), gold mirror (6), reflector (7), BaGa4Se7 crystal (9), third dichroic mirror (10) and fourth dichroic mirror (11); The first plano-convex lens (1-1) and the pump beam splitter (2) constitute a first coupling system, and the reflector (7) and the second plano-convex lens (1-2) constitute a second coupling system. Picosecond pulse pump laser is incident vertically into the first coupling system. After beam transformation, part of the pump light is reflected by the pump light beam splitter (2) to the reflector (7), and the other part of the pump light is incident at a 45° incident angle to the first dichroic mirror (3-1). Pump light passing through the first dichroic mirror (3-1) is incident on the first ZnGeP2 crystal (4). Part of the pump light is converted into 2.63μm laser and 10μm laser. The other part of the pump light, 2.63μm laser and 10μm laser are incident on the second ZnGeP2 crystal (5). After being amplified, they are incident on the gold mirror (6). After being reflected and deflected, they are reflected back to the second ZnGeP2 crystal (5). After being amplified, they are reflected back to the first ZnGeP2 crystal (4). The remaining pump light and 10μm laser are transmitted through the first dichroic mirror (3-1), and the 2.63μm laser is reflected through the first dichroic mirror (3-1). The reflected 2.63μm laser light is incident on the second dichroic mirror (3-2); the pump light reflected to the mirror (7) passes through the second coupling system, and after beam transformation, it is incident on the second dichroic mirror (3-2) at an incident angle of 45°. The 2.63μm laser and pump light, after being reflected by the second dichroic mirror (3-2), are incident on the third ZnGeP2 crystal (8) to generate a 10μm laser, which amplifies the 2.63μm laser. The remaining pump light, the 2.63μm laser and the 10μm laser are incident on the BaGa4Se7 crystal (9). After non-critical phase matching, they pass through the third dichroic mirror (10) and the fourth dichroic mirror (11) in sequence. The fourth dichroic mirror (11) reflects the 2.63μm laser and transmits the 10μm laser for output.

2. A 10μm picosecond solid-state laser based on a dual-pass parametric generator according to claim 1, characterized in that, The wavelength of the picosecond pulse pump laser incident on the first coupling system is 2.09 μm.

3. A 10μm picosecond solid-state laser based on a dual-pass parametric generator according to claim 2, characterized in that, The first dichroic mirror (3-1), the first ZnGeP2 crystal (4), the second ZnGeP2 crystal (5), and the gold mirror (6) constitute a dual-channel ZnGeP2 optical parameter generator; The second dichroic mirror (3-2), the third ZnGeP2 crystal (8), the BaGa4Se7 crystal (9), the third dichroic mirror (10), and the fourth dichroic mirror (11) constitute a difference frequency generation system.

4. A 10μm picosecond solid-state laser based on a dual-pass parametric generator according to claim 3, characterized in that, In the dual-pass ZnGeP2 optical parameter generator, the beam quality of 2.63μm and 10μm lasers is improved by increasing the distance between the first dichroic mirror (3-1) and the gold mirror (6).

5. A 10μm picosecond solid-state laser based on a dual-pass parametric generator according to claim 1, characterized in that, The first ZnGeP2 crystal (4) adopts a type II phase matching method, and the second ZnGeP2 crystal (5) adopts a type I phase matching method.

6. A 10μm picosecond solid-state laser based on a dual-pass parametric generator according to claim 1, characterized in that, The light surfaces of the first plano-convex lens (1-1) and the second plano-convex lens (1-2) are coated with a 2μm high-transmittance film, with a focal length range of 10mm to 1000mm and a diameter range of 10mm to 100mm.

7. A 10μm picosecond solid-state laser based on a dual-pass parametric generator according to claim 1, characterized in that, One side of the pump beam splitter (2) is coated with a 2μm laser partial reflective film, and the transmittance of the 2μm laser partial reflective film to 2μm laser is in the range of 10%~90%; the other side of the pump beam splitter (2) is coated with a 2μm antireflection film.

8. A 10μm picosecond solid-state laser based on a dual-pass parametric generator according to claim 1, characterized in that, The first dichroic mirror (3-1) and the second dichroic mirror (3-2) have a 2μm antireflection coating on one side and a 2μm antireflection and 2.6μm antireflection coating on the other side. The third dichroic mirror (10) has a 2μm antireflective coating and a 10μm antireflective coating on one side, and a 10μm antireflective coating on the other side; The fourth dichroic mirror (11) has a 2.6μm antireflective coating and a 10μm anti-reflective coating on one side, and a 10μm anti-reflective coating on the other side.

9. A 10μm picosecond solid-state laser based on a dual-pass optical parametric generator according to claim 1, characterized in that, The light-transmitting surfaces of the first ZnGeP2 crystal (4) and the second ZnGeP2 crystal (5) are both coated with 2μm and 2.6μm antireflection films, respectively. The light-transmitting surfaces of the third ZnGeP2 crystal (8) are all coated with 2μm and 10μm anti-reflection films; The light-transmitting surfaces of the BaGa4Se7 crystal (9) are all coated with 2μm and 10μm anti-reflection films.

10. A 10μm picosecond solid-state laser based on a dual-pass parametric generator according to claim 1, characterized in that, One side of the reflector (7) is coated with a 2μm anti-reflection film.

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