A chip amplifier pump cavity structure

Abstract

The present invention belongs to the field of high-power solid-state lasers, and in particular, relates to a novel high-efficiency and compact sheet-shaped amplifier pump cavity structure. The sheet-shaped amplifier pump cavity structure comprises a light box I, a light box II, a sheet frame, an upper triangular plate reflector, a lower triangular plate reflector and a structural support, and is characterized in that: the back of the closely spaced xenon lamps in the light boxes I and II adopts a short-wing imitation involute silver-plated reflector; the upper and lower triangular plate reflectors are arranged in a V shape. A high-efficiency and compact sheet-shaped laser amplifier pump cavity structure with a more compact structure, a larger small signal gain coefficient and better gain uniformity is provided.

Description

Technical Field

[0001] The invention belongs to the field of high-power solid-state lasers, and in particular relates to a novel high-efficiency and compact sheet-shaped amplifier pump cavity structure. Background Art

[0002] In the 30-year development history of high-power solid-state laser drivers, laser driver technology has developed rapidly. In particular, inspired by laser inertial confinement fusion technology, important units and laboratories in many countries around the world have conducted extensive research on ultra-high-power laser drivers of various scales and levels. Among these laser drivers, a very important module is the sheet laser amplifier, which mainly solves the problem of longitudinal energy flow transfer and conversion of the device. It is the core part of the entire driver. The quality of its performance directly affects the output energy and power of the device, and has an important impact on the overall performance of the system. In a sheet laser amplifier, the role of the pump cavity is to efficiently and uniformly transmit the pump light emitted by the pump source to the surface of the gain medium. Parameters such as pump density, cavity transmission efficiency, pump uniformity and pump cavity volume are the main parameters for measuring the level of a pump cavity.

[0003] At present, the pump cavity structure of the commonly used sheet laser amplifiers at home and abroad is xenon lamp array pumping, with a flat plate or involute reflector on the back. The design cannot take into account the volume, pump density and pump efficiency. Taking a 400mm diameter amplifier as an example, the most commonly used arrangement of xenon lamps in the pump cavity is 6-8-6. Further increasing the number of lamps will lead to increased plasma absorption, while reducing cavity transmission efficiency and device reliability. This is a bottleneck for amplifiers that pursue higher gain and higher integration.

[0004] Therefore, there is an urgent need for an optimized device for the pump density, efficiency, size and uniformity of the pump cavity of a slab laser amplifier. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a high-efficiency and compact sheet laser amplifier pump cavity structure with compact structure, large small signal gain coefficient and good gain uniformity based on structural design and parameter optimization.

[0006] The basic idea of ​​the present invention is to rationally design the pump cavity structure based on the traditional sheet laser amplifier pump cavity: based on the number of closely packed xenon lamps, the involute reflector on the back of the xenon lamp is supplemented with a suitable correction coefficient; the position and angle of the upper and lower triangular plate reflectors are optimized; the relative positions of the components in the pump cavity are further compactly designed, so as to achieve the goal of improving the cavity transmission efficiency and reducing the volume of the pump cavity. The specific technical solution is that the sheet laser amplifier pump cavity structure includes a light box I, a light box II, a sheet cavity, an upper triangular plate reflector, a lower triangular plate reflector and a structural support. The light box consists of a closely packed xenon lamp array, a short-wing involute reflector, partition glass and structural support parts. A short-wing imitation involute silver-plated reflector is used on the back of the xenon lamp to provide a planar pump source with high efficiency and spatially uniform irradiation. The cavity is a metal frame placed at the Brewster angle, which is used to install and fix the gain medium. The upper and lower triangular plate reflectors are arranged in a "V" shape to reflect part of the xenon lamp light onto the gain medium and improve the cavity transmission efficiency. The structural support parts provide structural support and shape retention for all components.

[0007] The involute correction coefficient of the short-wing simulated involute silver-plated reflector is 1.2-1.5, and the wingspan correction coefficient is 240-280.

[0008] The upper triangular plate reflector and the lower triangular plate reflector are arranged in a V shape, with a short side angle of 6° and a long side angle of 3°.

[0009] There are 14 lamps in the light box.

[0010] The upper triangular plate reflector and the lower triangular plate reflector are respectively located on the upper and lower surfaces of the film box, and are respectively composed of two pieces, the larger piece forms an angle of 3° with the top or bottom plane of the film cavity, and the smaller piece forms an angle of 6° with the top or bottom plane of the film cavity, the bottom end of the upper triangular plate reflector is flush with the lower edge of the pressing frame that fixes the gain medium, and the top end of the lower triangular plate reflector is flush with the upper edge of the pressing frame; the light box I and the light box II are asymmetrically displaced relative to the film box along the main light path direction, and the right side surface of the light box I and the left side surface of the light box II are respectively parallel to the left edge line and the right edge line of the gain medium; in the light boxes I and II, flat plate reflectors are provided on the sides.

[0011] Beneficial effects: Each light box in the present invention is composed of 14 thin lamps, which reduces the diameter of the xenon lamp and increases the number of xenon lamps compared to the existing pump cavity level, thereby improving the light efficiency and uniformity. By optimizing the short-wing imitation involute reflector on the back of the xenon lamp, the reduction in efficiency is avoided. This design ensures that the pump density and pump uniformity of the pump cavity are improved without reducing the efficiency, or the efficiency and pump uniformity are improved at the same pump density;

[0012] The invention adjusts the angles of the triangle plate reflectors at the end and bottom of the cavity, thereby improving the transmission efficiency of the xenon lamp in the pump cavity;

[0013] The present invention further optimizes the position and size of each component in the cavity, thereby greatly reducing the size of the pump cavity while ensuring the performance, and reducing the length by about 20 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the pump cavity structure of the sheet laser amplifier of the present invention.

[0015] Figure 2 It is a schematic diagram of the positional relationship between the upper and lower triangular plate reflectors and the gain medium.

[0016] Figure 3 It is a schematic diagram of the short wing involute reflector.

[0017] Explanation of the reference numerals: 1.1 - light box I; 1.2, light box II; 2 - sheet frame; 3.1 - upper triangular plate reflector; 3.2 - lower triangular plate reflector; 4 - short wing involute reflector; 5 - xenon lamp; 6 - structural support; 7 - partition glass; 8 - gain medium. DETAILED DESCRIPTION

[0018] The principle design and specific implementation of a highly efficient and compact sheet-shaped laser amplifier pump cavity disclosed in the present invention are described below in conjunction with the embodiments and drawings, but this should not limit the protection scope of the present invention.

[0019] This embodiment takes a sheet-shaped neodymium glass laser amplifier pump cavity with a light aperture of 400mm×400mm as an example to illustrate the specific implementation of the high-efficiency and compact sheet-shaped laser amplifier pump cavity proposed by the present invention.

[0020] Figure 1 The schematic diagram of the structure of the plate-shaped laser amplifier pump cavity in one embodiment of the present invention includes a lamp box I1.1, a lamp box II1.2, a sheet frame 2, a lower triangular plate reflector 3.2, an upper triangular plate reflector 3.1, a structural support 6, and cooling components and electrical supply components are not shown in the figure. The structural support frame 6 is the outer frame of the amplifier; the lamp box I1.1 and the lamp box II1.2 are both composed of a xenon lamp 5, a short wing involute reflector 4 and a partition glass 7.

[0021] In the embodiment, the number of xenon lamps 5 is given according to the amplifier pump density requirement, and the curve parameter equation of the short-wing simulated involute reflector 4 on the back of the xenon lamp 5 is given by the following formula.

[0022] X=-R(cos(α / 2)+(α / 2)sin(α / 2))

[0023] Y=R(sin(α / 2)-(α / 2)cos(α / 2))k

[0024] In the equation, R is the base circle radius of the involute, which adjusts the distance from the lamp to the reflector, k is the pseudo-involute correction coefficient, which adjusts the wingspan, and α is the expansion angle of the involute, in radians.

[0025] The radius of the xenon lamp is 1.55, R = 0.61, k = 1.5, α = 1 to 280, and the following set is obtained Figure 3 Schematic diagram of the positional relationship between the upper triangular plate reflector 3.1, the lower triangular plate reflector 3.2 and the gain medium 8.

[0026] The involute correction coefficient of the short wing involute reflector 4 is 1.2 to 1.5, and the span correction coefficient is 240 to 280. The upper triangular plate reflector 3.1 and the lower triangular plate reflector 3.2 are arranged in a V shape, with a short side angle of 6° and a long side angle of 3°.

[0027] Based on the above technical solution, the number of lamps in the light box is preferably 14. The upper triangular reflector 3.1 and the lower triangular reflector 3.2 are located on the upper and lower surfaces of the film box, respectively, and are composed of two pieces, the larger piece is at an angle of 5° to the top or bottom plane of the film cavity, and the smaller piece is at an angle of 10° to the top or bottom plane of the film cavity. Figure 2 A and B are free edges of two reflectors respectively, and point C is the intersection of the two boundary edges. With this point as the boundary, the length ratio of the other free edges of the two reflectors is 2 to 1. The bottom end of the upper triangular reflector 3.1 is flush with the lower edge of the pressing frame that fixes the gain medium 8, and the top end of the lower triangular plate reflector 3.2 is flush with the upper edge of the pressing frame; the light box I and light box II are asymmetrically displaced relative to the sheet box along the main light path, and the right side surface of the light box I and the left side surface of the light box II are parallel to the left edge line and the right edge line of the gain medium 8 respectively; in the light boxes I and II, flat reflectors are provided on the sides. This can effectively reduce the size of the sheet laser amplifier, and at the same time, reducing the distance between the reflector and the gain medium 8 can increase the reflection of the xenon light by the reflector, thereby improving the utilization rate of the xenon light.

[0028] The preparation process of all reflectors is to first plate 10μm copper on the reflecting plane, then plate a layer of silver with a thickness of not less than 40μm, polish the surface to a mirror finish after silver plating, and finally coat a layer of SiO2 protective film on the silver-plated surface.

[0029] The partition glass of the light box is coated with a double-sided anti-reflection broadband chemical film, so that the average transmittance of the xenon light is greater than 94%.

[0030] In the present invention, each light box is composed of 14 thin lamps, which reduces the diameter of the xenon lamp and increases the number of xenon lamps compared to the existing pump cavity level, thereby improving the light efficiency and uniformity. By optimizing the short-wing imitation involute reflector on the back of the xenon lamp, the reduction of efficiency is avoided. This design ensures that the pump density and pump uniformity of the pump cavity are improved without reducing the efficiency, or the efficiency and pump uniformity are improved at the same pump density.

[0031] The invention adjusts the angles of the triangle plate reflectors at the end and bottom of the sheet cavity, thereby improving the transmission efficiency of the xenon lamp in the pump cavity.

[0032] The present invention further optimizes the position and size of each component in the cavity, thereby greatly reducing the size of the pump cavity while ensuring the performance, and reducing the length by about 20 mm.

Claims

1. A sheet amplifier pump cavity structure, comprising a light box I, a light box II, a sheet frame, an upper triangular plate reflector, a lower triangular plate reflector and a structural support, characterized in that: The back of the closely packed xenon lamps in light box I and light box II adopts a short-wing imitation involute silver-plated reflector; the upper and lower triangular plate reflectors are arranged in a V shape; the upper triangular plate reflector and the lower triangular plate reflector are respectively located on the upper and lower surfaces of the film box, and are respectively composed of two pieces, the larger piece forms an angle of 3° with the top or bottom plane of the film cavity, and the smaller piece forms an angle of 6° with the top or bottom plane of the film cavity, the bottom end of the upper triangular reflector is flush with the lower edge of the pressing frame fixing the gain medium, and the top end of the lower triangular plate reflector is flush with the upper edge of the pressing frame; the light box I and light box II are asymmetrically displaced relative to the film box along the main light path, and the right side surface of the light box I and the left side surface of the light box II are respectively parallel to the left edge line and the right edge line of the gain medium; in the light box I and light box II, flat plate reflectors are provided on the sides.

2. The chip amplifier pump cavity structure according to claim 1, characterized in that: The involute correction coefficient of the short-wing simulated involute silver-plated reflector is 1.2 to 1.5, and the wingspan correction coefficient is 240 to 280.

3. The chip amplifier pump cavity structure according to claim 1 or 2, characterized in that: The upper triangular plate reflector and the lower triangular plate reflector are arranged in a V shape, with a short side angle of 6° and a long side angle of 3°.

4. The chip amplifier pump cavity structure according to claim 3, characterized in that: There are 14 lamps in the light box.

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