Single-layer and double-layer multi-pass pumping optical system

Abstract

The invention provides a single-layer and double-layer multi-pass pumping optical system, which is used for solving the technical problems that the single absorption amount of pumping light by an internal gain medium is relatively high, and a laser head with relatively low requirement on the pumping laser pass number cannot well adapt to the existing pumping optical system. According to the single-layer multi-pass pumping optical system provided by the invention, through the design of the position relation among the plurality of reflectors, the laser head and the parabolic reflector, the pumping laser goes back and forth to the laser head for multiple times; meanwhile, according to the double-layer multi-pass pumping optical system provided by the invention, a large number of reflectors are divided into first reflectors and second reflectors, the first reflectors and the second reflectors are arranged into an inner circle and an outer circle, and meanwhile, the laser head and the parabolic reflector are matched to enable pumping laser to go back and forth to the laser head for multiple times; effective absorption of pumping laser by the laser head is achieved through the gain medium in the laser head, multi-pass energy storage is provided for the laser head more efficiently, and the light path is simple in design and easy to operate.

Description

Technical Field

[0001] The invention relates to a laser head, in particular to a single-layer and double-layer multi-pass pumping optical system. Background Art

[0002] Ultrafast lasers with high average power have important application value in ultra-precision processing, biomedicine and scientific research. At present, only thin-disk laser technology can support high average power and high pulse energy output at the same time. The mainstream heat sink thin-disk laser head has very small single absorption of pump light due to the extremely small thickness of the thin-disk gain medium, so it is necessary to design a very complex pump optical system to improve the pump efficiency.

[0003] Chinese patent CN2023106337037 discloses a transmission / reflection laser head, whose internal gain medium has a high single absorption amount of pump light and a low requirement for the pump laser path number, but this laser head cannot adapt well to the existing pump optical system. Summary of the invention

[0004] The purpose of the present invention is to provide a single-layer and double-layer multi-pass pump optical system to solve the technical problem that the laser head with a high single absorption of pump light by the internal gain medium and a low requirement for the number of pump laser passes cannot adapt well to the existing pump optical system.

[0005] In order to achieve the above purpose, the technical solution provided by the present invention is as follows:

[0006] A single-layer multi-pass pumping optical system, which is special in that it includes 2n reflectors, laser heads coaxially arranged in sequence, a reflector mounting frame and a parabolic reflector, n≥2;

[0007] The reflector mounting frame is axially provided with a light hole, a light inlet and a light outlet; the light hole is located at the center of the reflector mounting frame;

[0008] 2n reflectors are arranged on an end surface of a reflector mounting frame close to the parabolic reflector, and the reflective surface of the reflector is arranged tilted relative to the reflector mounting frame; the 2n reflectors are evenly divided into two groups, and the n reflectors of the first group, the n reflectors of the second group, the light outlet, and the light inlet are evenly distributed along the same circle in sequence;

[0009] The reflection surfaces of the i-th reflection mirror in the first group and the i-th reflection mirror in the second group have the same inclination angle, and the reflection surfaces of the two are arranged opposite to each other, i=1, 2, ..., n;

[0010] The reflective surface of the laser head is located at the focal position of the parabolic reflector;

[0011] The light inlet is located on the incident light path of the pump laser. The incident light of the pump laser is incident on the parabolic reflector through the light inlet, and then goes back and forth n times through the parabolic reflector, the laser head, the parabolic reflector, the i-th reflector of the second group, the i-th reflector of the first group, and the parabolic reflector, and then is reflected by the laser head and the parabolic reflector, and then is emitted through the light outlet; wherein the value of i starts from 1 and increases by 1 every time it goes back and forth;

[0012] The sum of the transmission distances of the pump laser from the parabolic reflector to the i-th reflector in the second group, from the i-th reflector in the second group to the i-th reflector in the first group, and from the i-th reflector in the first group to the parabolic reflector is equal to twice the focal length of the parabolic reflector.

[0013] Furthermore, a zero-degree reflector is provided on the light outlet, which is used to make the pump laser return along the original transmission path after being reflected by the zero-degree reflector, so that the number of paths absorbed by the laser head for the pump laser is increased by 1 times;

[0014] The transmission distance of the pump laser from the parabolic reflector to the zero-degree reflector is equal to the focal length of the parabolic reflector.

[0015] Furthermore, the laser head is a transmissive laser head or a reflective laser head.

[0016] Furthermore, the inclination angles of the reflection surfaces of the 2n reflection mirrors are all 45°.

[0017] Furthermore, said n=4.

[0018] Meanwhile, the present invention also provides another double-layer multi-pass pumping optical system, which is special in that it comprises 2p first reflectors, 2q second reflectors, a laser head coaxially arranged in sequence, a reflector mounting frame and a parabolic reflector, p≥2, q≥2, p≥q;

[0019] The reflector mounting frame is axially provided with a light hole, a light inlet and a light outlet; the light hole is located at the center of the reflector mounting frame;

[0020] The 2p first reflectors and the 2q second reflectors are all arranged on an end surface of a reflector mounting frame close to the parabolic reflector, and the reflecting surfaces of the first reflectors and the second reflectors are both inclined relative to the reflector mounting frame; the lowest point of the reflecting surface of the first reflector is higher than the highest point of the reflecting surface of the second reflector;

[0021] The 2p first reflectors and the 2q second reflectors are respectively divided into two groups, and the p first reflectors of the first group, the p first reflectors of the second group, the light inlet, and the one second reflector of the first group are uniformly arranged along the same circumference in sequence to form a first ring position; the q-1 second reflectors of the first group, the q second reflectors of the second group, and the light outlet are uniformly arranged along the same circumference in sequence in the opposite direction to form a second ring position; the second ring position is located in the inner circle of the first ring position, and the light inlet and the light outlet are located at the same radial position of the first ring position and the second ring position;

[0022] The reflection surfaces of the j-th first reflector in the first group and the j-th first reflector in the second group have the same inclination angle, and the two reflection surfaces are arranged opposite to each other, j=1, 2, ..., p; the reflection surfaces of the k-th second reflector in the first group and the k-th second reflector in the second group have the same inclination angle, and the two reflection surfaces are arranged opposite to each other, k=1, 2, ..., q;

[0023] The reflective surface of the laser head is located at the focal position of the parabolic reflector;

[0024] The light inlet is located on the incident light path of the pump laser. The incident light of the pump laser is incident on the parabolic reflector through the light inlet. The pump laser passes through the parabolic reflector, the laser head, the parabolic reflector, the j-th first reflector of the second group, the j-th first reflector of the first group, and the parabolic reflector for p round trips in sequence, and then is reflected by the parabolic reflector, the laser head, the parabolic reflector, the k-th second reflector of the first group, the k-th second reflector of the second group, and the parabolic reflector for q round trips, and then is reflected by the laser head and the parabolic reflector before being emitted through the light outlet; wherein the value of j starts from 1 and increases by 1 for each round trip; the value of k starts from 1 and increases by 1 for each round trip;

[0025] The sum of the transmission distances of the pump laser from the parabolic reflector to the jth first reflector of the second group, from the jth first reflector of the second group to the jth first reflector of the first group, and from the jth first reflector of the first group to the parabolic reflector is equal to twice the focal length of the parabolic reflector;

[0026] The sum of transmission distances of the pump laser from the parabolic reflector to the kth second reflector of the second group, from the kth second reflector of the second group to the kth second reflector of the first group, and from the kth second reflector of the first group to the parabolic reflector is equal to twice the focal length of the parabolic reflector.

[0027] Furthermore, a zero-degree reflector is provided on the light outlet, which is used to make the pump laser return along the original transmission path after being reflected by the zero-degree reflector, so that the number of paths absorbed by the laser head for the pump laser is increased by 1 times;

[0028] The transmission distance of the pump laser from the parabolic reflector to the zero-degree reflector is equal to the focal length of the parabolic reflector.

[0029] Furthermore, the laser head is a transmissive laser head or a reflective laser head.

[0030] Furthermore, the inclination angles of the reflection surfaces of the 2p first reflection mirrors are all 45°;

[0031] The inclination angles of the reflection surfaces of the 2q second reflection mirrors are all 45°.

[0032] Furthermore, p=6, q=4.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. A single-layer multi-pass pumping optical system provided by the present invention can make the pumping laser go back and forth to the laser head multiple times through multiple reflectors, a laser head and a parabolic reflector. The laser head can effectively absorb the pumping laser through the gain medium inside the laser head, providing multi-pass energy storage for the laser head more efficiently. The optical path design is simple and easy to operate.

[0035] 2. A double-layer multi-pass pumping optical system provided by the present invention divides a large number of reflectors into a first reflector and a second reflector, and arranges them into two inner and outer circles. At the same time, in conjunction with a laser head and a parabolic reflector, the pumping laser can be made to travel back and forth to the laser head for multiple times, and the laser head can effectively absorb the pumping laser for more times through the gain medium inside the laser head.

[0036] 3. The single-layer and double-layer multi-pass pumping optical system of the present invention is provided with a zero-degree reflector at the light outlet. The transmission distance of the pumping laser from the parabolic reflector to the zero-degree reflector is equal to the focal length of the parabolic reflector, which is used to make the pumping laser return along the original transmission path after being reflected by the zero-degree reflector, so that the number of passes of the laser head to absorb the pumping laser is increased by 1 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The structure diagram of a single-layer multi-pass pumping optical system embodiment 1 of the present invention is shown in FIG. Figure 1 ;

[0038] Figure 2 for Figure 1 A longitudinal cross-sectional view of

[0039] Figure 3 It is a schematic diagram of the distribution of eight reflectors, light outlets and light inlets on a reflector mounting frame in the first embodiment of the present invention;

[0040] Figure 4 The structure diagram of the third embodiment of a double-layer multi-pass pumping optical system of the present invention is shown in FIG. Figure 1 ;

[0041] Figure 5 for Figure 4 Longitudinal section view of .

[0042] The specific reference numerals are as follows:

[0043] 1- reflector mounting frame, 11- light hole, 12- light inlet, 13- light outlet; 2- laser head; 3- parabolic reflector. DETAILED DESCRIPTION

[0044] In order to make the advantages and features of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] Embodiment 1

[0046] like Figure 1 , Figure 2 As shown, a single-layer multi-pass pumping optical system includes eight reflectors, a laser head 2 coaxially arranged in sequence, a reflector mounting frame 1, and a parabolic reflector 3. The reflector mounting frame 1 is axially provided with a light hole 11, a light inlet 12, and a light outlet 13, and the light hole 11 is located at the center of the reflector mounting frame 1.

[0047] Eight reflectors are arranged on an end surface of the reflector mounting frame 1 close to the parabolic reflector 3, and the reflective surface of the reflector is inclined relative to the reflector mounting frame 1. The eight reflectors are divided into two groups. The four reflectors in the first group are respectively marked as reflector A1, reflector A2, reflector A3 and reflector A4, and the four reflectors in the second group are respectively marked as reflector B1, reflector B2, reflector B3 and reflector B4. Figure 3 As shown, the reflector A1, the reflector A2, the reflector A3, the reflector A4, the reflector B1, the reflector B2, the reflector B3, the reflector B4, the light outlet 13, and the light entrance 12 are uniformly distributed counterclockwise along the same circumference, that is, the reflector A1 and the reflector B2, the reflector A2 and the reflector B3, the reflector A3 and the reflector B4, the reflector A4 and the light outlet 13, and the reflector B1 and the light entrance 12 are symmetrical about the center point of the reflector mounting frame 1. In other embodiments of the present invention, the eight reflectors, the light outlet 13, and the light entrance 12 may also be uniformly distributed clockwise along the same circumference.

[0048] The reflective surfaces of the reflectors A1 and B1, A2 and B2, A3 and B3, and A4 and B4 are arranged opposite to each other, and the reflective surfaces of the two oppositely arranged reflectors have the same inclination angle. Preferably, in this embodiment, the reflective surface inclination angles of the eight reflectors are all 45°.

[0049] The reflection surface of the laser head 2 is located at the focal position of the parabolic reflector 3. The laser head 2 can be a transmission laser head or a reflection laser head. The light inlet 12 is located on the incident light path of the pump laser, and the reflection surface of the parabolic reflector 3 is located on the incident light path of the pump laser, and is also located on the reflection light path of the reflection surfaces of the laser head 2, the reflector A1, the reflector A2, the reflector A3 and the reflector A4.

[0050] The reflecting surface of reflector A1 is located on the reflecting light path of reflector B1, the reflecting surface of reflector A2 is located on the reflecting light path of reflector B2, the reflecting surface of reflector A3 is located on the reflecting light path of reflector B3, and the reflecting surface of reflector A4 is located on the reflecting light path of reflector B4. The reflecting surface of the reflector B1 is located on the optical path after the pump laser is incident through the light inlet 12 and is reflected by the parabolic reflector 3, the laser head 2 and the parabolic reflector 3 in sequence; the reflecting surface of the reflector B2 is located on the optical path after the pump laser is reflected by the reflector A1, the parabolic reflector 3, the laser head 2 and the parabolic reflector 3 in sequence; the reflecting surface of the reflector B3 is located on the optical path after the pump laser is reflected by the reflector A2, the parabolic reflector 3, the laser head 2 and the parabolic reflector 3 in sequence; the reflecting surface of the reflector B4 is located on the optical path after the pump laser is reflected by the reflector A3, the parabolic reflector 3, the laser head 2 and the parabolic reflector 3 in sequence; and the light outlet 13 is located on the optical path after the pump laser is reflected by the reflector A4, the parabolic reflector 3, the laser head 2 and the parabolic reflector 3 in sequence.

[0051] In order to ensure that the pump laser presents an ideal laser spot effect at the laser head 2, the sum of the transmission distances of the pump laser from the parabolic reflector 3 to the reflector B1, the reflector B1 to the reflector A1, and the reflector A1 to the parabolic reflector 3, the sum of the transmission distances of the pump laser from the parabolic reflector 3 to the reflector B2, the reflector B2 to the reflector A2, and the reflector A2 to the parabolic reflector 3, the sum of the transmission distances of the pump laser from the parabolic reflector 3 to the reflector B3, the reflector B3 to the reflector A3, and the reflector A3 to the parabolic reflector 3, and the sum of the transmission distances of the pump laser from the parabolic reflector 3 to the reflector B4, the reflector B4 to the reflector A4, and the reflector A4 to the parabolic reflector 3 are all equal to twice the focal length of the parabolic reflector 3.

[0052] The working principle of the single-layer multi-pass pumping optical system of the pump laser is as follows:

[0053] The shaped and homogenized pump laser is incident on the reflective surface of the parabolic reflector 3 through the light inlet 12, and then incident on the reflective surface of the laser head 2 through the light hole 11 of the reflector mounting frame 1 after being reflected by the parabolic reflector 3, and then reflected by the laser head 2 to the reflective surface of the parabolic reflector 3, and then reflected by the parabolic reflector 3 to the reflective surface of the reflector B1, and then reflected by the reflector B1 to the reflective surface of the reflector A1, completing the first absorption of the pump laser by the laser head 2; the reflector A1 receives the pump laser The pump laser is reflected to the reflecting surface of parabolic reflector 3, and then reflected to the reflecting surface of laser head 2 by parabolic reflector 3, and then reflected to the reflecting surface of parabolic reflector 3 by laser head 2, and then reflected to the reflecting surface of reflector B2 by parabolic reflector 3, and then reflected to the reflecting surface of reflector A2 by reflector B2, thus completing the second absorption of pump laser by laser head 2; reflector A2 reflects the received pump laser to the reflecting surface of parabolic reflector 3, and then reflects to the laser head by parabolic reflector 3. 2, then reflected by laser head 2 to the reflecting surface of parabolic reflector 3, then reflected by parabolic reflector 3 to the reflecting surface of reflector B3, then reflected by reflector B3 to the reflecting surface of reflector A3, completing the third-pass absorption of pump laser by laser head 2; reflector A3 reflects the received pump laser to the reflecting surface of parabolic reflector 3, then reflected by parabolic reflector 3 to the reflecting surface of laser head 2, then reflected by laser head 2 to the reflecting surface of parabolic reflector 3, then reflected by parabolic reflector The plane reflector 3 reflects to the reflective surface of the reflector B4, and then reflects to the reflective surface of the reflector A4 through the reflector B4, thus completing the fourth-pass absorption of the pump laser by the laser head 2; the reflector A4 reflects the received pump laser to the reflective surface of the parabolic reflector 3, and then reflects to the reflective surface of the laser head 2 through the parabolic reflector 3, and then reflects to the reflective surface of the parabolic reflector 3 through the laser head 2, and then reflects to the light outlet 13 through the parabolic reflector 3, thus completing the fifth-pass absorption of the pump laser by the laser head 2. Through the single-layer multi-pass pump optical system of the present invention, the laser head 2 can effectively absorb the pump laser and provide energy storage for it more efficiently.

[0054] In this embodiment, the light inlet 12 and the light outlet 13 can be used interchangeably, and the transmission path of the pump laser is reversed. The number of reflectors can be increased or decreased by multiples of 2, and accordingly, the absorption path of the laser head 2 for the pump laser will be increased or decreased.

[0055] Embodiment 2

[0056] The structure of the second embodiment is the same as that of the first embodiment, and the only difference is that a zero-degree reflector is provided on the light outlet 13 of the second embodiment, and the transmission distance of the pump laser from the parabolic reflector 3 to the zero-degree reflector is equal to the focal length of the parabolic reflector 3, which is used to make the pump laser return along the original transmission path after being reflected by the zero-degree reflector, so that the number of absorption paths of the pump laser by the laser head 2 is increased by 1 times.

[0057] Embodiment 3

[0058] like Figure 4 , Figure 5 As shown, a double-layer multi-pass pumping optical system includes twelve first reflectors, eight second reflectors, a laser head 2 coaxially arranged in sequence, a reflector mounting frame 1, and a parabolic reflector 3. The reflector mounting frame 1 is axially provided with a light hole 11, a light inlet 12, and a light outlet 13, and the light hole 11 is located at the center of the reflector mounting frame 1.

[0059] The twelve first reflectors and the eight second reflectors are all arranged on an end surface of the reflector mounting frame 1 close to the parabolic reflector 3 , and the reflecting surfaces of the first reflectors and the second reflectors are both inclined relative to the reflector mounting frame 1 .

[0060] The twelve first reflectors are divided into two groups, the six first reflectors in the first group are respectively recorded as first reflector C1, first reflector C2, first reflector C3, first reflector C4, first reflector C5, and first reflector C6, and the six first reflectors in the second group are respectively recorded as first reflector D1, first reflector D2, first reflector D3, first reflector D4, first reflector D5, and first reflector D6; the eight second reflectors are also divided into two groups, the four second reflectors in the first group are respectively recorded as second reflector E1, second reflector E2, second reflector E3, and second reflector E4, and the four second reflectors in the second group are respectively recorded as second reflector F1, second reflector F2, second reflector F3, and second reflector F4. The first reflector C1, the first reflector C2, the first reflector C3, the first reflector C4, the first reflector C5, the first reflector C6, the first reflector D1, the first reflector D2, the first reflector D3, the first reflector D4, the first reflector D5, the first reflector D6, the light entrance port 12 and the second reflector F1 are uniformly distributed along the same circle in a counterclockwise manner, and the first reflector C1 and the first reflector D2, the first reflector C2 and the first reflector D3, the first reflector C3 and the first reflector D4, the first reflector C4 and the first reflector D5, the first reflector C5 and the first reflector D6, the first reflector C6 and the light entrance port 12, the first reflector D1 and the second reflector F1 are respectively symmetrical about the center point of the reflector mounting frame 1. The second reflector E1, the second reflector E2, the second reflector E3, the second reflector E4, the second reflector F2, the second reflector F3, the second reflector F4 and the light outlet 13 are evenly distributed along the same circle in a clockwise manner, so the second reflector E1 and the second reflector F2, the second reflector E2 and the second reflector F3, the second reflector E3 and the second reflector F4, and the second reflector E4 and the light outlet 13 are symmetrical about the center point of the reflector mounting frame 1.

[0061] The thirteen reflectors and the light inlet 12 arranged counterclockwise are recorded as the first ring position, and the seven reflectors and the light outlet 13 arranged clockwise are recorded as the second ring position, and the second ring position is located in the inner circle of the first ring position. In order to avoid interference of the optical path, the lowest point of the reflection surface of the first reflector is higher than the highest point of the reflection surface of the second reflector; at the same time, the light inlet 12 and the light outlet 13 need to be located at the same radial position of the first ring position and the second ring position, and the arrangement order on the first ring position and the second ring position needs to be opposite, so that the reflected light of the second reflector F1 is smoothly transmitted to the second reflector E1 through the top of the light outlet 13, avoiding interference and shielding of the reflected light of the second reflector F1 by other reflectors. In other embodiments of the present invention, the thirteen reflectors and the light inlet 12 on the first ring position can also be evenly distributed along the same circumference in a clockwise manner, and the seven reflectors and the light outlet 13 on the second ring position need to be evenly distributed along the same circumference in a clockwise manner.

[0062] The reflecting surfaces of the first reflector C1 and the first reflector D1, the first reflector C2 and the first reflector D2, the first reflector C3 and the first reflector D3, the first reflector C4 and the first reflector D4, the first reflector C5 and the first reflector D5, the first reflector C6 and the first reflector D6, the second reflector E1 and the second reflector F1, the second reflector E2 and the second reflector F2, the second reflector E3 and the second reflector F3, and the second reflector E4 and the second reflector F4 are arranged opposite to each other, and the reflecting surfaces of the two reflecting mirrors arranged opposite to each other have the same inclination angle. Preferably, in this embodiment, the reflecting surface inclination angles of the twenty reflectors are all 45°.

[0063] The laser head 2 and the parabolic reflector 3 are respectively located on both sides of the reflector mounting frame 1, and the reflective surface of the laser head 2 is located at the focal position of the parabolic reflector 3. The laser head 2 can be a transmission laser head or a reflective laser head. The light inlet 12 is located on the incident light path of the pump laser, and the reflective surface of the parabolic reflector 3 is located on the incident light path of the pump laser, and is also located on the reflective light path of the laser head 2, the first reflector C1, the first reflector C2, the first reflector C3, the first reflector C4, the first reflector C5, the first reflector C6, the second reflector E1, the second reflector E2, the second reflector E3, and the reflective surface of the second reflector E4.

[0064] The reflection surface of the first reflector D1 is located on the reflection light path of the first reflector C1, the reflection surface of the first reflector D2 is located on the reflection light path of the first reflector C2, the reflection surface of the first reflector D3 is located on the reflection light path of the first reflector C3, the reflection surface of the first reflector D4 is located on the reflection light path of the first reflector C4, the reflection surface of the first reflector D5 is located on the reflection light path of the first reflector C5, and the reflection surface of the first reflector D6 is located on the reflection light path of the first reflector C6; the reflection surface of the first reflector C6 is located on the reflection light path of the pump laser after it is incident through the light inlet 12 and is reflected by the parabolic reflector 3, the laser head 2, and the parabolic reflector 3 in sequence, the reflection surface of the first reflector C5 is located on the reflection light path of the pump laser after it is incident through the first reflector D6, the parabolic reflector 3, on the reflected light path after the laser head 2 and the parabolic reflector 3 are reflected, the reflecting surface of the first reflector C4 is located on the reflected light path after the pump laser is reflected by the first reflector D5, the parabolic reflector 3, the laser head 2 and the parabolic reflector 3 in sequence, the reflecting surface of the first reflector C3 is located on the reflected light path after the pump laser is reflected by the first reflector D4, the parabolic reflector 3, the laser head 2 and the parabolic reflector 3 in sequence, the reflecting surface of the first reflector C2 is located on the reflected light path after the pump laser is reflected by the first reflector D3, the parabolic reflector 3, the laser head 2 and the parabolic reflector 3 in sequence, and the reflecting surface of the first reflector C1 is located on the reflected light path after the pump laser is reflected by the first reflector D2, the parabolic reflector 3, the laser head 2 and the parabolic reflector 3 in sequence.

[0065] The reflecting surface of the second reflector E1 is located on the reflecting light path of the second reflector F1, the reflecting surface of the second reflector E2 is located on the reflecting light path of the second reflector F2, the reflecting surface of the second reflector E3 is located on the reflecting light path of the second reflector F3, and the reflecting surface of the second reflector E4 is located on the reflecting light path of the second reflector F4; the reflecting surface of the second reflector F1 is located on the reflecting light path of the pump laser after it is reflected by the first reflector D1, the parabolic reflector 3, the laser head 2, and the parabolic reflector 3 in sequence, and the reflecting surface of the second reflector F2 is located on the reflecting light path of the pump laser after it is reflected by the second reflector E1, the parabolic reflector 3, the laser head 2, and the parabolic reflector 3 in sequence. The reflecting surface of the second reflector F3 is located on the reflected light path after the pump laser is reflected by the second reflector E2, the parabolic reflector 3, the laser head 2, and the parabolic reflector 3 in sequence. The reflecting surface of the second reflector F4 is located on the reflected light path after the pump laser is reflected by the second reflector E3, the parabolic reflector 3, the laser head 2, and the parabolic reflector 3 in sequence. The light outlet 13 is located on the reflected light path after the pump laser is reflected by the second reflector E1, the parabolic reflector 3, the laser head 2, and the parabolic reflector 3 in sequence.

[0066] In order to ensure that the pump laser presents an ideal laser spot effect at the laser head 2, the sum of the transmission distances of the pump laser from the parabolic reflector 3 to the first reflector D1, the first reflector D1 to the first reflector C1, and the first reflector C1 to the parabolic reflector 3; the sum of the transmission distances of the pump laser from the parabolic reflector 3 to the first reflector D2, the first reflector D2 to the first reflector C2, and the first reflector C2 to the parabolic reflector 3; the sum of the transmission distances of the pump laser from the parabolic reflector 3 to the first reflector D3, the first reflector D3 to the first reflector C3, and the first reflector C3 to the parabolic reflector 3; the sum of the transmission distances of the pump laser from the parabolic reflector 3 to the first reflector D4, the first reflector D4 to the first reflector C4, and the first reflector C4 to the parabolic reflector 3; the first reflector D5, the first reflector D5 to the first reflector The sum of the transmission distances from the first reflector C5, the first reflector C5 to the parabolic reflector 3, the sum of the transmission distances from the first reflector D6, the first reflector D6 to the first reflector C6, the first reflector C6 to the parabolic reflector 3, the second reflector F1, the second reflector F1 to the second reflector E1, the sum of the transmission distances from the second reflector E1 to the parabolic reflector 3, the second reflector F2, the second reflector F2 to the second reflector E2, the sum of the transmission distances from the second reflector E2 to the parabolic reflector 3, the second reflector F3, the second reflector F3 to the second reflector E3, the sum of the transmission distances from the second reflector E3 to the parabolic reflector 3, the second reflector F4, the second reflector F4 to the second reflector E4, the second reflector E4 to the parabolic reflector 3 are all equal to twice the focal length of the parabolic reflector 3.

[0067] The working principle of the double-layer multi-pass pumping optical system of the pump laser is as follows:

[0068] After the shaped and homogenized pump laser is incident through the light inlet 12, it is reflected by the parabolic reflector 3, the laser head 2, the parabolic reflector 3, and the first reflector D1 in sequence and arrives at the first reflector C1, completing the first-pass absorption of the pump laser by the laser head 2; after the first reflector C1 reflects the received pump laser, it is reflected by the parabolic reflector 3, the laser head 2, the parabolic reflector 3, and the first reflector D2 in sequence and arrives at the first reflector C2, completing the second-pass absorption of the pump laser by the laser head 2; after the first reflector C2 reflects the received pump laser, it is reflected by the parabolic reflector 3, the laser head 2, the parabolic reflector 3, and the first reflector D3 in sequence and arrives at the first Reflector C3 completes the third-pass absorption of the pump laser by the laser head 2; the first reflector C3 reflects the received pump laser, which is reflected by parabolic reflector 3, laser head 2, parabolic reflector 3, and first reflector D4 in sequence before arriving at the first reflector C4, completing the fourth-pass absorption of the pump laser by the laser head 2; the first reflector C4 reflects the received pump laser, which is reflected by parabolic reflector 3, laser head 2, parabolic reflector 3, and first reflector D5 in sequence before arriving at the first reflector C5, completing the fifth-pass absorption of the pump laser by the laser head 2; the first reflector C5 reflects the received pump laser, which is reflected by parabolic reflector 3, laser head 2, After being reflected by the parabolic reflector 3 and the first reflector D6, the laser beam reaches the first reflector C6, completing the sixth absorption of the pump laser by the laser head 2; after the first reflector C6 reflects the received pump laser, it is reflected by the parabolic reflector 3, the laser head 2, the parabolic reflector 3, and the second reflector F1 in sequence and reaches the second reflector E1, completing the seventh absorption of the pump laser by the laser head 2; after the second reflector E1 reflects the received pump laser, it is reflected by the parabolic reflector 3, the laser head 2, the parabolic reflector 3, and the second reflector F2 in sequence and reaches the second reflector E2, completing the eighth absorption of the pump laser by the laser head 2; After the pump laser is reflected, it is reflected by the parabolic reflector 3, the laser head 2, the parabolic reflector 3, and the second reflector F3 in sequence before reaching the second reflector E3, completing the ninth pass absorption of the pump laser by the laser head 2; after the second reflector E3 reflects the received pump laser, it is reflected by the parabolic reflector 3, the laser head 2, the parabolic reflector 3, and the second reflector F4 in sequence before reaching the second reflector E4, completing the tenth pass absorption of the pump laser by the laser head 2; after the second reflector E4 reflects the received pump laser, it is reflected by the parabolic reflector 3, the laser head 2, and the parabolic reflector 3 in sequence before reaching the light outlet 13, completing the eleventh pass absorption of the pump laser by the laser head 2. Through the double-layer multi-pass pump optical system of the present invention, the laser head 2 can effectively absorb more passes of the pump laser and provide energy storage for it more efficiently.

[0069] In this embodiment, the light inlet 12 and the light outlet 13 can also be used interchangeably, and the transmission path of the pump laser is reversed. The number of reflectors can be increased or decreased by multiples of 2, and accordingly, the absorption path of the laser head 2 for the pump laser will be increased or decreased.

[0070] Embodiment 4

[0071] The structure of the fourth embodiment is the same as that of the third embodiment, and the only difference is that a zero-degree reflector is provided on the light outlet 13 of the second embodiment, and the transmission distance of the pump laser from the parabolic reflector 3 to the zero-degree reflector is equal to the focal length of the parabolic reflector 3, which is used to make the pump laser return along the original transmission path after being reflected by the zero-degree reflector, so that the number of absorption paths of the pump laser by the laser head 2 is increased by 1 times.

[0072] The above description is only used to illustrate the technical solution of the present invention rather than to limit it. For ordinary professional and technical personnel in the field, the specific technical solution recorded in the above embodiment can be modified, or some of the technical features therein can be replaced by equivalents, and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution protected by the present invention.

Claims

1. A single-layer multi-pass pumping optical system, characterized in that: It comprises 2n reflecting mirrors, a laser head (2) coaxially arranged in sequence, a reflecting mirror mounting frame (1) and a parabolic reflecting mirror (3), where n≥2; The reflector mounting frame (1) is axially provided with a light through hole (11), a light inlet (12) and a light outlet (13); the light through hole (11) is located at the center of the reflector mounting frame (1); 2n reflectors are arranged on an end surface of a reflector mounting frame (1) close to a parabolic reflector (3), and the reflective surfaces of the reflectors are arranged at an angle relative to the reflector mounting frame (1); the 2n reflectors are evenly divided into two groups, and the n reflectors in the first group, the n reflectors in the second group, the light outlet (13), and the light inlet (12) are evenly distributed along the same circumference in sequence; The reflection surfaces of the i-th reflection mirror in the first group and the i-th reflection mirror in the second group have the same inclination angle, and the reflection surfaces of the two are arranged opposite to each other, i=1, 2, ..., n; The reflection surface of the laser head (2) is located at the focal position of the parabolic reflector (3); The light inlet (12) is located on the incident light path of the pump laser. The incident light of the pump laser is incident on the parabolic reflector (3) through the light inlet (12), and then goes back and forth through the parabolic reflector (3), the laser head (2), the parabolic reflector (3), the i-th reflector of the second group, the i-th reflector of the first group, and the parabolic reflector (3) for n round trips, and then is reflected by the laser head (2) and the parabolic reflector (3), and then is emitted through the light outlet (13); wherein the value of i starts from 1 and increases by 1 after each round trip. The sum of the transmission distances of the pump laser from the parabolic reflector (3) to the i-th reflector in the second group, from the i-th reflector in the second group to the i-th reflector in the first group, and from the i-th reflector in the first group to the parabolic reflector (3) is equal to twice the focal length of the parabolic reflector (3).

2. The single-layer multi-pass pumping optical system according to claim 1, characterized in that: The light outlet (13) is provided with a zero-degree reflector for allowing the pump laser to return along the original transmission path after being reflected by the zero-degree reflector; The transmission distance of the pump laser from the parabolic reflector (3) to the zero-degree reflector is equal to the focal length of the parabolic reflector (3).

3. The single-layer multi-pass pumping optical system according to claim 1 or 2, characterized in that: The laser head (2) is a transmission laser head or a reflection laser head.

4. The single-layer multi-pass pumping optical system according to claim 3, characterized in that: The inclination angles of the reflection surfaces of the 2n reflection mirrors are all 45°.

5. The single-layer multi-pass pumping optical system according to claim 4, characterized in that: Said n=4.

6. A double-layer multi-pass pumping optical system, characterized in that: It comprises 2p first reflecting mirrors, 2q second reflecting mirrors, a laser head (2) coaxially arranged in sequence, a reflecting mirror mounting frame (1) and a parabolic reflecting mirror (3), p≥2, q≥2, p≥q; The reflector mounting frame (1) is axially provided with a light through hole (11), a light inlet (12) and a light outlet (13); the light through hole (11) is located at the center of the reflector mounting frame (1); The 2p first reflectors and the 2q second reflectors are all arranged on an end surface of a reflector mounting frame (1) close to a parabolic reflector (3), and the reflection surfaces of the first reflectors and the second reflectors are both arranged tilted relative to the reflector mounting frame (1); the lowest point of the reflection surface of the first reflector is higher than the highest point of the reflection surface of the second reflector; The 2p first reflectors and the 2q second reflectors are respectively divided into two groups, wherein the p first reflectors in the first group, the p first reflectors in the second group, a light inlet (12), and a second reflector in the first group are uniformly arranged in sequence along the same circumference to form a first ring position; the q-1 second reflectors in the first group, the q second reflectors in the second group, and a light outlet (13) are uniformly arranged in sequence along the same circumference in the opposite direction to form a second ring position; the second ring position is located in the inner circle of the first ring position, and the light inlet (12) and the light outlet (13) are located at the same radial position of the first ring position and the second ring position; The reflection surfaces of the j-th first reflector in the first group and the j-th first reflector in the second group have the same inclination angle, and the two reflection surfaces are arranged opposite to each other, j=1, 2, ..., p; the reflection surfaces of the k-th second reflector in the first group and the k-th second reflector in the second group have the same inclination angle, and the two reflection surfaces are arranged opposite to each other, k=1, 2, ..., q; The reflection surface of the laser head (2) is located at the focal position of the parabolic reflector (3); The light inlet (12) is located on the incident light path of the pump laser. The incident light of the pump laser is incident on the parabolic reflector (3) through the light inlet (12). The pump laser passes through the parabolic reflector (3), the laser head (2), the parabolic reflector (3), the jth first reflector of the second group, the jth first reflector of the first group, and the parabolic reflector (3) for p round trips in sequence. Then, the pump laser passes through the parabolic reflector (3), the laser head (2), the parabolic reflector (3), the kth second reflector of the first group, the kth second reflector of the second group, and the parabolic reflector (3) for q round trips. Then, the pump laser passes through the laser head (2) and the parabolic reflector (3) and is then emitted through the light outlet (13). The value of j starts from 1 and increases by 1 every time it goes back and forth. The value of k starts from 1 and increases by 1 every time it goes back and forth. The sum of the transmission distances of the pump laser from the parabolic reflector (3) to the jth first reflector of the second group, the jth first reflector of the second group to the jth first reflector of the first group, and the jth first reflector of the first group to the parabolic reflector (3) is equal to twice the focal length of the parabolic reflector (3); The sum of the transmission distances of the pump laser from the parabolic reflector (3) to the kth second reflector in the second group, the kth second reflector in the second group to the kth second reflector in the first group, and the kth second reflector in the first group to the parabolic reflector (3) is equal to twice the focal length of the parabolic reflector (3).

7. The double-layer multi-pass pumping optical system according to claim 6, characterized in that: The light outlet (13) is provided with a zero-degree reflector for allowing the pump laser to return along the original transmission path after being reflected by the zero-degree reflector; The transmission distance of the pump laser from the parabolic reflector (3) to the zero-degree reflector is equal to the focal length of the parabolic reflector (3).

8. The double-layer multi-pass pumping optical system according to claim 6 or 7, characterized in that: The laser head (2) is a transmission laser head or a reflection laser head.

9. The double-layer multi-pass pumping optical system according to claim 8, characterized in that: The reflection surfaces of the 2p first reflection mirrors each have an inclination angle of 45°; The inclination angles of the reflection surfaces of the 2q second reflection mirrors are all 45°.

10. The double-layer multi-pass pumping optical system according to claim 9, characterized in that: Said p=6, q=4.

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