A side-pumped passively Q-switched laser

Abstract

The application discloses a side-pumped passive Q-switched laser, and relates to the technical field of lasers.The application comprises a base, a pumping assembly, a gain medium, a laser oscillation assembly, a heat dissipation assembly and an output mirror, wherein the gain medium, the laser oscillation assembly and the output mirror are detachably installed on the base, the pumping assembly is arranged on the side of the gain medium perpendicular to the optical axis direction, and the heat dissipation assembly is installed on the base.The application is provided with the heat dissipation device, and the components in the heat dissipation bellow are air-cooled, which, in cooperation with the side erbium glass passive Q-switched mode, can effectively improve the laser energy and the beam quality, and can fully dissipate the heat of the components on the optical axis, so that the service life of the components is prolonged while the quality of the output laser is ensured.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and in particular to a side-pumped passively Q-switched laser. Background Technology

[0002] 1535nm wavelength lasers fall within the communication window and have wide applications in optical communication. Simultaneously, lasers with wavelengths around 1535nm are in a band where the human eye is less sensitive, exhibiting strong penetration through smoke. In particular, 1535nm band miniature Q-switched pulsed lasers, characterized by small size, low power consumption, wide temperature adaptability, high stability, and low cost, have broad application prospects in laser ranging fields such as drones, ranging telescopes, and military applications.

[0003] However, most 1535nm wavelength lasers are currently generated using passive Q-switching with end-pumped erbium glass, resulting in low output laser energy and a large beam divergence angle, making them unsuitable for long-distance measurements and applications. Therefore, to meet the requirements of practical measurements and applications, it is necessary to increase the laser output energy and reduce the laser divergence angle. At the same time, increasing the laser output energy will raise the temperature of components along the optical axis, and components lacking heat dissipation will affect their internal structure after prolonged use, leading to component damage. Summary of the Invention

[0004] The purpose of this invention is to provide a side-pumped passively Q-switched laser to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A side-pumped passively Q-switched laser includes a base, a pump assembly, a gain medium, a laser oscillation assembly, a heat dissipation assembly, and an output mirror. The gain medium, the laser oscillation assembly, and the output mirror are all detachably mounted on the base. The pump assembly is disposed on the side of the gain medium perpendicular to the optical axis. The heat dissipation assembly is mounted on the base.

[0007] The heat dissipation assembly includes a heat dissipation box and a heat dissipation fan. The heat dissipation box is installed on the edge of the base and is composed of an end cover, two fixing plates, an air inlet plate, and an air outlet plate. One end of the fixing plate is fixedly installed on the edge of the base, and the other end is detachably connected to the end cover. The pump assembly is installed on the end cover, and the end cover has a through hole for the laser to pass through corresponding to the laser output position of the pump assembly. The air inlet plate is fixedly installed on the edge of the base away from the output mirror, and the heat dissipation fan passes through the air inlet plate. The air outlet plate is installed on the edge of the base near the output mirror and is in contact with the output mirror. The air outlet plate has a through hole for the laser to pass through corresponding to the optical axis position, and exhaust holes are provided around the through hole of the air outlet plate.

[0008] The end cap is provided with a fixing member for fixing the top position of the output mirror and the laser oscillation component. The fixing member is fixedly connected to the bottom of the end cap by a connecting rod. The contact surface between the fixing member and the output mirror and the laser oscillation component is provided with an upper groove for fitting the output mirror and the laser oscillation component.

[0009] The base is provided with a mounting seat, and the mounting seat is provided with multiple recesses for mounting the gain medium, laser oscillation component and output mirror; a shielding member is provided between the recesses of the mounting seat to prevent dust from adhering to the optical element, and the shielding member is provided with a through hole for the laser to pass through; the mounting seat is an aluminum alloy mounting seat.

[0010] A sealing ring is provided on the contact surface between the shielding component and the gain medium, the laser oscillation component and the output mirror. A sealing ring is also provided on the contact surface between the air outlet plate and the output mirror. The sealing ring is provided with a through hole for the laser to pass through. The sealing ring is a thermally conductive silicone sealing ring. The shielding component is an aluminum alloy component. Multiple heat dissipation fins are provided on the upper surface of the shielding component along the optical axis.

[0011] The pumping assembly includes a laser source and a pump light focusing lens, wherein the laser source, the pump light focusing lens, and the gain medium are arranged sequentially along a direction perpendicular to the optical axis; the laser source is an LD pump laser.

[0012] The laser oscillation assembly includes a Q-switched crystal and a total reflection mirror, both of which are mounted on the optical axis. The Q-switched crystal is located between the output mirror and the gain medium, and the total reflection mirror is located on the side of the gain medium away from the Q-switched crystal.

[0013] The gain medium is Er3+ / Yb3+ co-doped phosphate glass.

[0014] The Q-switched crystal is a cobalt-doped spinel crystal.

[0015] The beneficial effects of this invention are:

[0016] ① By adding a heat dissipation device, the components inside the heat dissipation box are cooled by air. Combined with the passive Q-switching method of the side erbium glass, the laser energy and beam quality can be effectively improved, and the components on the optical axis can be fully cooled, thereby extending the service life of the components while ensuring the output laser quality.

[0017] ② The components and the base are connected by grooves for easy disassembly. Components can be installed or removed according to actual needs, which facilitates cleaning of the components and avoids dust accumulation on the components due to long-term use, which may affect the laser output quality. Attached Figure Description

[0018] Figure 1This is a side sectional view of the present invention;

[0019] Figure 2 This is a front view of the air intake plate in this invention;

[0020] Figure 3 This is a front view of the air outlet plate in this invention.

[0021] In the diagram: 1. Base; 2. Gain medium; 3. Output mirror; 4. Cooling fan; 5. End cap; 6. Mounting plate; 7. Inlet plate; 8. Outlet plate; 9. Exhaust port; 10. Fixing component; 11. Shielding component; 12. Laser source; 13. Pump light focusing lens; 14. Q-switched crystal; 15. Total reflection mirror; 16. Mounting base; 17. Sealing ring. Detailed Implementation

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0023] Please see Figures 1-3 This invention provides a side-pumped passively Q-switched laser.

[0024] like Figure 1 As shown, a side-pumped passively Q-switched laser includes a base 1, a pump assembly, a gain medium 2, a laser oscillation assembly, a heat dissipation assembly, and an output mirror 3. The gain medium 2, the laser oscillation assembly, and the output mirror 3 are all detachably mounted on the base 1. The pump assembly is located on the side of the gain medium 2 perpendicular to the optical axis. The heat dissipation assembly is mounted on the base 1.

[0025] The heat dissipation assembly includes a heat dissipation box and a heat dissipation fan 4; the heat dissipation box is installed on the edge of the base 1 and is composed of an end cover 5, two fixing plates 6, an air inlet plate 7 and an air outlet plate 8; one end of the fixing plate 6 is fixedly installed on the edge of the base 1, and the other end is detachably connected to the end cover 5; the pump assembly is installed on the end cover 5, and the end cover 5 is provided with a through hole for the laser to pass through at the laser output position of the pump assembly.

[0026] like Figure 2 As shown, the air intake plate 7 is fixedly installed on the edge of the base 1 away from the output mirror 3, and the cooling fan 4 is installed on the air intake plate 7; in order to prevent workers from accidentally touching the cooling fan 4 and getting injured when using the present invention, a protective fence can be installed on the outside of the cooling fan 4.

[0027] like Figure 3 As shown, the vent plate 8 is installed on the edge of the base 1 near the output mirror 3 and is in contact with the output mirror 3. The vent plate 8 has a through hole for the laser to pass through at the position corresponding to the optical axis. The vent hole 9 is provided around the through hole of the vent plate 8.

[0028] The cooling box and the base 1 enclose a semi-enclosed space around the optical axis. Cool air is delivered into this semi-enclosed space by the cooling fan 4. The cool air passes through the gaps between the optical components and the inner wall of the cooling box, and then is discharged from the air outlet of the air outlet plate 8, thereby achieving the effect of air cooling for the optical components on the optical axis.

[0029] The detachable end cap 5, in conjunction with the lower groove, makes the assembly and disassembly of the optical components on the optical axis very simple, making it very convenient for staff to assemble or clean and replace the optical components on the optical axis, thus reducing the installation and maintenance costs of this invention.

[0030] The end cap 5 is provided with a fixing member 10 for fixing the top position of the output mirror 3 and the laser oscillation component. The fixing member 10 is fixedly connected to the bottom of the end cap 5 by a connecting rod. The contact surface between the fixing member and the output mirror 3 and the laser oscillation component is provided with an upper groove for fitting the output mirror 3 and the laser oscillation component.

[0031] After the optical elements on the optical axis are installed on the mounting base 16, the upper groove will cooperate with the lower groove on the mounting base 16 to press the output mirror 3, Q-switched crystal 14 and total reflection mirror 15 on the optical axis, ensuring that the placement angle of the output mirror 3, Q-switched crystal 14 and total reflection mirror 15 is always perpendicular to the optical axis, thereby ensuring that the oscillation and output direction of the laser in the resonant cavity is always consistent with the optical axis direction.

[0032] The base 1 is provided with a mounting base 16, which has multiple recesses for mounting the gain medium 2, the laser oscillation assembly and the output mirror 3. A shielding member 11 is provided between the recesses of the mounting base 16 to prevent dust from adhering to the optical elements. The shielding member 11 has a through hole for the laser to pass through. The mounting base 16 is an aluminum alloy mounting base.

[0033] The recessed groove facilitates the assembly of optical components onto the mounting base 16. The shape and size of the groove can be pre-set according to the dimensions of different optical components to ensure that the center of each optical component is aligned with the optical axis after installation. When the optical components become dusty after long-term use and affect the output laser quality, the optical components can be removed from the groove and cleaned to further ensure the output laser quality. At the same time, the mounting base 16 is made of aluminum alloy with good thermal conductivity, which can accelerate the conduction of heat from the optical components and provide better heat dissipation for the optical components on the optical axis.

[0034] A sealing ring 17 is provided on the contact surface between the shielding member 11 and the gain medium 2, the laser oscillation component and the output mirror 3. A sealing ring 17 is also provided on the contact surface between the air outlet plate 8 and the output mirror 3. The sealing ring 17 is provided with a through hole for the laser to pass through. The sealing ring 17 is a thermally conductive silicone sealing ring.

[0035] After the optical element is installed in the lower groove, the elastic sealing ring 17 will be tightly adsorbed on the contact surface with the optical element, thus forming a sealed space around the optical axis of the optical element. This further prevents dust and other debris from adhering to the area of ​​the optical element facing the optical axis, thereby reducing the impact of dust and other debris on the light transmission in the optical element and ensuring the quality of the output laser. At the same time, the sealing ring 17 is made of silicone, which has good cold and heat resistance and can be used for a long time in an environment of -60°C to +250°C. The thermal conductivity of commonly available silicone gaskets can reach 1.2W / (m*k), which can ensure that the sealing ring can quickly conduct the heat of the part of the optical element near the optical axis to the edge or shielding part 11.

[0036] The shielding component 11 is made of aluminum alloy, and the upper surface of the shielding component 11 is provided with multiple heat dissipation fins along the optical axis. The aluminum alloy shielding component 11 has good thermal conductivity. At the same time, the fins on the shielding component 11 can increase the contact area between the cold air in the heat dissipation box and the shielding component 11, further increasing the heat dissipation efficiency of the shielding component 11. When the shielding component 11 cooperates with the sealing ring 17, the heat accumulated on the optical element near the optical axis can be quickly dissipated through contact conduction, thereby further ensuring the heat dissipation effect of the present invention on the optical element.

[0037] The pumping assembly includes a laser source 12 and a pump light focusing lens 13, wherein the laser source 12, the pump light focusing lens 13 and the gain medium 2 are arranged sequentially along a direction perpendicular to the optical axis; the laser source 12 is an LD pump laser, which is an LD pulse laser array with a center wavelength of 940nm and a power greater than 50W.

[0038] Since the gain medium 2 can provide a large heat dissipation area when side-pumping, the pump intensity of side-pumping can be increased, and a larger output energy can be obtained. In addition, the pump light focusing lens 13 makes the pump light more uniformly incident into the gain medium 2 after focusing and shaping, which increases the mode volume of the impact radiation of the gain medium 2, and can also improve the laser energy and beam quality.

[0039] The pump light focusing lens 13 is not limited to a single lens; multiple lenses can be selected to form a lens group according to actual needs, thereby improving the focusing efficiency of the pump light.

[0040] The laser oscillation assembly includes a Q-switched crystal 14 and a total reflection mirror 15, both mounted on the optical axis. The Q-switched crystal 14 is located between the output mirror 3 and the gain medium 2, while the total reflection mirror 15 is located on the side of the gain medium 2 furthest from the Q-switched crystal 14. After coating, the output mirror 3 and the total reflection mirror 15 form a resonant cavity with a center wavelength of 1535 nm and a linewidth of 20 nm.

[0041] The gain medium 2 is an Er3+ / Yb3+ co-doped phosphate glass. Erbium-doped (Er3+) phosphate glass itself has good chemical and thermal stability; while introducing ytterbium (Yb3+) ions into it to make an erbium-ytterbium co-doped phosphate glass as the gain medium 2 can greatly improve the amplification performance of the gain medium 2.

[0042] The Q-switched crystal 14 is a cobalt-doped spinel crystal.

[0043] The working principle of this invention is as follows: Before use, the output mirror 3, Q-switching crystal 14, gain medium 2 and total reflection mirror 15 are respectively installed in the corresponding grooves 10, and then the end cap 5 is assembled on the fixing plate 6 to complete the component assembly of this invention.

[0044] When this invention is in operation, the cooling fan 4 is first started to begin air cooling of the output mirror 3, Q-switching crystal 14, gain medium 2 and total reflection mirror 15 on the optical axis;

[0045] Then the LD pump laser is turned on, generating a 940nm laser that irradiates the pump light focusing lens 13. The focused pump light then irradiates the gain medium 2, causing the gain medium 2 to generate 1535nm excitation light.

[0046] The excitation light generated by the gain medium 2 reaches the output mirror 3. The output mirror 3 and the total reflection mirror 15 form a parallel resonant cavity, which causes the 1535nm laser to oscillate back and forth in the cavity, exciting the gain medium 2 to form a 1535nm laser, thereby gradually increasing the power of the 1535nm laser in the cavity.

[0047] When the laser power of 1535nm reaches the threshold of the Q-switched crystal 14, it will transmit through the Q-switched crystal 14 and the output mirror 3, and emit a Q-switched pulse laser.

[0048] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A side-pumped passively Q-switched laser, characterized in that: The laser includes a base (1), a pump assembly, a gain medium (2), a laser oscillation assembly, a heat dissipation assembly, and an output mirror (3). The gain medium (2), the laser oscillation assembly, and the output mirror (3) are all detachably mounted on the base. The pump assembly is located on the side of the gain medium (2) perpendicular to the optical axis. The heat dissipation assembly is mounted on the base (1). The heat dissipation assembly includes a heat dissipation box and a heat dissipation fan (4); the heat dissipation box is installed on the edge of the base (1) and is composed of an end cover (5), two fixing plates (6), an air inlet plate (7) and an air outlet plate (8); one end of the fixing plate (6) is fixedly installed on the edge of the base (1), and the other end is detachably connected to the end cover (5); the pump assembly is installed on the end cover (5), and the end cover (5) is provided with a through hole for the laser to pass through corresponding to the laser output position of the pump assembly; the air inlet plate (7) is fixedly installed on the edge of the base (1) away from the output mirror (3), and the heat dissipation fan (4) passes through the air inlet plate (7); the air outlet plate (8) is fixedly installed on the edge of the base (1) near the output mirror (3), and the air outlet plate (8) is provided with a through hole for the laser to pass through, and exhaust holes (9) are provided around the through hole of the air outlet plate (8); The base (1) is provided with a mounting base (16), and the mounting base is provided with a groove for mounting the gain medium (2), the laser oscillation component and the output mirror (3), and there are multiple grooves; between the grooves of the mounting base (16) are shielding members (11) to prevent dust from adhering to the optical components, and the shielding members (11) are provided with through holes for the laser to pass through; the mounting base (16) is an aluminum alloy mounting base; A sealing ring (17) is provided on the contact surface between the shielding component (11) and the gain medium (2), the laser oscillation component and the output mirror (3). A sealing ring (17) is also provided on the contact surface between the air outlet plate (8) and the output mirror (3). A through hole for the laser to pass through is provided on the sealing ring (17). The sealing ring (17) is a thermally conductive silicone sealing ring. The shielding component (11) is an aluminum alloy part. Multiple heat dissipation fins are provided on the upper surface of the shielding component (11) along the optical axis.

2. The side-pumped passively Q-switched laser according to claim 1, characterized in that: The end cap (5) is provided with a fixing member (10) for fixing the top position of the output mirror (3) and the laser oscillation component. The fixing member (10) is fixedly connected to the bottom of the end cap (5) by a connecting rod. The contact surface between the fixing member and the output mirror (3) and the laser oscillation component is provided with an upper groove for fitting the output mirror (3) and the laser oscillation component.

3. A side-pumped passively Q-switched laser according to claim 1, characterized in that: The pumping assembly includes a laser source (12) and a pump light focusing lens (13). The laser source (12), the pump light focusing lens (13), and the gain medium (2) are arranged sequentially along a direction perpendicular to the optical axis. The laser source (12) is an LD pump laser.

4. A side-pumped passively Q-switched laser according to claim 1, characterized in that: The laser oscillation assembly includes a Q-switched crystal (14) and a total reflection mirror (15), both of which are mounted on the optical axis. The Q-switched crystal (14) is located between the output mirror (3) and the gain medium (2), and the total reflection mirror (15) is located on the side of the gain medium (2) away from the Q-switched crystal (14).

5. A side-pumped passively Q-switched laser according to claim 1, characterized in that: The gain medium (2) is Er3+ / Yb3+ co-doped phosphate glass.

6. A side-pumped passively Q-switched laser according to claim 4, characterized in that: The Q-switched crystal (14) is a cobalt-doped spinel crystal.

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