High-power blue-light solid laser for urinary surgery

Abstract

The invention provides a high-power blue-light solid laser for urinary surgery, which comprises a pumping source, a pumping cavity, an annular water cooling structure, a titanium-doped sapphire slice crystal, an end mirror, a diamond crystal, a focusing system, a frequency doubling crystal, a coupling system and an optical fiber, the pumping cavity is used for reflecting 532nm pumping laser so as to focus the 532nm pumping laser on the titanium-doped sapphire slice crystal; the titanium-doped sapphire slice crystal generates 803nm laser based on 532nm pumping laser; the diamond crystal enables 803nm laser to form 900nm laser through Raman frequency shift; the focusing system is used for focusing the 900nm laser into the frequency doubling crystal so as to convert the 900nm laser into 450nm blue laser through nonlinear frequency conversion; the coupling system couples the 450nm blue laser into the optical fiber to form a stable high-power 450nm blue laser light source which can be applied to urinary surgery. The blue light laser is simple in structure, the problems that an existing blue light laser is low in output power and poor in light beam quality are solved, and operation safety and efficiency are improved.

Description

Technical Field

[0001] The invention belongs to the field of laser technology and medical treatment, and in particular relates to a high-power blue light solid laser used in urology. Background Art

[0002] Benign prostatic hyperplasia (BPH) is a common urination disorder in middle-aged and elderly men. With the acceleration of the aging process of the population, the incidence and number of patients with BPH in my country are expected to continue to increase. BPH patients usually show symptoms such as frequent urination, urgency, increased nocturia and dysuria. In severe cases, patients may experience complications such as urinary retention, hematuria, urinary tract infection, bladder stones, hydronephrosis, and even aggravate hemorrhoids or hernias, which seriously affect the health and quality of life of patients. Traditional treatments for BPH mainly include electrosurgical resection and laser surgery, the latter of which uses a variety of lasers, such as holmium laser, green laser and thulium laser. Among these technologies, blue laser stands out with its advantages of simple operation, no noise, high power and rapid vaporization, which effectively shortens the operation time. Doctors usually only need to perform four to five operations to master blue laser technology, while electrosurgical surgery requires at least fifty cases, and holmium laser may require hundreds of cases to achieve the same proficiency. In addition, 450nm blue laser cuts finely, with little bleeding and no significant coagulation side effects, showing good safety and effectiveness.

[0003] Blue light prostate vaporization has many advantages. First, it has high energy conversion efficiency, fast vaporization speed, instant hemostasis, and almost no bleeding during surgery. In addition, it has small thermal damage and thin carbonization layer, which will not damage normal tissues and nerves, thereby reducing the risk of postoperative complications. This technology can be implemented under simple anesthesia, and patients recover quickly after surgery. It is especially suitable for high-risk and complex cases, and has the conditions for day surgery. The "what you see is what you get" feature during the operation makes the operation precise and the effect visible. At the same time, its learning curve is short, and it is easy for doctors to master it. It can meet various operational requirements such as vaporization, cutting and enucleation. The equipment is small in size, low in noise, and has loose requirements for the operating environment. No special conditions are required, which expands the application range of laser surgery. These advantages make blue light prostate vaporization an efficient, safe and widely applicable treatment option. The most common 450nm blue light semiconductor laser is based on gallium nitride (GaN) material. Although this laser has a wide range of application prospects, its beam quality is poor and the power output is relatively low. Therefore, in practical applications, it is usually necessary to use complex spatial beam combining and polarization beam combining technologies to improve performance. In addition, all-solid-state blue lasers generate blue light through nonlinear frequency conversion technology. For example, through a type I critical phase-matched lithium triborate (LBO) crystal, the 1030nm laser of the ytterbium-doped yttrium aluminum garnet (Yb:YAG) crystal and the 720nm laser of the praseodymium-doped lithium yttrium fluoride (Pr:YAG) crystal are intracavitated and frequency-matched to generate a 424nm blue light source; or the 1047nm and 914nm fundamental frequency lights generated by Nd:YLF and Nd:YVO4 crystals are used to perform type I phase matching through LBO crystals to obtain a 488nm blue light source; or Nd3+:YAG is frequency-doubled at 1319nm to first generate a 660nm quasi-continuous red laser, which is then mixed with a 1319nm laser to ultimately achieve the output of a 440nm blue laser. However, the above methods usually involve multiple laser light sources of different wavelengths and require precise phase matching. Only when the power of the input light is high enough can a significant sum frequency signal be generated. Another method is based on the quasi-three-level operation mode of the Nd:YLF laser crystal, using gain suppression technology to suppress the main emission peak 1047nm laser output of the Nd:YLF crystal, generate a 908nm fundamental frequency laser, and then achieve 454nm band laser output through frequency doubling. The overall design of these systems is relatively complex, the efficiency of blue light generation is relatively low, and the power output is difficult to meet the high requirements for laser resection in urological surgery. The complex system structure and low power output have become the main obstacles limiting the widespread application of high-efficiency blue light lasers in surgical operations, especially urological surgeries.

[0004] In view of this, how to provide a high-power blue light solid laser for application in urology to solve the problem of low output power and poor beam quality of existing blue light lasers is a technical problem to be solved in this technical field. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention proposes a high-power blue light solid laser, which solves the problems of low output power and poor beam quality of the existing blue light laser.

[0006] To achieve the above-mentioned object, the present invention provides a high-power blue light solid-state laser, which comprises: a pump source, a pump cavity, an annular water-cooling structure, a titanium-doped sapphire thin slice crystal, an end mirror, a diamond crystal, a focusing system, a frequency doubling crystal, a coupling system and an optical fiber, wherein the titanium-doped sapphire thin slice crystal is fixed to the end face of the diamond crystal, a first resonant cavity is formed between the titanium-doped sapphire thin slice crystal and the end mirror, and a second resonant cavity is formed between the diamond crystal and the end mirror; wherein the pump source is used to output a 532nm pump laser, and the pump cavity is used to reflect the 532nm pump laser to focus on the titanium-doped sapphire thin slice crystal; the titanium-doped sapphire thin slice crystal is used to generate an 803nm laser based on the 532nm pump laser, and the The 803nm laser oscillates back and forth in the round-trip optical path provided by the first resonant cavity; the diamond crystal is used to form a 900nm laser through Raman frequency shift of the 803nm laser generated by the titanium-doped sapphire thin crystal, and the 900nm laser oscillates back and forth in the round-trip optical path provided by the second resonant cavity; the annular water-cooling structure is arranged around the diamond crystal to dissipate heat for the diamond crystal and the titanium-doped sapphire crystal; the focusing system is used to focus and align the 900nm laser transmitted from the second resonant cavity into the frequency-doubling crystal; the frequency-doubling crystal is used to perform nonlinear frequency conversion of the 900nm laser into a 450nm blue light laser; the coupling system couples the generated 450nm blue light laser into the optical fiber.

[0007] Preferably, the titanium-doped sapphire thin crystal is fixed to the end face of the diamond crystal by direct bonding technology, and the titanium-doped sapphire thin crystal is in the shape of a thin disk with a thickness of 50 μm to 500 μm and a diameter of 3 mm to 15 mm.

[0008] Preferably, the diamond crystal surface processing flatness error is less than 5 μm, the bonding interface tensile strength is greater than 15 MPa@20°-120°, the bonding surface intercalation thickness is less than 50 nm, and the in-plane residual stress is less than 100 MPa.

[0009] Preferably, the side of the titanium-doped sapphire thin crystal facing the first resonant cavity is coated with an anti-reflection film for the 532nm pump laser and the 803nm laser, and the transmittance of the anti-reflection film for the 532nm pump laser and the 803nm laser is greater than 99.9%; the side of the titanium-doped sapphire thin crystal facing away from the first resonant cavity is coated with a high-reflection film for the 532nm pump laser and a partially reflective and partially transparent film for the 803nm laser, and the reflectivity of the high-reflection film for the 532nm pump laser is greater than 99.9%, and the transmittance of the partially reflective and partially transparent film for the 803nm laser is in the range of 1% to 20%.

[0010] Preferably, the side of the diamond crystal facing the second resonant cavity is coated with an anti-reflection film for the 803nm laser, and the transmittance of the anti-reflection film for the 803nm laser is greater than 99.9%, and the side of the diamond crystal facing away from the second resonant cavity is coated with a high-reflection film for the 803nm laser and the 900nm laser, and the reflectivity of the high-reflection film for the 803nm laser and the 900nm laser is greater than 99.9%.

[0011] Preferably, the length of the diamond crystal along the direction of the second resonant cavity is 5 mm to 10 mm, the length of the diamond crystal along the radial direction of the titanium-doped sapphire thin crystal is 3 mm, and the diamond crystal is made by crystal face cutting.

[0012] Preferably, the end mirror is a plano-concave mirror, the radius of curvature of the concave side of the plano-concave mirror is greater than the length of the second resonant cavity, the concave side of the plano-concave mirror faces the first resonant cavity or the second resonant cavity, and the planar side of the plano-concave mirror faces away from the first resonant cavity or the second resonant cavity.

[0013] Preferably, the concave side of the end mirror is coated with a high-reflective film for 803nm laser, with a reflectivity greater than 99.9%. The concave side of the end mirror is also coated with a partially reflective and partially transparent film for 900nm laser, with a transmittance range of 1% to 20%. The flat side of the end mirror is coated with an anti-reflection film for 900nm laser, with a transmittance greater than 99.9%.

[0014] Preferably, the focusing system includes a first lens and a second lens, the first lens is located between the end lens and the second lens, the focal length of the first lens is greater than the focal length of the second lens, and the focal points of the first lens and the second lens are placed to overlap.

[0015] Preferably, the frequency doubling crystal is a BBO crystal or an LBO crystal. When the frequency doubling crystal is a BBO crystal, the phase matching angle is set to 26.1°; when the frequency doubling crystal is an LBO crystal, the phase matching angle is set to 22.9°.

[0016] Compared with the prior art, the above technical solution conceived by the invention can achieve the following beneficial effects:

[0017] Specifically, the present invention proposes a high-power blue light solid-state laser for urological surgery, which is used to output high-power 450nm blue light laser, and specifically includes a pump source, a pump cavity, an annular water-cooling structure, a titanium-doped sapphire thin slice crystal, an end mirror, a diamond crystal, a focusing system, a frequency doubling crystal, a coupling system and an optical fiber. The titanium-doped sapphire thin slice crystal is fixed to the end face of the diamond crystal, a first resonant cavity is formed between the titanium-doped sapphire thin slice crystal and the end mirror, and a second resonant cavity is formed between the diamond crystal and the end mirror; wherein the pump source is used to output a 532nm pump laser, and the pump cavity is used to reflect the 532nm pump laser to focus on the titanium-doped sapphire thin slice crystal; the titanium-doped sapphire thin slice crystal is used to generate an 803nm laser based on the 532nm pump laser, and the 803 The nm laser oscillates back and forth in the round-trip optical path provided by the first resonant cavity; the diamond crystal is used to form a 900nm laser through Raman frequency shift of the 803nm laser generated by the titanium-doped sapphire thin crystal, and the 900nm laser oscillates back and forth in the round-trip optical path provided by the second resonant cavity; an annular water-cooling structure is arranged around the diamond crystal to dissipate heat for the diamond crystal and the titanium-doped sapphire crystal; the focusing system is used to focus and align the 900nm laser transmitted from the second resonant cavity into the frequency-doubling crystal; the frequency-doubling crystal is used to perform nonlinear frequency conversion of the 900nm laser into a 450nm blue light laser; the coupling system couples the generated 450nm blue light laser into the optical fiber to form a stable high-power 450nm blue light laser light source that can be used in urological surgery. This application integrates the titanium-doped sapphire thin crystal on the end face of the diamond crystal, so that the 803nm laser generated by the titanium-doped sapphire crystal in the first resonant cavity can directly stimulate the Raman effect of the diamond crystal, thereby generating a 900nm laser, which effectively simplifies the device design of the resonant cavity, reduces the complexity of the system, and improves the energy conversion efficiency of the laser. At the same time, due to the excellent thermal conductivity of the diamond crystal, the diamond crystal also serves as an efficient heat dissipation medium for the titanium-doped sapphire thin crystal, which can effectively reduce the thermal load of the titanium-doped sapphire thin crystal to improve the stability and efficiency of the laser under high-power pumping conditions, thereby meeting the application requirements of urological surgery. The surrounding layout of the annular water-cooling structure significantly improves the tolerance of the crystal under high-power pumping, and improves the overall performance and work efficiency by effectively controlling and stabilizing the crystal temperature. This cooling mechanism ensures that the laser can continue to operate stably under high-power laser pumping conditions, further supporting the clinical application of high-power blue lasers in urology. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A structural device diagram of a high-power blue light solid-state laser for urological applications provided in an embodiment of the present invention.

[0020] Reference numerals:

[0021] 1. Pump source;

[0022] 2. Pump cavity;

[0023] 21. Collimating lens;

[0024] 22. Parabolic mirror;

[0025] 23. Total reflector;

[0026] 3. Annular water cooling structure;

[0027] 4. Titanium-doped sapphire thin crystals;

[0028] 5. Diamond crystal;

[0029] 6. The first resonant cavity;

[0030] 7. The second resonant cavity;

[0031] 8. End mirror;

[0032] 9. Focus system;

[0033] 91. The first lens;

[0034] 92. Second lens;

[0035] 10. Frequency doubling crystal;

[0036] 11. Coupling system;

[0037] 12. Optical fiber. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0039] like Figure 1 As shown, the present invention provides a high-power blue light solid laser for urology application, mainly comprising: the high-power blue light solid laser comprises: a pump source, a pump cavity, an annular water-cooling structure, a titanium-doped sapphire thin slice crystal, an end mirror, a diamond crystal, a focusing system, a frequency doubling crystal, a coupling system and an optical fiber, the titanium-doped sapphire thin slice crystal is fixed to the end face of the diamond crystal, a first resonant cavity is formed between the titanium-doped sapphire thin slice crystal and the end mirror, and a second resonant cavity is formed between the diamond crystal and the end mirror; wherein the pump source is used to output a 532nm pump laser, the pump cavity is used to reflect the 532nm pump laser to focus on the titanium-doped sapphire thin slice crystal; the titanium-doped sapphire thin slice crystal is used to generate a 532nm pump laser based on the 532nm pump laser. The light generates 803nm laser, and the 803nm laser oscillates back and forth in the round-trip optical path provided by the first resonant cavity; the diamond crystal is used to form a 900nm laser through Raman frequency shift of the 803nm laser generated by the titanium-doped sapphire thin crystal, and the 900nm laser oscillates back and forth in the round-trip optical path provided by the second resonant cavity; the annular water-cooling structure is arranged around the diamond crystal to dissipate heat for the diamond crystal and the titanium-doped sapphire crystal; the focusing system is used to focus and align the 900nm laser transmitted from the second resonant cavity into the frequency doubling crystal; the frequency doubling crystal is used to perform nonlinear frequency conversion of the 900nm laser into a 450nm blue light laser; the coupling system couples the generated 450nm blue light laser into the optical fiber.

[0040] Specifically, the embodiment of the present invention proposes a high-power blue light solid laser for urological surgery, which is used to output high-power 450nm blue light laser, and specifically includes a pump source, a pump cavity, an annular water-cooling structure, a titanium-doped sapphire thin slice crystal, an end mirror, a diamond crystal, a focusing system, a frequency doubling crystal, a coupling system and an optical fiber. The titanium-doped sapphire thin slice crystal is fixed to the end face of the diamond crystal, a first resonant cavity is formed between the titanium-doped sapphire thin slice crystal and the end mirror, and a second resonant cavity is formed between the diamond crystal and the end mirror; wherein the pump source is used to output a 532nm pump laser, and the pump cavity is used to reflect the 532nm pump laser to focus on the titanium-doped sapphire thin slice crystal; the titanium-doped sapphire thin slice crystal is used to generate an 803nm laser based on the 532nm pump laser, and the 803nm laser is generated based on the 532nm pump laser. The 803nm laser light generated by the titanium-doped sapphire thin crystal oscillates back and forth in the round-trip optical path provided by the first resonant cavity; the diamond crystal is used to form a 900nm laser light through Raman frequency shift from the 803nm laser light generated by the titanium-doped sapphire thin crystal, and the 900nm laser light oscillates back and forth in the round-trip optical path provided by the second resonant cavity; an annular water-cooling structure is arranged around the diamond crystal to dissipate heat for the diamond crystal and the titanium-doped sapphire crystal; the focusing system is used to focus and align the 900nm laser light emitted from the second resonant cavity into the frequency-doubling crystal; the frequency-doubling crystal is used to perform nonlinear frequency conversion of the 900nm laser light into a 450nm blue light laser; the coupling system couples the generated 450nm blue light laser light into the optical fiber to form a stable high-power 450nm blue light laser light source that can be used in urological surgery. The embodiment of the present application integrates the titanium-doped sapphire thin crystal on the end face of the diamond crystal, so that the 803nm laser generated by the titanium-doped sapphire crystal in the first resonant cavity can directly stimulate the Raman effect of the diamond crystal, thereby generating a 900nm laser, which effectively simplifies the device design of the resonant cavity, reduces the complexity of the system, and improves the energy conversion efficiency of the laser. At the same time, due to the excellent thermal conductivity of the diamond crystal, the diamond crystal also serves as an efficient heat dissipation medium for the titanium-doped sapphire thin crystal, which can effectively reduce the thermal load of the titanium-doped sapphire thin crystal to improve the stability and efficiency of the laser under high-power pumping conditions, thereby meeting the application requirements of urological surgery. The surrounding layout of the annular water-cooling structure significantly improves the tolerance of the crystal under high-power pumping, and improves the overall performance and work efficiency by effectively controlling and stabilizing the crystal temperature. This cooling mechanism ensures that the laser can continue to operate stably under high-power laser pumping conditions, further supporting the clinical application of high-power blue lasers in urology.

[0041] Among them, the first resonant cavity is used to provide a round-trip oscillation light path for the 803nm laser, and is formed by the cavity between the titanium-doped sapphire thin film crystal and the end mirror; the second resonant cavity is used to provide a round-trip oscillation light path for the 900nm laser and output 900nm laser, and is formed by the cavity between the diamond crystal and the end mirror.

[0042] The pump source involved in the present application includes but is not limited to a semiconductor laser, a fiber laser, a solid-state laser, etc., which output a pump laser with a wavelength of 532 nm.

[0043] The annular water cooling structure involved in the present application can be connected to an external water cooling system. The annular water cooling structure can be a water cooling pipe arranged around the periphery of the diamond crystal, and the water cooling pipe can be connected to an external water cooling system. The annular water cooling structure involved in the present application can also be a small water cooling system including an annular water cooling pipe, a water cooler, a water tank, a water pump, etc., wherein the annular water cooling pipe is arranged around the periphery of the diamond crystal.

[0044] In a possible implementation, the pump cavity of the present application may include a parabolic mirror and a series of reentrant prisms, the reentrant prisms may be total reflection mirrors, and the parabolic mirror and the series of reentrant prisms are placed in the optical path between the pump source and the titanium-doped sapphire thin crystal according to a set rule. The titanium-doped sapphire thin crystal is placed at the focus of the parabolic mirror, and the input 532nm pump laser is focused on the titanium-doped sapphire thin crystal after multiple reflections of the parabolic mirror and the reentrant prism. This embodiment adopts a 48-pass pump structure, that is, the pump laser passes through the titanium-doped sapphire thin crystal 48 times, which greatly improves the absorption efficiency of the thin crystal for pump light.

[0045] In a possible implementation, the present application provides a collimating lens between the pump source and the pump cavity, which is used to collimate the 532nm pump laser emitted by the pump source into the pump cavity, and is focused on the titanium-doped sapphire thin crystal after multiple reflections through the parabolic mirror and a series of folding prisms of the pump cavity. The collimating lens can be provided on the pump cavity.

[0046] In a possible implementation, the titanium-doped sapphire thin slice crystal is fixed to the end face of the diamond crystal by using direct bonding technology. The titanium-doped sapphire thin slice crystal is in the shape of a thin disk with a thickness of 50 μm to 500 μm and a diameter of 3 mm to 15 mm.

[0047] Furthermore, the surface processing flatness error of the diamond crystal is less than 5 μm, the bonding interface tensile strength is greater than 15 MPa@20°~120°, the bonding surface intercalation thickness is less than 50 nm, and the in-plane residual stress is less than 100 MPa.

[0048] Specifically, the titanium-doped sapphire thin crystal is used as a gain medium to generate 803nm laser and as a pump source for the diamond crystal Raman laser. Therefore, different dielectric films are plated on both sides of the titanium-doped sapphire thin crystal.

[0049] In a possible implementation, since the titanium-doped sapphire thin slice crystal is used as a gain medium to generate 803nm laser and as a pump source for the diamond crystal Raman laser, different dielectric films are coated on both sides of the titanium-doped sapphire thin slice crystal. The side of the titanium-doped sapphire thin slice crystal facing the first resonant cavity is coated with an anti-reflection film for 532nm pump laser and 803nm laser, and the transmittance of the 532nm pump laser and 803nm laser is greater than 99.9%; the side of the titanium-doped sapphire thin slice crystal facing away from the first resonant cavity is coated with a high-reflection film for 532nm pump laser and a partially reflective and partially transparent film for 803nm laser, the reflectivity of the high-reflection film for 532nm pump laser is greater than 99.9%, and the transmittance of the partially reflective and partially transparent film for 803nm laser is in the range of 1% to 20%, so as to realize the 803nm laser oscillation back and forth in the first resonant cavity.

[0050] Furthermore, the side of the diamond crystal facing the second resonant cavity or the end mirror is coated with an anti-reflection film for 803nm laser, and the transmittance of the anti-reflection film for 803nm laser is greater than 99.9%, and the side of the diamond crystal facing away from the second resonant cavity or the end mirror is coated with a high-reflection film for 803nm laser and 900nm laser, and the reflectivity of the high-reflection film for 803nm laser and 900nm laser is greater than 99.9%, so as to realize the 900nm laser oscillation back and forth in the second resonant cavity.

[0051] Meanwhile, the length of the diamond crystal along the direction of the second resonant cavity is 5 mm to 10 mm, the length of the diamond crystal along the radial direction of the titanium-doped sapphire thin crystal is 3 mm, and the diamond crystal is made by crystal face cutting.

[0052] Since the diamond crystal is used as both a Raman laser crystal to generate 900nm laser and a heat dissipation medium for titanium-doped sapphire thin crystal, the diamond crystal needs to be prepared by crystal face cutting, that is, cutting the specific

[111] face of the diamond crystal.

[0053] In a possible embodiment, the end mirror involved in the present application is a plano-concave mirror, the radius of curvature of the concave side of the plano-concave mirror is greater than the length of the second resonant cavity, the concave side of the plano-concave mirror faces the first resonant cavity or the second resonant cavity, the planar side of the plano-concave mirror faces away from the first resonant cavity or the second resonant cavity, and the planar side of the plano-concave mirror faces the frequency doubling crystal.

[0054] Furthermore, the concave side of the end mirror is coated with a high-reflection film for 803nm laser, and the reflectivity of the high-reflection film is greater than 99.9%. The concave side of the end mirror is also coated with a partially reflective and partially transparent film for 900nm laser, and the transmittance of the transparent film ranges from 1% to 20%. The flat side of the end mirror is coated with an anti-reflection film for 900nm laser, and the transmittance is greater than 99.9%.

[0055] Specifically, the end mirror is a plano-concave mirror, and the curvature of the concave side of the plano-concave mirror is related to the length of the second resonant cavity, and the curvature of the concave side is greater than the length of the second resonant cavity. Since the length of the second resonant cavity and the curvature of the concave side directly affect the laser spot size on the surface of the titanium-doped sapphire thin film crystal, in order to ensure the maximum excitation efficiency of the laser, the size of the laser spot should maintain a reasonable ratio with the size of the pump spot. Ideally, the ratio is about 80%. In this embodiment, when the pump spot size on the surface of the titanium-doped sapphire thin film crystal is adjusted to 2mm, the optimal laser spot size should be 1.6mm. In order to achieve this laser spot size, the length of the second resonant cavity can be designed to be 1m, and the radius of curvature of the concave side of the plano-concave mirror is set to 5m, thereby optimizing the overall performance of the titanium-doped sapphire thin film crystal laser and the diamond Raman laser and improving the power output efficiency.

[0056] In a possible implementation, the focusing system includes a first lens and a second lens, the first lens is between the end mirror and the second lens, the focal length of the first lens is greater than the focal length of the second lens, and the focal points of the first lens and the second lens are placed so as to overlap, so that the 900nm laser spot output by the second resonant cavity is reduced and collimated to be incident on the frequency doubling crystal. In this example, the size of the 900nm laser output by the end mirror is about 1.76mm, and the focal length ratio of the first lens and the second lens is about 88, which can reduce the spot size to 50μm so as to be incident on the frequency doubling crystal for nonlinear frequency conversion.

[0057] In a possible implementation, the frequency doubling crystal may be a BBO crystal or an LBO crystal. When the frequency doubling crystal is a BBO crystal, the phase matching angle is set to 26.1°. When the frequency doubling crystal is an LBO crystal, the phase matching angle is set to 22.9°.

[0058] Combine the following Figure 1The specific example of is used to illustrate the generation process of high-power blue solid laser. In this embodiment, a 532nm semiconductor laser output by optical fiber coupling is used as the pump source, which is focused on the titanium-doped sapphire thin crystal through the pump cavity. The titanium-doped sapphire thin crystal is a thin disc with a thickness of 220μm and a diameter of 3mm. Different dielectric films are plated on both sides of the titanium-doped sapphire thin crystal. The side facing the first resonant cavity is plated with an anti-reflection film for 532nm pump laser and 803nm laser, with a transmittance greater than 99.9%. The side facing away from the first resonant cavity is plated with a high-reflection film for 532nm pump laser, with a reflectivity greater than 99.9%. At the same time, the side facing away from the first resonant cavity is also plated with a partially reflective and partially transparent film for 803nm laser, with a transmittance range of 1% to 20%. The titanium-doped sapphire thin crystal is fixed on the diamond crystal by direct bonding technology, and an annular water cooling structure surrounds the diamond crystal to provide heat dissipation for the titanium-doped sapphire thin crystal and the diamond crystal. The side of the end mirror facing the first resonant cavity is coated with a high-reflection film for 803nm laser and a partially reflective and partially transparent film for 900nm laser, and the side facing away from the first resonant cavity is coated with an anti-reflection film for 900nm laser.

[0059] The first resonant cavity is formed by a titanium-doped sapphire thin crystal and an end mirror. When pumped by a 532nm pump laser, the titanium-doped sapphire thin crystal generates an 803nm laser that is incident on the end mirror and is returned along the original path. After being reflected on the titanium-doped sapphire thin crystal, part of the 803nm laser continues to oscillate back and forth in the first resonant cavity, and part of the 803nm laser passes through the titanium-doped sapphire thin crystal and is incident on the diamond crystal. The second resonant cavity is formed by a diamond crystal and an end mirror. When excited by an 803nm laser, the diamond crystal generates a 900nm laser that oscillates back and forth in the second resonant cavity. After being incident on the end mirror, part of the 900nm laser is returned along the original path, and part of the 900nm laser is output through the end mirror. The 900nm laser output from the end mirror is incident on the frequency doubling crystal through the focusing system. When the frequency doubling crystal is BBO, the phase matching angle is adjusted to 26.1°. After passing through the frequency doubling crystal, it is converted into a 450nm blue light laser through nonlinear frequency conversion. The generated 450nm blue light laser is incident on the optical fiber through the coupling system, forming a stable high-power 450nm blue light laser light source that can be used in urological surgery.

[0060] The present invention proposes a high-power 450nm blue solid-state laser that can be used in urological surgery, which has the characteristics of compact structure, simple design and small equipment. The laser can be effectively put into use in medical surgery, providing high-power output to meet clinical needs. Its compact structure not only helps to improve the flexibility of operation, but also facilitates doctors to use it in complex surgical environments, providing a reliable laser solution for urological surgery.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-power blue solid-state laser for urological surgery, characterized in that: include: A pump source, a pump cavity, an annular water cooling structure, a titanium-doped sapphire thin crystal, an end mirror, a diamond crystal, a focusing system, a frequency doubling crystal, a coupling system and an optical fiber, wherein the titanium-doped sapphire thin crystal is fixed to the end face of the diamond crystal, a first resonant cavity is formed between the titanium-doped sapphire thin crystal and the end mirror, and a second resonant cavity is formed between the diamond crystal and the end mirror; Wherein, the pump source is used to output 532nm pump laser, the pump cavity is used to reflect the 532nm pump laser to focus on the titanium-doped sapphire thin crystal; the titanium-doped sapphire thin crystal is used to generate 803nm laser based on the 532nm pump laser, and the 803nm laser oscillates back and forth in the round-trip optical path provided by the first resonant cavity; the diamond crystal is used to form 900nm laser by Raman frequency shift of the 803nm laser generated by the titanium-doped sapphire thin crystal, and the 900nm laser oscillates back and forth in the round-trip optical path provided by the second resonant cavity; the annular water cooling structure is arranged around the diamond crystal to dissipate heat for the diamond crystal and the titanium-doped sapphire crystal; the focusing system is used to focus and align the 900nm laser transmitted from the second resonant cavity to the frequency doubling crystal; the frequency doubling crystal is used to perform nonlinear frequency conversion of the 900nm laser into a 450nm blue light laser; the coupling system couples the generated 450nm blue light laser into the optical fiber.

2. A high-power blue solid-state laser for urological surgery according to claim 1, characterized in that: The titanium-doped sapphire thin slice crystal is fixed on the end face of the diamond crystal by using direct bonding technology. The titanium-doped sapphire thin slice crystal is in the shape of a thin disk with a thickness of 50 μm to 500 μm and a diameter of 3 mm to 15 mm.

3. The high-power blue solid-state laser for urological surgery according to claim 2, characterized in that: The diamond crystal surface processing flatness error is less than 5 μm, the bonding interface tensile strength is greater than 15 Mpa@20°-120°, the bonding surface intercalation thickness is less than 50 nm, and the in-plane residual stress is less than 100 Mpa.

4. The high-power blue solid-state laser for urological surgery according to claim 3, characterized in that: The side of the titanium-doped sapphire thin crystal facing the first resonant cavity is coated with an anti-reflection film for the 532nm pump laser and the 803nm laser, and the transmittance of the anti-reflection film for the 532nm pump laser and the 803nm laser is greater than 99.9%; the side of the titanium-doped sapphire thin crystal facing away from the first resonant cavity is coated with a high-reflection film for the 532nm pump laser and a partially reflective and partially transparent film for the 803nm laser, and the reflectivity of the high-reflection film for the 532nm pump laser is greater than 99.9%, and the transmittance of the partially reflective and partially transparent film for the 803nm laser is in the range of 1% to 20%.

5. The high-power blue solid-state laser for urological surgery according to claim 4, characterized in that: The side of the diamond crystal facing the second resonant cavity is coated with an anti-reflection film for the 803nm laser, and the transmittance of the anti-reflection film for the 803nm laser is greater than 99.9%. The side of the diamond crystal facing away from the second resonant cavity is coated with a high-reflection film for the 803nm laser and the 900nm laser, and the reflectivity of the high-reflection film for the 803nm laser and the 900nm laser is greater than 99.9%.

6. The high-power blue solid-state laser for urological surgery according to claim 5, characterized in that: The length of the diamond crystal along the direction of the second resonant cavity is 5 mm to 10 mm, the length of the diamond crystal along the radial direction of the titanium-doped sapphire thin crystal is 3 mm, and the diamond crystal is made by crystal face cutting.

7. The high-power blue solid-state laser for urological surgery according to claim 1, characterized in that: The end mirror is a plano-concave mirror, the radius of curvature of the concave side of the plano-concave mirror is greater than the length of the second resonant cavity, the concave side of the plano-concave mirror faces the first resonant cavity or the second resonant cavity, and the planar side of the plano-concave mirror faces away from the first resonant cavity or the second resonant cavity.

8. The high-power blue solid-state laser for urological surgery according to claim 7, characterized in that: The concave side of the end mirror is coated with a high-reflection film for 803nm laser, and the reflectivity of the high-reflection film for the 803nm laser is greater than 99.9%. The concave side of the end mirror is also coated with a partially reflective and partially transparent film for 900nm laser, and the transmittance range is 1% to 20%. The flat side of the end mirror is coated with an anti-reflection film for 900nm laser, and the transmittance of the anti-reflection film for the 900nm laser is greater than 99.9%.

9. The high-power blue solid-state laser for urological surgery according to claim 1, characterized in that: The focusing system includes a first lens and a second lens, wherein the first lens is located between the end lens and the second lens, the focal length of the first lens is greater than the focal length of the second lens, and the focal points of the first lens and the second lens are placed so as to overlap.

10. The high-power blue solid-state laser for urological surgery according to claim 1, characterized in that: The frequency doubling crystal is a BBO crystal or an LBO crystal. When the frequency doubling crystal is a BBO crystal, the phase matching angle is set to 26.1°. When the frequency doubling crystal is an LBO crystal, the phase matching angle is set to 22.9°.

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