Double-end double-pump acousto-optic Q-switched laser

Abstract

The utility model provides a double-end double-pumping acousto-optic Q-switched laser, which comprises a laser crystal and four pumping sources, every two pumping sources are respectively arranged at two ends of the laser crystal, and a pumping lens group, a pumping light reverse isolator and a dichroic mirror are sequentially arranged between each pumping source and the laser crystal. The laser further comprises an acousto-optic Q switch and an output mirror. Pumping laser sequentially passes through the pumping lens group and the dichroic mirror and is focused into the laser crystal, most of the pumping laser is absorbed by the laser crystal, and the unabsorbed pumping laser passes through the dichroic mirror and the pumping light reverse isolator respectively and is isolated from the pumping source in a reflection mode. According to the double-end double-pumping acousto-optic Q-switched laser provided by the utility model, the absorption rate of the laser crystal to the pumping laser is improved, and the four pumping sources all use the pumping laser with smaller power, so that the heat dissipation of the laser crystal is very facilitated, and meanwhile, the safe output power of the laser is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of lasers, in particular to a double-ended double-pumped acousto-optic Q-switched laser. Background Art

[0002] End-pumped acousto-optic Q-switched laser is a major precision processing laser that can be used in 3C precision marking, glass drilling, PCB depaneling, ceramic material scribing, hard and brittle material cutting, etc. At present, the pumping method used by this laser is mainly to use a high-power pump module to pump the Nd:YVO4 crystal from one end of the Nd:YVO4 crystal. This pumping method causes most of the pump light to be absorbed near the end of the Nd:YVO4 crystal, which is very unfavorable for heat dissipation. In addition, the fracture threshold of the Nd:YVO4 crystal is very low. This pumping method also makes the Nd:YVO4 crystal very easy to explode, which ultimately makes it difficult to further increase the safe output power of this laser. Utility Model Content

[0003] The purpose of the utility model is to provide a double-ended double-pumped acousto-optic Q-switched laser to solve the problem that the pumping method of the current end-pumped acousto-optic Q-switched laser is not conducive to heat dissipation, making the Nd:YVO4 crystal very easy to explode, and the laser's safe output power is difficult to increase. The specific technical solution is as follows:

[0004] A double-ended double-pumped acousto-optic Q-switched laser, comprising a laser crystal, a first pump source, a second pump source, a third pump source and a fourth pump source, wherein the first pump source and the third pump source are located outside one end of the laser crystal, and the second pump source and the fourth pump source are located outside the other end of the laser crystal;

[0005] The laser also includes a pump lens group, a pump reverse isolator and a dichroic mirror between each of the pump sources and the laser crystal;

[0006] The laser also includes a two-color matching lens, an acousto-optic Q switch and an output mirror.

[0007] Further, the first pump source and the second pump source are arranged at two ends of the laser crystal relatively to each other, and between the first pump source and the laser crystal are sequentially a first pump lens group, a first pump reverse isolator, a first 45° dichroic mirror and a dichroic matching mirror, and between the second pump source and the laser crystal are sequentially a second pump lens group, a second pump reverse isolator and a second 45° dichroic mirror;

[0008] The third pump source is in a direction perpendicular to the first pump source and directly faces the first 45° dichroic mirror, and between the third pump source and the first 45° dichroic mirror are a third pump lens group, a third pump reverse isolator, and a 0° dichroic mirror in sequence;

[0009] The fourth pump source is in a direction perpendicular to the second pump source and directly opposite to the second 45° dichroic mirror. Between the fourth pump source and the second 45° dichroic mirror are a fourth pump lens group, a fourth pump reverse isolator, and a third 45° dichroic mirror.

[0010] Furthermore, the acousto-optic Q switch and the output mirror are in the direction of the reflected light path of the third 45° dichroic mirror and are located on the side of the laser crystal.

[0011] Furthermore, the first pump source, the second pump source, the third pump source and the fourth pump source are polarization-maintaining fiber-coupled output semiconductor lasers, with an output wavelength of 808nm or 878.6nm, an output fiber core diameter of 200um or 400um, and a numerical aperture of 0.22.

[0012] Furthermore, the first 45° dichroic mirror and the second 45° dichroic mirror are tilted in opposite directions, and both the first 45° dichroic mirror and the second 45° dichroic mirror are coated with an 808nm or 878.6nm anti-reflection film on one side and an 808nm or 878.6nm high-reflection film and a 1064nm high-reflection film on the other side.

[0013] Furthermore, the third 45° dichroic mirror is tilted in the opposite direction to the second 45° dichroic mirror, one side of the third 45° dichroic mirror is coated with an 808nm or 878.6nm anti-reflection film, and the other side is coated with a 1064nm high-reflection film; one side of the 0° dichroic mirror is coated with an 808nm or 878.6nm anti-reflection film, and the other side is coated with a 1064nm high-reflection film.

[0014] Furthermore, each of the pump lens groups is composed of two plano-convex lenses, the focal length ratio of the two plano-convex lenses is 1:3 to 1:6, and each of the plano-convex lenses is coated with an 808nm or 878.6nm anti-reflection film on both sides.

[0015] Furthermore, the pump light reflection isolators are located between the two plano-convex lenses of the corresponding pump lens group, and each of the pump light reflection isolators is composed of a Brewster polarizer and a 1 / 4 wave plate, the Brewster polarizer is coated with an 808nm or 878.6nm anti-reflection film on one side and an 808nm or 878.6nm high-reflection film on the other side, and the 1 / 4 wave plate is coated with an 808nm or 878.6nm anti-reflection film on one side and an 808nm or 878.6nm high-reflection film on the other side.

[0016] Furthermore, the acousto-optic Q switch has a light aperture of 1 to 6 mm, an operating wavelength of 1030 to 1064 nm, and an operating frequency of 27 MHz to 40.68 MHz.

[0017] Furthermore, the output mirror is a 0° infrared output mirror, and the infrared transmittance of the 0° infrared output mirror is 30% to 70%.

[0018] The double-ended double-pumped acousto-optic Q-switched laser provided by the utility model has the following beneficial effects:

[0019] The utility model provides a double-ended double-pumped acousto-optic Q-switched laser, in which each end face of the laser crystal is pumped by two relatively low-power pump sources, which is very beneficial to the heat dissipation of the laser crystal and greatly improves the safe output power of the laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The utility model provides a double-ended double-pumped acousto-optic Q-switched laser.

[0021] Figure numerals: 1, 10, 17, 20 - pump source; 2, 8, 15, 18 - pump lens group; 3, 9, 16, 19 - pump reverse isolator; 5 - two-color matching lens; 6 - Nd:YVO4 crystal; 4, 7, 11 - 45° two-color mirror; 14 - 0° two-color mirror; 12 - acousto-optic Q switch; 13 - 0° infrared total reflection mirror. DETAILED DESCRIPTION

[0022] The following will be combined with the accompanying drawings provided by the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. According to the following description, the advantages and features of the utility model will be clearer. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the utility model.

[0023] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connection" and "connected" should be interpreted in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] In the description of the present invention, terms such as "upper", "lower", "left", "right", "front", "back", "center", "horizontal", "vertical", "top", "bottom", "inside" and "outside" and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of description and simplification of operation, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0025] Embodiment: This embodiment provides a double-ended double-pumped acousto-optic Q-switched laser. Figure 1 As shown, the laser includes a laser crystal 6 and four pump sources, and the four pump sources are arranged in pairs at the outer sides of the two ends of the laser crystal 6; the first pump source 1 and the second pump source 10 are at the two ends of the laser crystal 6 and are arranged opposite to each other, the third pump source 17 and the first pump source 1 are at the same end of the laser crystal 6, and the pump light output direction of the third pump source 17 is perpendicular to the pump light output direction of the first pump source 1, and the fourth pump source 20 is at the same end of the laser crystal 6 as the second pump source 10, and the pump light output direction of the fourth pump source 20 is perpendicular to the pump light output direction of the second pump source 10.

[0026] In the double-ended double-pumped acousto-optic Q-switched laser provided in this embodiment, both end faces of the laser crystal are pumped by two relatively low-power pump sources, which is very beneficial to the heat dissipation of the laser crystal and greatly improves the safe output power of the laser.

[0027] As a specific implementation of the first pump source 1 , a first pump lens group 2 , a first pump light reverse isolator 3 , a first 45° dichroic mirror 4 , and a dichroic matching lens 5 are sequentially arranged between the first pump source 1 and the laser crystal 6 .

[0028] As a specific implementation of the second pump source 10, a second pump lens group 8, a second pump light reverse isolator 9 and a second 45° dichroic mirror 7 are sequentially arranged between the second pump source 10 and the laser crystal 6. The first 45° dichroic mirror 4 and the second 45° dichroic mirror 7 have opposite inclination directions.

[0029] As a specific implementation of the third pump source 17, the third pump source 17 is directly opposite to the reflecting surface of the first 45° dichroic mirror 4, and a third pump lens group 15, a third pump light reverse isolator 16, and a 0° dichroic mirror 14 are sequentially arranged between the third pump source 17 and the first 45° dichroic mirror 4.

[0030] As a specific implementation of the fourth pump source 20, the fourth pump source 20 is directly opposite to the reflection surface of the second 45° dichroic mirror 7, and a fourth pump lens group 18, a fourth pump light reverse isolator 19, and a third 45° dichroic mirror 11 are sequentially arranged between the fourth pump source 20 and the second 45° dichroic mirror 7. The third 45° dichroic mirror 11 is tilted in the opposite direction to the second 45° dichroic mirror 7. There are also an acousto-optic Q switch 12 and an output mirror 13 in the direction of the reflected light path of the third 45° dichroic mirror 11.

[0031] The first 45° dichroic mirror 4 , the laser crystal 6 , the second 45° dichroic mirror 7 , the third 45° dichroic mirror 11 , the acousto-optic Q switch 12 and the output mirror 13 constitute a resonant cavity.

[0032] Optionally, the first pump source 1, the second pump source 10, the third pump source 17 and the fourth pump source 20 are all polarization-maintaining fiber-coupled output semiconductor lasers, the fiber numerical aperture of the semiconductor laser is 0.22, the fiber core diameter is 200um or 400um, and the output wavelength is 808nm or 878.6nm.

[0033] Optionally, the first pump lens group 2, the second pump lens group 8, the third pump lens group 15 and the fourth pump lens group 18 are all composed of two plano-convex lenses, the focal length ratio of the two plano-convex lenses is 1:3 to 1:6, and the two surfaces of the two plano-convex lenses are coated with 808nm or 878.6nm anti-reflection film. The pump lens group is used to shape the pump source laser to match the base film oscillation light in the laser resonant cavity.

[0034] Optionally, the first pump light reverse isolator 3, the second pump light reverse isolator 9, the third pump light reverse isolator 16 and the fourth pump light reverse isolator 19 are all composed of a Brewster polarizer and a 1 / 4 wave plate, the Brewster polarizer is coated with an 808nm or 878.6nm anti-reflection film on one side and an 808nm or 878.6nm high-reflection film on the other side, and the 1 / 4 wave plate is coated with an 808nm or 878.6nm anti-reflection film on one side and an 808nm or 878.6nm high-reflection film on the other side. The above-mentioned pump light reverse isolators are all located between the two plano-convex lenses of the corresponding pump lens group. The pump light reverse isolator is used to isolate pump sources that output pump light in reverse directions from each other, the first pump source 1 and the second pump source 10 are isolated from each other, and the third pump source 17 and the fourth pump source 20 are isolated from each other.

[0035] Optionally, the first 45° dichroic mirror 4 and the second 45° dichroic mirror 7 are double-plane dichroic mirrors, one side close to the pump source is coated with an 808nm or 878.6nm anti-reflection film, and the other side is coated with an 808nm or 878.6nm high-reflection film and a 1064nm high-reflection film; the third 45° dichroic mirror 11 is a double-plane dichroic mirror, one side close to the pump source is coated with an 808nm or 878.6nm anti-reflection film, and the other side is coated with a 1064nm high-reflection film; the 0° dichroic mirror 14 is a double-plane dichroic mirror or a plano-convex dichroic mirror, one side close to the pump source is coated with an 808nm or 878.6nm anti-reflection film, and the other side is coated with a 1064nm high-reflection film.

[0036] Optionally, the two-color matching lens 5 is a plano-convex lens with a focal length of 70 mm, double-sidedly coated with 808 nm, 878.6 nm and 1064 nm anti-reflection modes, and is placed 1 to 2 cm away from the end face of the laser crystal 6 .

[0037] Optionally, the size of the laser crystal 6 is 4 mm×4 mm×60 mm, and the doping concentration of neodymium ions is 0.25% at.

[0038] Optionally, the aperture of the acousto-optic Q switch 12 is 1-6 mm, its operating wavelength is 1030-1064 nm, and its operating frequency is 27-40.68 MHz.

[0039] Optionally, the output mirror 13 is a 0° infrared output mirror, which is a double-plane monochromatic mirror, and its infrared transmittance is 30% to 70%.

[0040] The working process and working principle of the above laser are described in detail below through a set of specific numerical values.

[0041] Among them, the four pump sources all output 60W horizontally polarized pump light, the core diameter of the output fiber is 400um, the numerical aperture is 0.22, the output wavelength of the first pump source 1 and the second pump source 10 is 808nm, and the output wavelength of the third pump source 17 and the fourth pump source 20 is 878.6nm. The plano-convex lenses in the first pump lens group 2 and the second pump lens group 7 are coated with 808nm anti-reflection film on both sides, and the focal length of the first plano-convex lens in the first pump lens group 2 and the second pump lens group 7 is 20mm, the focal length of the second plano-convex lens is 60mm, and the focal length ratio is 1:3; the plano-convex lenses in the third pump lens group 15 and the fourth pump lens group 18 are coated with 878.6nm anti-reflection film on both sides, and the focal length of the first plano-convex lens in the third pump lens group 15 and the fourth pump lens group 18 is 20mm, the focal length of the second plano-convex lens is 75mm, and the focal length ratio is 1:3.75. The Brewster polarizer and the quarter wave plate in the first pump light reverse isolator 3 and the second pump light reverse isolator 9 are coated with 808nm anti-reflection film on one side and 878.6nm high reflection film on the other side. The Brewster polarizer and the quarter wave plate in the third pump light reverse isolator 16 and the fourth pump light reverse isolator 19 are coated with 878.6nm anti-reflection film on one side and 808nm high reflection film on the other side. The first 45° dichroic mirror 4 and the second 45° dichroic mirror 7 are coated with 808nm anti-reflection film on one side and 878.6nm and 1064nm high reflection film on the other side; the third 45° dichroic mirror 11 is coated with 878.6nm anti-reflection film on one side and 1064nm high reflection film on the other side; the 0° dichroic mirror 14 is coated with 878.6nm anti-reflection film on one side and 1064nm high reflection film on the other side. The two-color matching lens 5 is coated with 808nm, 878.6nm and 1064nm anti-reflection modes on both sides. The aperture of the acousto-optic Q switch is 3mm, the working wavelength is 1064nm, the ultrasonic frequency is 40.68MHz, and the modulation frequency is 100KHz. The transmittance of the output mirror 13 is 50%.

[0042] First, only ultrasonic waves are loaded on the acousto-optic Q switch 12, and the first-order diffraction generated by the acousto-optic Q switch 12 is used to deflect the spontaneous radiation fluorescence out of the cavity, so that the resonant cavity is in a high-loss state to suppress stimulated radiation so that no fundamental mode oscillation light is generated in the resonant cavity; at this time, the pump light output by the first pump source 1 and the third pump source 17 is shaped by the first pump lens group 2 and the third pump lens group 15 respectively, and then passes through the first 45° dichroic mirror 4 and the 0° dichroic mirror 14 respectively, and finally is focused to the distance Nd:YV by the dichroic matching lens 5. At about 5-7mm and 15-21mm inside the left end face of the Nd:YVO4 crystal 6; at the same time, the pump light output by the second pump source 10 and the fourth pump source 20 is shaped by the second pump lens group 8 and the fourth pump lens group 18 respectively, and then respectively focused by the second 45° dichroic mirror 7 and the third 45° dichroic mirror 11 to the position about 5-7mm and 15-21mm from the right end face of the Nd:YVO4 crystal 6, so that more than 85% of the pump light is absorbed by the Nd:YVO4 crystal 6 to complete energy storage. The small part of the unabsorbed pump light output by the four pump sources is isolated from the pump source in the form of reflection by the first 45° dichroic mirror 4, the second 45° dichroic mirror 7, the third 45° dichroic mirror 11 and the four pump light reverse isolators.

[0043] Secondly, after the Nd:YVO4 crystal 6 completes energy storage, the acousto-optic Q switch 12 is loaded with ultrasonic waves and a modulation signal at the same time, so that the acousto-optic Q switch 12 is in a switching state of 1st order diffraction-0th order diffraction-1st order diffraction. At this time, the loss of the resonant cavity is modulated to show a periodic change of high loss-low loss-high loss, and the change frequency is equal to the modulation frequency. When the resonant cavity is in a low-loss state, the fundamental mode oscillation light with a wavelength of 1064nm generated in the resonant cavity due to stimulated radiation is output to the outside of the cavity through the output mirror 13. When the modulation frequency is 100KHz, the output frequency is 100KHz, the power is 150W, the pulse width is 10ns, M2<1.5, and the wavelength is 1064nm. Pulse laser.

[0044] Those skilled in the art should understand that the present invention can be implemented in many other specific forms without departing from the spirit and scope of the present invention. Based on the embodiments of the present invention, any changes and modifications made by ordinary technicians in the field of the present invention according to the above disclosure are within the scope of protection of the claims.

Claims

1. A double-ended double-pumped acousto-optic Q-switched laser, characterized in that: The invention comprises a laser crystal, a first pump source, a second pump source, a third pump source and a fourth pump source, wherein the first pump source and the third pump source are located outside one end of the laser crystal, and the second pump source and the fourth pump source are located outside the other end of the laser crystal; The laser also includes a pump lens group, a pump reverse isolator and a dichroic mirror between each of the pump sources and the laser crystal; The laser also includes a two-color matching lens, an acousto-optic Q switch and an output mirror.

2. The double-ended double-pumped acousto-optic Q-switched laser according to claim 1, characterized in that: The first pump source and the second pump source are arranged at two ends of the laser crystal relatively to each other, and between the first pump source and the laser crystal are sequentially a first pump lens group, a first pump reverse isolator, a first 45° dichroic mirror and a dichroic matching mirror, and between the second pump source and the laser crystal are sequentially a second pump lens group, a second pump reverse isolator and a second 45° dichroic mirror; The third pump source is in a direction perpendicular to the first pump source and directly faces the first 45° dichroic mirror, and between the third pump source and the first 45° dichroic mirror are a third pump lens group, a third pump reverse isolator, and a 0° dichroic mirror in sequence; The fourth pump source is in a direction perpendicular to the second pump source and directly opposite to the second 45° dichroic mirror. Between the fourth pump source and the second 45° dichroic mirror are a fourth pump lens group, a fourth pump reverse isolator, and a third 45° dichroic mirror.

3. The double-ended double-pumped acousto-optic Q-switched laser according to claim 2, characterized in that: The acousto-optic Q switch and the output mirror are in the direction of the reflected light path of the third 45° dichroic mirror and are located on the side of the laser crystal.

4. The double-ended double-pumped acousto-optic Q-switched laser according to claim 2, characterized in that: The first pump source, the second pump source, the third pump source and the fourth pump source are polarization-maintaining fiber-coupled output semiconductor lasers, with an output wavelength of 808nm or 878.6nm, an output fiber core diameter of 200um or 400um, and a numerical aperture of 0.

22.

5. The double-ended double-pumped acousto-optic Q-switched laser according to claim 4, characterized in that: The first 45° dichroic mirror and the second 45° dichroic mirror are tilted in opposite directions. The first 45° dichroic mirror and the second 45° dichroic mirror are both coated with an 808nm or 878.6nm anti-reflection film on one side and an 808nm or 878.6nm high-reflection film and a 1064nm high-reflection film on the other side.

6. The double-ended double-pumped acousto-optic Q-switched laser according to claim 4, characterized in that: The third 45° dichroic mirror is tilted in the opposite direction to the second 45° dichroic mirror. One side of the third 45° dichroic mirror is coated with an 808nm or 878.6nm anti-reflection film, and the other side is coated with a 1064nm high-reflection film; one side of the 0° dichroic mirror is coated with an 808nm or 878.6nm anti-reflection film, and the other side is coated with a 1064nm high-reflection film.

7. The double-ended double-pumped acousto-optic Q-switched laser according to claim 4, characterized in that: Each of the pump lens groups is composed of two plano-convex lenses, the focal length ratio of the two plano-convex lenses is 1:3-1:6, and each of the plano-convex lenses is coated with 808nm or 878.6nm anti-reflection film on both sides.

8. The double-ended double-pumped acousto-optic Q-switched laser according to claim 4, characterized in that: The pump light reflection isolators are all located between the two plano-convex lenses of the corresponding pump lens group, and each of the pump light reflection isolators is composed of a Brewster polarizer and a 1 / 4 wave plate. The Brewster polarizers are coated with an 808nm or 878.6nm anti-reflection film on one side and an 808nm or 878.6nm high-reflection film on the other side. The 1 / 4 wave plates are coated with an 808nm or 878.6nm anti-reflection film on one side and an 808nm or 878.6nm high-reflection film on the other side.

9. The double-ended double-pumped acousto-optic Q-switched laser according to any one of claims 1 to 8, characterized in that: The acousto-optic Q switch has a light aperture of 1-6 mm, an operating wavelength of 1030-1064 nm, and an operating frequency of 27 MHz-40.68 MHz.

10. The double-ended double-pumped acousto-optic Q-switched laser according to any one of claims 1 to 8, characterized in that: The output mirror is a 0° infrared output mirror, and the infrared transmittance of the 0° infrared output mirror is 30% to 70%.

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