A temperature-controllable and high-pressure-resistant alkali metal gain generating device

Abstract

The present invention belongs to the technical field of alkali metal lasers, and particularly relates to a temperature-controllable and high-pressure-resistant alkali metal gain generating device. The device includes a gain cell body, a laser window, and a heating device. A main gas channel is provided inside the gain cell body. Four laser windows are circumferentially arranged on the side wall of the gain cell body, and a plurality of air curtain grooves are respectively located above each laser window. The air curtain grooves are used to blow inert protective gas onto the inner surface of the laser window. The heating device is arranged inside the side wall of the gain cell body and is disposed around the main gas channel. Through the optimized design of the structures of the gain cell body and the laser window, the present invention not only provides the pressure and temperature conditions for the gain region to ensure the stable operation of the alkali metal laser, but also greatly guarantees the fluid uniformity, thereby ensuring the quality of the output laser beam.

Description

Technical Field

[0001] The present invention belongs to the technical field of alkali metal lasers, and particularly relates to a temperature-controllable and high-pressure-resistant alkali metal gain generating device. Background Art

[0002] The gain cell of a flow-type alkali metal laser is a key component of the flow-type alkali metal laser, where the pump light, the output laser, and the alkali metal atoms interact. To ensure the efficient and stable operation of the alkali metal laser, the gain cell needs to maintain the alkali metal vapor therein at an appropriate pressure, temperature, and flow field uniformity.

[0003] Currently, the inner surface of the window of the known gain cell of the flow-type alkali metal laser is not flush with the inner surface of the flow channel. When the air flow passes through the uneven area on the surface, turbulence and vortex structures will be formed, resulting in uneven flow field. This non-uniformity will lead to a decrease in the quality of the laser beam, restricting the application range of the flow-type alkali metal laser. In addition, for higher power cases, the window on the gain cell is usually larger, and the temperature at the center and edge of the window is prone to be uneven, and the phenomenon of alkali metal condensation occurs. Moreover, the flow-type alkali metal laser usually operates at a relatively high air pressure. To withstand sufficient air pressure, the structure of the gain cell needs to have sufficient strength, which usually conflicts with the requirement of weight reduction. The known flow-type alkali metal lasers have not been fully optimized considering both strength and weight reduction. Summary of the Invention

[0004] Aiming at the above problems, the purpose of the present invention is to provide a temperature-controllable and high-pressure-resistant alkali metal gain generating device to solve the problems of the decrease in the quality of the laser beam caused by the uneven air flow field and the alkali metal condensation phenomenon caused by the uneven temperature at the window of the gain cell.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A temperature-controllable and high-pressure-resistant alkali metal gain generating device includes a gain cell main body, a laser window, and a heating device. A main gas channel is provided in the gain cell main body. Four laser windows are circumferentially provided on the side wall of the gain cell main body, and a plurality of air curtain grooves are respectively located above each laser window. The air curtain grooves are used to blow inert protective gas onto the inner surface of the laser window. The heating device is arranged in the side wall of the gain cell main body and is disposed around the main gas channel.

[0007] The air curtain grooves are arranged at an acute angle with the main gas channel, and the inner side ports of the air curtain grooves close to the laser window are located above the inner surface of the laser window.

[0008] The outer side ports of each air curtain groove are respectively connected to an air curtain arm.

[0009] A pressure sensing device is provided at the end of the air curtain arm.

[0010] Four mounting ports are circumferentially provided on the side wall of the gain cell body, and the four laser windows are respectively installed in the four mounting ports of the gain cell body, and the inner surfaces of the laser windows are coplanar with the inner wall of the main gas channel; the outer ends of the laser windows are limited by a sealing flange, and the sealing flange is connected to the gain cell body.

[0011] A limiting stop is provided at the outer end of each mounting port on the gain cell body;

[0012] A boss for positioning with the limiting stop in the mounting port is provided at the outer end of the laser window;

[0013] A heat-conducting sealing ring is provided between the inner surface of the boss and the limiting stop in the mounting port, and a heat-conducting washer is provided between the outer surface of the boss and the sealing flange.

[0014] The material of the laser window is sapphire.

[0015] The heating device includes a plurality of electric heating rods, and the plurality of electric heating rods are respectively arranged close to the air curtain groove and the laser window.

[0016] Both ends of the main gas channel are respectively connected to an inlet flange and an outlet flange; ceramic heating sheets are provided on the outer side of one end of the gain cell body close to the outlet flange and on the outlet flange.

[0017] A heat-insulating washer is provided on the outer side of the outlet flange.

[0018] The advantages and beneficial effects of the present invention are:

[0019] The present invention provides a temperature-controllable and high-pressure-resistant alkali metal gain generating device. Through the optimized design of the structure of the gain cell body and the laser window, it not only provides the pressure and temperature conditions for the gain region to ensure the stable operation of the alkali metal laser, but also greatly ensures the fluid uniformity, thereby ensuring the output laser beam quality. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of a temperature-controllable and high-pressure-resistant alkali metal gain generating device of the present invention;

[0021] Figure 2 is Figure 1 the A-A cross-sectional view of

[0022] In the figure: 1 is the inlet flange, 2 is the mainstream gas channel, 3 is the air curtain arm, 4 is the gain cell body, 5 is the electric heating rod, 6 is the air curtain groove, 7 is the laser window, 8 is the sealing flange, 9 is the heat-conducting washer, 10 is the heat-conducting sealing ring, 11 is the ceramic heating sheet, 12 is the outlet flange, and 13 is the heat-insulating washer. Detailed implementation mode

[0023] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] As Figure 1-2 shown, a controllable temperature and high-pressure resistant alkali metal gain generating device provided by the present invention includes a gain cell body 4, a laser window 7, and a heating device. A mainstream gas channel 2 is provided in the gain cell body 4, and the mainstream gas channel 2 is used for the mainstream gas containing alkali metal vapor to pass through; both ends of the mainstream gas channel 2 are respectively connected to the inlet flange 1 and the outlet flange 12, and the inlet flange 1 and the outlet flange 12 are hermetically connected to the upper and lower ends of the gain cell body 4 through bolts to ensure the passage of the mainstream gas. Four laser windows 7 are circumferentially provided on the side wall of the gain cell body 4, and a plurality of air curtain grooves 6 are respectively located above each laser window 7. The air curtain grooves 6 are used to blow inert protective gas onto the inner surface of the laser window 7; the heating device is arranged in the side wall of the gain cell body 4 and is arranged around the mainstream gas channel 2.

[0025] As Figure 1 shown, in the embodiment of the present invention, the air curtain groove 6 is arranged at an acute angle with the mainstream gas channel 2, and the inner side port of the air curtain groove 6 close to the laser window 7 is located above the inner surface of the laser window 7, so that the inert protective gas in the air curtain groove 6 can fully protect the laser window 7 and prevent the laser window 7 from being contaminated by alkali metal vapor.

[0026] Furthermore, the outer side ports of the air curtain grooves 6 are respectively connected to an air curtain arm 3 through a connecting flange. In this embodiment, the air curtain groove 6 forms a 45° angle with the mainstream gas channel 2, and the axis of the air curtain groove 6 is collinear with the axis of the air curtain arm 3. A pressure sensing device is provided at the end of the air curtain arm 3.

[0027] As Figure 2 shown, in the embodiment of the present invention, four installation ports are circumferentially provided on the side wall of the gain cell body 4, and the four laser windows 7 are respectively installed in the four installation ports of the gain cell body 4, and the inner surfaces of the laser windows 7 are coplanar with the inner wall of the mainstream gas channel 2; the outer ends of the laser windows 7 are limited by a sealing flange 8, and the sealing flange 8 is hermetically connected to the gain cell body 4 through bolts. The inner surfaces of the four laser windows 7 are aligned with the inner surface of the gain cell body 4 to avoid the generation of turbulence and vortices when the mainstream gas sweeps at high speed and ensure the uniformity of the high-speed fluid.

[0028] Specifically, a limiting stop is provided at the outer end of each mounting opening on the gain cell body 4. A boss for positioning with the limiting stop in the mounting opening is provided at the outer end of the laser window 7. A heat-conducting sealing ring 10 is provided between the inner surface of the boss and the limiting stop in the mounting opening, and a heat-conducting washer 9 is provided between the outer surface of the boss and the sealing flange 8.

[0029] As Figure 1-2 shown, in the embodiment of the present invention, the heating device includes a plurality of electric heating rods 5, and the plurality of electric heating rods 5 are respectively arranged close to the air curtain groove 6 and the laser window 7.

[0030] In the embodiment of the present invention, ceramic heating sheets 11 are provided on the outer side of one end of the gain cell body 4 close to the outlet flange 12 and on the outlet flange 12. Further, a heat-insulating washer 13 is provided on the outer side of the outlet flange 12. Specifically, the material of the heat-insulating washer 13 is glass fiber, which can effectively block the heat transfer to the outside.

[0031] In the embodiment of the present invention, the laser window 7 adopts a sapphire boss structure, and the inner surface is aligned with the inner side surface of the gain cell body 4, so as to avoid the generation of turbulent vortices. The inner side of the boss of the laser window 7 and the gain cell body 4 are sealed by a heat-conducting sealing ring 10, and the material of the heat-conducting sealing ring 10 is ceramic-filled silicone rubber. The outer side of the boss and the sealing flange 8 are sealed by a heat-conducting washer 9, and the heat-conducting washer 9 is an oxygen-free copper gasket. On the premise of ensuring high-pressure resistance, the heat of the gain cell body 4 is quickly and evenly introduced into the laser window 7.

[0032] In this embodiment, four air curtain grooves 6 with a width of 2 mm are opened around the inside of the gain cell body 4 and are at an angle of 45° with the main gas flow direction. The inner end of the air curtain groove 6 is aligned with the inner surface of the laser window 7. An inert protective gas flows in the air curtain groove 6 to protect the inner surface of the laser window 7 from being polluted by the mainstream gas containing alkali metal vapor. Ten Φ6 power 25w and 60w electric heating rods 5 are arranged longitudinally in the gain cell body 4. Four electric heating rods 5 are arranged longitudinally, and the four longitudinally arranged electric heating rods 5 are in the same direction as the main gas flow direction, and the four electric heating rods 5 are arranged close to the left and right side edges of the laser window 7, as Figure 2 shown. Six electric heating rods 5 are arranged horizontally, and the six horizontally arranged electric heating rods 5 are perpendicular to the main gas flow direction. Two of the electric heating rods 5 are arranged close to the air curtain groove 6, and the other four electric heating rods 5 are horizontally placed at the upper and lower edges of the laser window 7. Six 5-20w ceramic heating sheets 11 are evenly distributed on the upper surface of the outlet flange 12 and the outlet end face of the gain cell body 4, and temperature sensor devices are evenly distributed inside and outside the gain cell body 4 to effectively control the temperature change of the laser window 7.

[0033] In the embodiments of the present invention, multiple electric heating rods 5 and ceramic heating sheets 11 are reasonably arranged in the gain cell body 4, and temperature and pressure sensors are arranged at key positions to ensure heat transfer and temperature control between the window mirror and the gain cell body 4 on the premise of sealing. To balance the requirements of high pressure and lightweight of the gain cell, topological optimization with a compressive strength of 10 MPa is carried out on the overall structure. The finally obtained structure can make the alkali metal vapor in the gain cell be in an appropriate pressure, temperature, and flow field uniformity, providing a favorable environmental guarantee for the efficient and stable operation of the flow-type alkali metal laser.

[0034] The above are only the embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, expansions, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A temperature - controllable and high - pressure - resistant alkali metal gain generating device, characterized in that, it includes a gain cell body (4), a laser window (7) and a heating device. A main gas channel (2) is arranged in the gain cell body (4). Four laser windows (7) are circumferentially arranged on the side wall of the gain cell body (4), and a plurality of air curtain grooves (6) are respectively located above each laser window (7). The air curtain grooves (6) are used to blow inert protective gas onto the inner surface of the laser window (7); the heating device is arranged inside the side wall of the gain cell body (4) and is arranged around the main gas channel (2); Four mounting openings are circumferentially arranged on the side wall of the gain cell body (4). The four laser windows (7) are respectively installed in the four mounting openings of the gain cell body (4), and the inner surfaces of the laser windows (7) are coplanar with the inner wall of the main gas channel (2); the outer ends of the laser windows (7) are limited by a sealing flange (8), and the sealing flange (8) is connected to the gain cell body (4); The inner surfaces of the four laser windows (7) are aligned with the inner surface of the gain cell body (4); The heating device includes a plurality of electric heating rods (5), and the plurality of electric heating rods (5) are respectively arranged close to the air curtain grooves (6) and the laser windows (7); Temperature sensor devices are evenly distributed inside and outside the gain cell body (4) to effectively control the temperature change of the laser window (7).

2. The temperature - controllable and high - pressure - resistant alkali metal gain generating device according to claim 1, characterized in that, The air curtain grooves (6) are arranged at an acute angle with the main gas channel (2), and the inner side port of the air curtain groove (6) close to the laser window (7) is located above the inner surface of the laser window (7).

3. The temperature - controllable and high - pressure - resistant alkali metal gain generating device according to claim 2, characterized in that, The outer side ports of the air curtain grooves (6) are respectively connected to an air curtain arm (3).

4. The temperature - controllable and high - pressure - resistant alkali metal gain generating device according to claim 3, characterized in that, A pressure sensing device is arranged at the end of the air curtain arm (3).

5. The temperature - controllable and high - pressure - resistant alkali metal gain generating device according to claim 1, characterized in that, Limit stop ports are arranged at the outer side ends of the mounting openings on the gain cell body (4); A boss for positioning with the limit stop port in the mounting opening is arranged at the outer side end of the laser window (7); A heat - conducting sealing ring (10) is arranged between the inner surface of the boss and the limit stop port in the mounting opening, and a heat - conducting washer (9) is arranged between the outer surface of the boss and the sealing flange (8).

6. The temperature - controllable and high - pressure - resistant alkali metal gain generating device according to claim 1, characterized in that, The material of the laser window (7) is sapphire.

7. The temperature - controllable and high - pressure - resistant alkali metal gain generating device according to claim 1, characterized in that, Both ends of the main gas channel (2) are respectively connected to an inlet flange (1) and an outlet flange (12); ceramic heating sheets (11) are arranged on the outer side of one end of the gain cell body (4) close to the outlet flange (12) and on the outlet flange (12).

8. The temperature-controllable and high-pressure-resistant alkali metal gain generating device according to claim 7, characterized in that, a heat-insulating washer (13) is provided on the outer side of the outlet flange (12).

Images