CN115832829A - Multi-pass laser amplifier based on disc crystal - Google Patents

Abstract

The invention discloses a multi-pass laser amplifier based on a disc crystal, which comprises: a disc crystal and a multipass channel reflection panel; the multi-pass channel reflection panel is provided with a plurality of reflectors, two reflectors are combined and surrounded from inside to outside to form a multi-layer reflection ring, each layer of reflection ring is provided with an incident port for seed light incidence and an emergent port for amplified light emergence, and the emergent port of the inner layer reflection ring in the two adjacent layers of reflection rings is the incident port of the outer layer reflection ring. The invention utilizes the disc gain medium, ensures the high beam quality of the laser, and enables the incident seed light to realize multiple reflection through the disc crystal through the designed multi-pass amplification channel, thereby greatly improving the light-light conversion efficiency from the pump light to the seed laser, realizing higher ultrafast laser power and light pulse energy and achieving higher laser gain.

Description

Multi-pass laser amplifier based on disc crystal

Technical Field

The invention relates to the technical field of laser, in particular to a multi-pass laser amplifier based on a disc crystal.

Background

The solid laser has the advantages of high power, high pulse energy, stability, proper price and the like, and is widely applied to the fields of military affairs, industrial processing, medical treatment and scientific research. However, for the conventional solid-state laser, the gain medium crystal is mostly rod-shaped, and when the gain medium crystal is pumped at high power, the radial parabolic temperature distribution of the crystal generates a thermal lens, so that the beam quality and the laser stability are greatly influenced, which is also a main reason for limiting the development of the high-power and high-energy solid-state laser.

The disc laser achieves the purpose of efficient heat dissipation by using the geometric shape of the gain material, and provides a way for realizing high-power and high-pulse-energy laser. Many commercial high-power ultrafast laser systems are realized by disc regeneration and amplification. The disk regenerative amplifier based on the CPA technology can output ultrafast pulses with high beam quality and single pulse energy higher than 200 mJ, improve the repetition frequency and realize single-mode output close to 2kW and 800 fs. However, there are three obvious technical limitations to further increase the optical power and pulse energy of the current disc-based regenerative amplifier: 1. the regenerative amplifier requires an intra-cavity optical switch, and the size and damage threshold of the pockels electro-optic crystal tend to limit the optical pulse energy output of the disc regenerative amplifier. 2. Regenerative amplifiers lack flexibility in terms of adaptable high repetition rates due to the high voltage pulses required to drive the electro-optic crystal of the pockels cell, which are in the order of nanoseconds. 3. Laser cavity design and electronic, software control systems are relatively complex. The multi-pass amplifier based on the disc gain medium can well overcome the three limitations, and is an important technical means for further improving the power and energy of the ultrafast pulse laser at present.

Disclosure of Invention

The embodiment of the invention provides a multi-pass laser amplifier based on a disc crystal, aiming at improving the light conversion efficiency from pump light to output laser, thereby realizing higher ultrashort laser power and pulse energy.

The embodiment of the invention provides a multi-pass laser amplifier based on a disc crystal, which comprises: a disc crystal and a multipass channel reflection panel; a plurality of reflectors are distributed on the multi-path channel reflection panel, two reflectors are combined and surrounded from inside to outside on the multi-path channel reflection panel to form a multi-layer reflection ring, each layer of reflection ring is provided with an incident port for seed light incidence and an emergent port for seed light emergence, and the emergent port of the inner layer reflection ring in two adjacent layers of reflection rings is the incident port of the outer layer reflection ring; wherein the entrance port and the exit port are interchangeable;

seed light enters the disc crystal, enters the reflectors of the innermost reflecting ring through the entrance ports of the innermost reflecting ring of the multi-path channel reflecting panel, returns to the disc crystal after being reflected by each pair of reflectors, enters the next reflector of the innermost reflecting ring through the disc crystal, and so on until passing through the reflectors of all the reflecting rings and being emitted from the exit ports of the outermost reflecting ring.

Furthermore, the number of the reflectors in the reflector ring is sequentially increased from inside to outside, and from inside to outside, the number of the reflectors in the odd-numbered reflector ring is odd, and the number of the reflectors in the even-numbered reflector ring is even; in each layer of reflecting ring, the reflectors combined in pairs correspond to each other in pairs through reflector assembling hole positions, and the rest reflectors are combined in pairs with the rest reflectors in the adjacent layer of reflecting ring and correspond to each other in pairs through reflector assembling hole positions.

Furthermore, 4-60 reflectors are distributed on the multi-pass channel reflecting panel, the 4-60 reflectors form a multilayer reflecting ring from inside to outside, and the 4-60 reflectors form different channel numbers.

Furthermore, 34 reflectors are distributed on the multi-path channel reflecting panel, and the 34 reflectors respectively form a first reflecting ring, a second reflecting ring and a third reflecting ring from inside to outside.

Further, the first circle comprises 3 mirrors, the second circle comprises 12 mirrors, and the third circle comprises 19 mirrors; the first reflector is provided with 3 reflector mounting and adjusting hole positions, the second reflector is provided with 12 reflector mounting and adjusting hole positions, the third reflector is provided with 19 reflector mounting and adjusting hole positions,

furthermore, the disc crystal and the multi-path channel reflecting panel are arranged in parallel relatively and are connected through a bottom plate; the disc crystal and the multi-pass channel reflecting panel are perpendicular to the bottom plate, and a connecting line between the center of the disc crystal and the center of the multi-pass channel reflecting panel is perpendicular to parallel planes of the disc crystal and the multi-pass channel reflecting panel.

Further, the spacing between the disc crystal and the multi-pass channel reflective panel is at least 500mm.

Further, the radius of curvature of the disc crystal is larger than 50m.

The optical disc device further comprises a film polarizer arranged at the front end of the disc crystal along the optical path direction, and the seed light is incident to the disc crystal after passing through the film polarizer.

Furthermore, the multi-pass reflection panel also comprises a quarter wave plate and a rear reflector combination which are arranged at the rear end of the multi-pass reflection panel along the direction of the light path;

after passing through the quarter-wave plate, the seed light is changed into s polarization from p polarization, returns to the thin film polarizer through the original path of the rear reflector, and is reflected by the thin film polarizer, so that the multiple path number is multiplied.

The embodiment of the invention utilizes the advantages of the disk crystal in improving the thermal effect of the crystal and the characteristic of high absorption efficiency of the crystal on the pumping energy, and the designed multi-pass amplification channel enables the incident seed light to realize multiple reflections through the disk crystal, thereby greatly improving the light-light conversion efficiency from the pumping light to the seed laser and further realizing higher ultrafast laser power and light pulse energy.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a multi-pass laser amplifier based on a disc crystal according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of multi-pass reflection of an optical path in a multi-pass laser amplifier based on a disc crystal according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of mirror coding in a multi-pass laser amplifier based on a disc crystal according to an embodiment of the present invention;

fig. 4 is a simulation diagram of the change of the spot mode of a multi-pass laser amplifier based on a disc crystal in the transmission process according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the specification of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

Referring to fig. 1 and 2, an embodiment of the invention provides a multi-pass laser amplifier based on a disc crystal, including: a disc crystal 1 and a multi-pass channel reflection panel 2; a plurality of reflectors 3 are distributed on the multi-path channel reflection panel 2, two reflectors 3 are combined and surrounded on the multi-path channel reflection panel 2 from inside to outside to form a plurality of reflection rings, each reflection ring is provided with an incident port for seed light incidence and an emergent port for seed light emergence, and the emergent port of the inner reflection ring in two adjacent layers of reflection rings is the incident port of the outer reflection ring; wherein the entrance port and the exit port are interchangeable;

as shown in fig. 2, the seed light enters the disc crystal 1, enters the reflectors 3 of the innermost reflecting ring through the entrance ports of the innermost reflecting ring of the multipass channel reflecting panel 2, is reflected by each pair of reflectors 3, returns to the disc crystal, enters the next reflector 3 of the innermost reflecting ring through the disc crystal 1, and so on until passing through all the reflectors 3 of the innermost reflecting ring and exits through the exit ports of the outermost reflecting ring.

In this embodiment, the multi-pass laser amplifier based on a disc crystal mainly includes: the optical disc comprises a disc crystal 1 and a multi-pass channel reflecting panel 2, wherein the multi-pass channel reflecting panel 2 is provided with a plurality of reflectors 3 which are combined in pairs and distributed on the multi-pass channel reflecting panel in an annular manner to form at least one layer of reflecting ring from inside to outside. The seed light is incident and then hits the center of the disc crystal 1 and hits the multi-pass channel reflecting panel 2, then is reflected by the reflecting mirror 3 in the multi-pass channel reflecting panel 2 and then hits the disc crystal again and coincides with the last hit light spot, and the returning light of the disc crystal 1 falls on the center of the next reflecting mirror 3 until passing through all the reflecting mirrors 3, and is hit out from the exit of the outermost reflecting ring and passes through the multiple disc crystal reflection gain superposition, thereby realizing the amplification of the ultrafast laser.

The embodiment utilizes the advantage that the disc crystal improves the thermal effect of the crystal and the characteristic that the crystal has high absorption efficiency on the pumping energy, and the designed multi-pass amplification channel enables the incident seed light to realize multiple reflections through the disc crystal 1, thereby greatly improving the light conversion efficiency from the pumping light to the seed laser and further realizing higher laser gain. The multi-pass laser amplifier described in this embodiment may be applied to a scenario where the pulse duration (e.g., from ms to fs), the pulse repetition rate (e.g., from kHz to GHz), and the adjustable pulse train shape need to be amplified, that is, the multi-pass laser amplifier has high flexibility and high versatility, and can well perform improvement of optical pulse energy and power for various types of laser systems. In particular, the multi-pass laser amplifier described in this embodiment is particularly suitable for precision machining of high-difficulty materials such as sapphire, display glass, ceramics, and metals in the industrial field, laser weapons in the military field, and micro-nano machining, pumping detection, nonlinear optics and other different scenes in the scientific research field. Also, in this embodiment, compared with the prior art, the disc crystal 1 is used as a laser gain medium in a multi-pass laser amplifier. That is, the conventional bulk solid crystal can realize amplification of hundreds of watts and picoseconds due to the inherent influence of heat dissipation and nonlinear effect, and the disc gain medium adopted in the embodiment can perfectly solve the two problems, and can realize ultrahigh-speed (femtosecond and picosecond) laser amplification of kilowatt or ten-thousand watts. In addition, since the disc crystal has a low non-linear effect and a small thermal lens effect, the present embodiment is particularly suitable for the application scenario of ultra-short pulse amplification. In addition, the present embodiment can be used as a supplementary part based on a disc regeneration amplifier to further improve the optical pulse energy and power of the ultrafast laser.

It should be noted that all the reflectors 3 in this embodiment are mounted on the multi-pass reflective panel 2 without adding any additional auxiliary mirrors, which are usually required in the prior art to be arranged on (or around) a structure similar to the reflective panel and/or a disc crystal. Therefore, compared with the prior art, the method greatly reduces the complexity of the system, thereby realizing a more stable, reliable and simple industrial implementation scheme.

In one embodiment, the number of the reflectors 3 in the reflector ring is sequentially increased from inside to outside, and from inside to outside, the number of the reflectors 3 in the odd-numbered reflector ring is odd, and the number of the reflectors 3 in the even-numbered reflector ring is even; in each layer of reflecting ring, the reflectors 3 combined in pairs correspond to each other in pairs through the reflector mounting and adjusting hole positions, and the remaining reflectors 3 are combined in pairs with the remaining reflectors 3 in the adjacent layer of reflecting ring and correspond to each other in pairs through the reflector mounting and adjusting hole positions. In a specific embodiment, the reflector positioning holes are reflector frames, that is, two reflectors 3 are respectively mounted at two ends of the reflector frame to form a pair of reflector frames, for example, when 5 reflectors 3 are included in the non-outermost reflector ring, except that one reflector 3 needs to correspond to one reflector 3 in the adjacent reflector ring, the remaining 4 reflectors 3 are respectively mounted on two pairs of reflector frames.

In one embodiment, the multipass channel reflecting panel 2 is distributed with 4-60 reflectors 3,4-60 reflectors 3 to form a multi-layer reflecting ring from inside to outside, and the 4-60 reflectors form different number of channels. Of course, in other embodiments, other numbers of mirrors 3 may be used, for example, 80 mirrors, 100 mirrors, etc., and the reflecting ring formed by the mirrors 3 has at least one layer, may have two layers, or may have 5 layers, 6 layers, etc. However, in a limited space, as the number of layers increases, the difficulty of implementing the structure of the disc crystal is increased piece by piece, and of course, theoretically, the more the number of turns is, the larger the number of channels reflected on the disc crystal 1 is, the larger the energy extraction is, and the better the effect is.

In a specific embodiment, 34 reflectors 3 are distributed on the multi-pass reflective panel 2, and the 34 reflectors 3 respectively form a first reflective ring, a second reflective ring and a third reflective ring from inside to outside.

Further, the first circle comprises 3 mirrors 3, the second circle comprises 12 mirrors 3, and the third circle comprises 19 mirrors 3; the first reflector ring is provided with 3 reflector adjustment hole positions, the second reflector ring is provided with 12 reflector adjustment hole positions, and the third reflector ring is provided with 19 reflector adjustment hole positions.

In this embodiment, seed light is incident from the innermost circle (i.e., the first reflection ring) during tuning, the first reflection ring has 3 reflector tuning holes (1 pair of reflection frames + the first reflection ring to 1 pair of reflection frames of the second reflection ring), and the incidence light passing order is respectively marked as C1 to C3; the middle ring is provided with 12 mounting and adjusting hole positions 4 (5 pairs of reflecting frames, an inner ring, a middle ring, 1 pair of reflecting frames, a middle ring and 1 pair of reflecting frames), and the incident light passing is marked as B1-B12 in sequence; 19 reflector mounting and adjusting hole positions (9 pairs of reflecting frames + the middle ring to 1 pair of reflecting frames) are arranged on the outer ring, and the positions are marked as A1-A19 according to the reflection; three turns total 17 pairs of reflector frames. Through reasonable angle design, the seed light is incident and then strikes the center of the disc crystal 1, then passes through each pair of reflecting frames and then strikes the disc crystal 1 again and is superposed with the light spot which is struck in last time, and the return light of the disc crystal 1 falls on the center of the mirror surface of the next reflecting frame. And after the light passes through 17 pairs of reflecting frames, the light spots which are hit on the center of the disc crystal 1 for 18 times can be coincided, and finally the high-power ultrafast laser which is subjected to 18 times of reflection gain superposition of the disc crystal 1 is hit from an exit port. Of course, in other embodiments, other channel numbers may be used to achieve the ultrashort laser amplification, even if the seed light undergoes other numbers of reflections, for example, 4 reflections, that is, the seed light hits the center of the disc crystal 1 for 4 times, or 36 channels are used to make the seed light undergo 36 reflections, and so on.

Referring to fig. 3, 17 pairs of reflector frames are as follows in the light-passing order:

the first reflecting ring 1 comprises: C1-C2;

the first to second reflection circles 1 pair: C3-B1;

the second reflector 5 pair: B2-B3, B4-B5, B6-B7, B8-B9, B10-B11;

the second to third reflection circles 1 pair: B12-A1;

the third reflector 9 pair: A2-A3, A4-A5, A6-A7, A8-A9, A10-A11, A12-A13, A14-A15, A16-A17, A18-A19.

In one embodiment, the disc crystal 1 and the multi-pass reflective panel 2 are disposed in parallel and connected via a bottom plate; the disc crystal 1 and the multi-pass channel reflecting panel 2 are both perpendicular to the bottom plate, and a connecting line between the center of the disc crystal 1 and the center of the multi-pass channel reflecting panel 2 is perpendicular to parallel planes of the disc crystal 1 and the multi-pass channel reflecting panel 2. Further, the radius of curvature of the disc crystal 1 is larger than 50m. Furthermore, the multipass channel reflecting panel 2, the reflector 3, the reflector adjusting hole site and the bottom plate are all treated by water cooling to reduce the heat effect generated by absorbing the pump light, thereby prolonging the service life of the multipass laser amplifier. In a specific application scenario, the disc crystal 1 is placed in a laser box, the laser box is provided with a first hole site for seed light input and output, correspondingly, the multi-pass channel reflection panel is provided with a second hole site for seed light input and output, and the first hole site is horizontally aligned with the second hole site. Preferably, a lifting mechanism is arranged below the laser box body and used for adjusting the height of the laser box body so as to enable the first hole position of the laser box body to be horizontally aligned with the second hole position on the multi-pass channel reflection panel 2.

In one embodiment, the spacing between the disc crystal 1 and the multi-pass reflective panel 2 is at least 500mm. The 500mm mentioned in this embodiment is the minimum achievable pitch of the multi-pass laser amplifier, and certainly, other pitches (greater than 500 mm) can also be achieved, but in this embodiment, in order to achieve miniaturization of the multi-pass laser amplifier, the minimum value is taken here, that is, 500mm.

In one embodiment, the optical disc drive further comprises a thin film polarizer disposed at the front end of the disc crystal 1 along the optical path direction, and the seed light is incident on the disc crystal 1 after passing through the thin film polarizer.

Furthermore, the multi-path reflecting panel also comprises a quarter wave plate and a rear reflector combination which are arranged at the rear end of the multi-path reflecting panel 2 along the direction of the light path;

after passing through the quarter-wave plate, the seed light is changed into s polarization from p polarization, returns to the thin film polarizer through the original path of the rear reflector, and is reflected by the thin film polarizer, so that the multiple path number is multiplied.

In the embodiment, the Thin Film Polarizer (TFP) is added at the input end of the multi-pass laser amplifier, and the combination of the quarter-wave plate and the rear reflector is added at the tail end of the emergent light path of the multi-pass laser amplifier, so that the original return of the light path is more easily realized, and the effect of multiplying the number of multi-pass light paths is achieved. For example, the multi-pass laser amplifier can achieve 18 channels before adding the thin film polarizer and the quarter wave plate, back mirror, and 2 x 18 channels, i.e., 36 channels, after adding the thin film polarizer and the quarter wave plate, back mirror.

According to the multi-pass laser amplifier based on the disc crystal provided by the embodiment of the invention, through reasonable optical path design, for the disc crystal with curvature (for example, the curvature radius is more than 50 m), the size of a light spot which is shot on the disc crystal 1 every time can be at a peak point and is basically consistent through reasonable incident light collimation simulation (as shown in fig. 4), so that the light spot divergence caused by overlong optical path can be avoided, and the stability of the system is improved due to the consistency of light beams which are shot into the disc crystal every time. In fig. 4, the optical path simulation diagram is a light beam of 1030nm infrared light with M2=1.1 and a spot radius of 1.4mm, which is incident into the multi-pass laser amplifier based on the disc crystal according to the embodiment of the present invention, and the infrared light passes through the disc crystal 1 and 34 mirrors 3 on the multi-pass channel reflection panel 2 for 18 times in total to finally exit out a spot path diagram, where the total optical path of 18 passes is close to 21m, and the total optical path of 36 passes is close to 42M.

The optical path design advantage of the multi-pass laser amplifier based on the disc crystal provided by the embodiment of the invention is as follows:

1. the modulation amplitude of the beam diameter is small, namely the minimum diameter in the multi-pass laser amplifier is larger than 2.8mm, so that the damage of an optical lens and the ionization of air caused by too small light spots are avoided, and the high-power and high-energy laser pulse output can be realized;

2. the multi-pass laser amplifier only adopts the disc crystal 1 with a certain curvature, and other optical devices are plane mirrors, so that light dispersion occurring in the transmission process of light is compensated. Preferably, the peak power can be further enhanced by using flakes with a larger radius of curvature.

3. The beam diameter varies between 3.2 and 2.8mm along the propagation direction. The radius of the light beam passing through the disc crystal 1 is constant each time, so that high overlapping degree of the light beam can be realized, matching of amplified light and pumping light spots is facilitated, and higher-efficiency amplification and light beam stability are realized.

The embodiments are described in a progressive manner in the specification, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description. It should be noted that, for those skilled in the art, it is possible to make several improvements and modifications to the present application without departing from the principle of the present application, and such improvements and modifications also fall within the scope of the claims of the present application.

It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.

Claims (10)

1. A multi-pass laser amplifier based on a disc crystal, comprising: a disc crystal and a multipass channel reflection panel; a plurality of reflectors are distributed on the multi-path channel reflection panel, two reflectors are combined and surrounded from inside to outside on the multi-path channel reflection panel to form a multi-layer reflection ring, each layer of reflection ring is provided with an incident port for seed light incidence and an emergent port for seed light emergence, and the emergent port of the inner layer reflection ring in two adjacent layers of reflection rings is the incident port of the outer layer reflection ring; wherein the entrance port and the exit port are interchangeable;

the seed light enters the disc crystal, enters the reflectors of the innermost reflecting ring through the entrance ports of the innermost reflecting ring of the multi-path channel reflecting panel, returns to the disc crystal after being reflected by each pair of reflectors, enters the next reflector of the innermost reflecting ring through the disc crystal, and so on until passing through the reflectors of all the reflecting rings and being emitted from the exit ports of the outermost reflecting ring.

2. A multi-pass laser amplifier based on a disc crystal as claimed in claim 1, wherein the number of the mirrors in the reflection rings is increased from inside to outside in sequence, and from inside to outside, the number of the mirrors in the odd-numbered reflection rings is odd, and the number of the mirrors in the even-numbered reflection rings is even; in each layer of reflecting ring, the reflectors combined in pairs correspond to each other in pairs through reflector mounting and adjusting hole positions, and the rest reflectors are combined in pairs with the rest reflectors in the adjacent layer of reflecting ring and correspond to each other in pairs through reflector mounting and adjusting hole positions.

3. A multi-pass laser amplifier based on disc crystal as claimed in claim 2, wherein 4-60 reflectors are distributed on the multi-pass channel reflection panel, 4-60 reflectors form a multi-layer reflection ring from inside to outside, and 4-60 reflectors form different number of channels.

4. A multi-pass laser amplifier according to claim 3, wherein 34 mirrors are distributed on said multi-pass channel reflection panel, and said 34 mirrors form a first reflection ring, a second reflection ring and a third reflection ring from inside to outside.

5. A multiple pass disc crystal based laser amplifier according to claim 4, wherein the first turn comprises 3 mirrors, the second turn comprises 12 mirrors, and the third turn comprises 19 mirrors; the first reflector is provided with 3 reflector adjustment hole positions, the second reflector is provided with 12 reflector adjustment hole positions, and the third reflector is provided with 19 reflector adjustment hole positions.

6. A disc crystal-based multipass laser amplifier according to claim 1, wherein said disc crystal and said multipass channel reflecting panel are disposed in parallel and connected by a bottom plate; the disc crystal and the multi-pass channel reflecting panel are perpendicular to the bottom plate, and a connecting line between the center of the disc crystal and the center of the multi-pass channel reflecting panel is perpendicular to parallel planes of the disc crystal and the multi-pass channel reflecting panel.

7. A disc crystal-based multipass laser amplifier according to claim 6, wherein the spacing between the disc crystal and the multipass channel reflecting panel is at least 500mm.

8. The multi-pass disc crystal-based laser amplifier of claim 1, wherein the radius of curvature of the disc crystal is greater than 50m.

9. The multi-pass laser amplifier based on a disc crystal as claimed in claim 1, further comprising a thin film polarizer disposed at a front end of the disc crystal along an optical path direction, wherein the seed light is incident to the disc crystal after passing through the thin film polarizer.

10. A multi-pass disc crystal-based laser amplifier according to claim 9, further comprising a quarter-wave plate and a back mirror combination disposed at the back end of the multi-pass channel reflection panel along the optical path direction;

after passing through the quarter-wave plate, the seed light is changed into s polarization from p polarization, returns to the thin film polarizer through the original path of the rear reflector, and is reflected by the thin film polarizer, so that the multiple path number is multiplied.

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