Disk crystal based laser amplifier

Abstract

The application relates to the field of laser technology and provides a disc crystal-based laser amplifier, which comprises: each pair of right-angle prisms comprises a first right-angle prism and a second right-angle prism, the first right-angle prism and the second right-angle prism are respectively located on the two sides of an optical axis, the light-out surface of the second right-angle prism in the front pair of right-angle prisms is oppositely arranged with the light-in surface of the first right-angle prism in the rear pair of right-angle prisms, so that the light rays pass through the multiple pairs of right-angle prisms in sequence; a first parabolic mirror is oppositely arranged with the multiple pairs of right-angle prisms; a disc crystal amplification module is located at the focal point of the first parabolic mirror; the first parabolic mirror is used for reflecting the light rays passing through the first right-angle prism to the disc crystal amplification module for amplification gain, and reflecting the light rays reflected by the disc crystal amplification module to the second right-angle prism. The disc crystal-based laser amplifier can make the light rays pass through the disc crystal amplification module multiple times for amplification gain, and thus the average power of the light ray output is improved.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and more particularly to a laser amplifier based on a disk crystal. Background Technology

[0002] In fields such as laser processing, high-precision detection, and optoelectronic countermeasures, ultrashort pulse lasers, which simultaneously possess high average power, high pulse energy, high repetition rate, and high beam quality, are attracting increasing attention. As a representative of third-generation solid-state lasers, disk lasers offer advantages such as low thermal distortion in the gain medium and the ability to output high-beam-quality ultrashort pulse lasers, but they struggle to simultaneously guarantee high average power and high single-pulse energy. Amplifying a low-energy, low-power but high-beam-quality ultrashort pulse laser using a disk multi-pass laser amplifier allows the output light to possess both the high quality and short pulse width characteristics of the seed light while simultaneously increasing the output energy and power. Disk multi-pass laser amplifiers can achieve optical amplification from continuous to femtosecond, amplifying high-repetition-rate ultrashort pulses and achieving laser output with average power in the kW range and pulse energy in the mJ range. Furthermore, the disk crystal itself has low thermal distortion, and the beam quality remains almost unaffected by the amplification system throughout the amplification process, exhibiting extremely high stability. Therefore, disk multi-pass laser amplifiers have become an important research direction in laser technology.

[0003] Disk laser amplifiers use disk crystals as the gain medium, fully utilizing the advantages of disk crystals such as high energy extraction efficiency, low thermal distortion, and weak nonlinear effects to amplify pulsed seed light and achieve high-energy laser output. Based on the amplification mechanism, disk laser amplifiers can be mainly divided into regenerative disk laser amplifiers and multi-pass disk laser amplifiers.

[0004] Currently, regenerative disk laser amplifiers can achieve ultrashort pulse laser output with an average power of 600W and a pulse energy of 100mJ. While regenerative disk laser amplifiers can achieve high pulse energy laser output, they are limited by the Pockels electro-optic crystal, making it difficult to achieve an average power output in the kW range, which also limits the achievable repetition rate. Therefore, providing a new type of disk laser amplifier has become a pressing issue in the industry. Summary of the Invention

[0005] This invention provides a laser amplifier based on a disk crystal to address the deficiency of low average power output in existing disk laser amplifiers.

[0006] This invention provides a laser amplifier based on a disk crystal, comprising: multiple pairs of right-angle prisms, each pair including a first right-angle prism and a second right-angle prism, the first and second right-angle prisms being located on opposite sides of the optical axis, the light-emitting surface of the second right-angle prism in the preceding pair being opposite to the light-incident surface of the first right-angle prism in the following pair, so that light passes through the multiple pairs of right-angle prisms sequentially; a first parabolic reflector, opposite to the multiple pairs of right-angle prisms; and a disk crystal amplification module located at the focal point of the first parabolic reflector; wherein the first parabolic reflector is used to reflect the light passing through the first right-angle prism to the disk crystal amplification module for amplification gain, and to reflect the light reflected by the disk crystal amplification module to the second right-angle prism.

[0007] According to the present invention, a laser amplifier based on a disk crystal is provided, the disk crystal amplification module comprising: a disk crystal disposed at the focal point of a first parabolic reflector, wherein the optical axes of the disk crystal, each pair of right-angle prisms, and the first parabolic reflector coincide; a pair of prisms symmetrically disposed on both sides of the disk crystal; and a pair of second parabolic reflectors located between the disk crystal and the right-angle prisms, wherein the optical axes of the pair of second parabolic reflectors coincide with the optical axis of the disk crystal, and the distance between the pair of second parabolic reflectors is less than the distance between the pair of right-angle prisms.

[0008] According to the present invention, a laser amplifier based on a disk crystal further includes: a first reflector, wherein the first reflector is located upstream of the first right-angle prism of the first pair of right-angle prisms along the direction of light propagation.

[0009] According to the present invention, a laser amplifier based on a disk crystal further includes a polarizer, wherein the polarizer is located upstream of the first reflector along the direction of light propagation.

[0010] According to the present invention, a laser amplifier based on a disk crystal is provided, wherein the reflection angle of the first reflector is 45°.

[0011] According to the present invention, a laser amplifier based on a disk crystal is provided, wherein the polarization angle of the polarizer is 56°.

[0012] According to the present invention, a laser amplifier based on a disk crystal further includes: a λ / 4 waveplate, wherein the λ / 4 waveplate is located downstream of a second right-angle prism that is not aligned with the right-angle prism along the direction of light propagation, and the light-emitting surface of the second right-angle prism that is not aligned with the right-angle prism faces the λ / 4 waveplate.

[0013] According to the present invention, a laser amplifier based on a disk crystal further includes a second reflector located downstream of the λ / 4 waveplate along the direction of light propagation.

[0014] According to the present invention, in a laser amplifier based on a disk crystal, the reflection angle of the second reflector is 0°.

[0015] According to the present invention, a laser amplifier based on a disk crystal is provided, wherein the surfaces of the first right-angle prism, the second right-angle prism, the first reflector, the second reflector, and the first parabolic reflector are coated with a reflective film, the density of the reflective film is greater than or equal to 99.5%, and the wavelength of the light transmitted through the reflective film is 1030 nm.

[0016] The laser amplifier based on a disk crystal provided by this invention, by setting multiple pairs of right-angle prisms and a first parabolic reflector, allows light to pass through the disk crystal amplification module multiple times to increase gain, thereby improving the average power of the light output; at the same time, the laser amplifier based on a disk crystal provided by this invention uses fewer optical components, reducing the size and complexity of the laser amplifier. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the laser amplifier based on a disk crystal provided by the present invention;

[0019] Figure label:

[0020] 10: Disc crystal amplification module; 11: Disc crystal; 12: Prism; 13: Second parabolic reflector; 21: First right-angle prism; 22: Second right-angle prism; 30: First parabolic reflector; 40: First reflector; 50: Polarizer; 60: λ / 4 waveplate; 70: Second reflector. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0022] The terms "first" and "second" in the specification and claims of this invention may explicitly or implicitly include one or more of those features. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0023] The following is combined with Figure 1 The present invention describes a disk-based crystal-based laser amplifier.

[0024] like Figure 1 As shown, in an embodiment of the present invention, the laser amplifier based on a disk crystal includes: a disk crystal amplification module 10, multiple pairs of right-angle prisms, and a first parabolic reflector 30. Each pair of right-angle prisms includes a first right-angle prism 21 and a second right-angle prism 22, which are respectively located on opposite sides of the optical axis. The light-emitting surface of the second right-angle prism 22 in the first pair of right-angle prisms is opposite to the light-incident surface of the first right-angle prism 21 in the second pair of right-angle prisms, so that light passes through multiple pairs of right-angle prisms sequentially. The first parabolic reflector 30 is opposite to the multiple pairs of right-angle prisms. The disk crystal amplification module 10 is located at the focal point of the first parabolic reflector 30. The first parabolic reflector 30 is used to reflect the light passing through the first right-angle prism 21 to the disk crystal amplification module 10 for amplification and gain, and to reflect the light reflected by the disk crystal amplification module 10 to the second right-angle prism 22.

[0025] Specifically, the light emitted from the seed light source first enters the first right-angle prism 21 of the first pair of right-angle prisms. After exiting the first right-angle prism 21, it enters the first parabolic reflector 30 and is reflected by the first parabolic reflector 30 to the disc crystal amplification module 10. The seed light is then extracted and amplified by the disc crystal amplification module 10 and reflected back to the first parabolic reflector 30. The first parabolic reflector 30 reflects the light to the second right-angle prism 22 of the first pair of right-angle prisms. The light is then reflected by the second right-angle prism 22 back to the first right-angle prism 21 in the second pair of right-angle prisms. The light then passes through the second right-angle prism... The light beam passes through the first right-angle prism 21 in the prism array again and enters the first parabolic reflector 30. It is reflected by the first parabolic reflector 30 to the disc crystal amplification module 10 for further amplification and gain, and then reflected back to the first parabolic reflector 30. The light is then reflected again by the first parabolic reflector 30 to the second right-angle prism 22 of the second pair of right-angle prisms. The light is then reflected by the second right-angle prism 22 of the second pair of right-angle prisms to the first right-angle prism 21 of the third pair of right-angle prisms. Following this method, the light passes through each pair of right-angle prisms sequentially, allowing the light to undergo multiple amplification and gain processes by the disc crystal amplification module 10. According to experimental results, the initial seed light parameters are a single-pulse energy of 12 mJ, a wavelength of 1030 nm, and a pulse width of 35 ns, with an output light energy of 48 mJ. After 16 amplification and gain processes, the beam quality factor can reach M. 2 =1.00, with an average output light power of 145mJ.

[0026] Furthermore, in this embodiment, the length direction of the first parabolic reflector 30 is the same as the arrangement direction of the multiple pairs of right-angle prisms.

[0027] It is understood that in this embodiment, as long as enough pairs of right-angle prisms are set, multiple extractions and amplifications of light can be achieved, with the number of extraction passes reaching tens or even hundreds, thereby significantly increasing the average power of the light.

[0028] The laser amplifier based on a disk crystal provided in this embodiment of the invention can amplify the light by setting multiple pairs of right-angle prisms and a first parabolic reflector, thereby increasing the average power of the light output. At the same time, the laser amplifier based on a disk crystal provided in this embodiment of the invention uses fewer optical components, reducing the size and complexity of the laser amplifier.

[0029] Furthermore, in an embodiment of the present invention, the surfaces of the first parabolic reflector 30, each first right-angle prism 21 and each second right-angle prism 22 are coated with a reflective film, the density of the reflective film is greater than or equal to 99.5%, and the wavelength of light that can pass through the reflective film is 1030nm.

[0030] like Figure 1As shown, in an embodiment of the present invention, the disc crystal amplification module 10 includes: a disc crystal 11, a pair of prisms 12, and a pair of second parabolic mirrors 13. The disc crystal 11 is disposed at the focal point of the first parabolic mirror 30, and the optical axes of the disc crystal 11, each pair of right-angle prisms, and the first parabolic mirror 30 coincide. The pair of prisms 12 are symmetrically disposed on both sides of the disc crystal 11, and the pair of second parabolic mirrors 13 are located between the disc crystal 11 and the multiple pairs of right-angle prisms. The optical axes of the pair of second parabolic mirrors 13 coincide with the optical axis of the disc crystal 11, and the distance between the pair of second parabolic mirrors 13 is less than the distance between the pair of right-angle prisms.

[0031] Specifically, the disc crystal 11 is made of Yb:YAG, and a pair of prisms 12 are symmetrically arranged on both sides of the disc crystal 11 to provide laser energy storage and amplify the incoming seed light. A pair of second parabolic mirrors 13 are located between the disc crystal 11 and the first parabolic mirror 30. The gap between the pair of second parabolic mirrors 13 forms a light channel, allowing the light reflected by the disc crystal 11 to pass through the light channel and enter the first parabolic mirror 30. In this embodiment, the light reflected by the first parabolic mirror 30 can all reach the same focal point, so the disc crystal 11 is positioned at the focal point of the first parabolic mirror 30.

[0032] Optionally, in this embodiment, the prism 12 is a right-angle prism.

[0033] like Figure 1 As shown, in one embodiment of the present invention, the laser amplifier based on a disk crystal further includes a first reflector 40. The first reflector 40 is located upstream of the first right-angle prism 21 of the first pair of right-angle prisms along the direction of light propagation.

[0034] Specifically, the seed light passes through the first reflecting mirror 40 and enters the first right-angle prism 21 of the first pair of right-angle prisms. Optionally, the reflection angle of the first reflecting mirror 40 is 45°. The surface of the first reflecting mirror 40 is coated with a reflective film with a density greater than or equal to 99.5%, and the wavelength of light that can pass through the reflective film is 1030nm.

[0035] Furthermore, such as Figure 1 As shown, in an embodiment of the present invention, the laser amplifier based on a disk crystal further includes a polarizer 50. The polarizer 50 is located upstream of the first reflecting mirror 40 along the direction of light propagation.

[0036] Specifically, the polarizer 50 is used to adjust the seed light to a horizontal polarization state. In this embodiment, the polarization angle of the polarizer 50 is 56°. After passing through the polarizer 50, the seed light enters the first reflecting mirror 40.

[0037] like Figure 1As shown, in an embodiment of the present invention, the laser amplifier based on a disk crystal further includes a λ / 4 waveplate 60. Along the direction of light propagation, the λ / 4 waveplate 60 is located downstream of the second right-angle prism 22 (which has no right-angle prisms), and the light-emitting surface of the second right-angle prism 22 faces the λ / 4 waveplate 60.

[0038] Specifically, the λ / 4 waveplate 60 is used to adjust the polarization state of the laser to vertical polarization. After multiple amplifications, the light passes through the second right-angle prism 22 (which has no right-angle prisms) and is then incident on the λ / 4 waveplate 60.

[0039] Furthermore, the disk crystal-based laser amplifier also includes a second reflector 70. The second reflector 70 is located downstream of the λ / 4 waveplate 60 along the direction of light propagation.

[0040] Specifically, the reflection angle of the second mirror 70 is 0°. After the light has been amplified multiple times, its polarization state is adjusted to vertical polarization after passing through the λ / 4 wave plate 60. After the light enters the second mirror 70, it is reflected by the second mirror 70 and returns to the polarizer 50 along the original propagation path before being emitted.

[0041] Furthermore, in this embodiment, the surface of the second reflector 70 is coated with a reflective film, the density of which is greater than or equal to 99.5%, and the wavelength of light that can pass through the reflective film is 1030nm.

[0042] The following is Figure 1 The working principle of the laser amplifier based on disk crystal provided by the present invention will be explained in detail using the illustrated embodiment as an example.

[0043] The low-power laser output from the seed light source is adjusted to a horizontal polarization state after passing through polarizer 50. Then, after passing through first reflector 40, it enters the first right-angle prism 21 of the first pair of right-angle prisms. After exiting through the first right-angle prism 21, it enters the first parabolic reflector 30 and is reflected by the first parabolic reflector 30 to the disk crystal amplification module 10. The seed light is extracted and amplified by the disk crystal 11 and then reflected back to the first parabolic reflector 30. The first parabolic reflector 30 reflects the light to the second right-angle prism 22 of the first pair of right-angle prisms, and then reflects it to the second pair of right-angle prisms. The light rays pass through the first right-angle prism 21 in the second pair of right-angle prisms and then enter the first parabolic mirror 30 again. After being amplified and gained by the first parabolic mirror 30, the light rays are reflected back to the disc crystal 11 and then reflected back to the first parabolic mirror 30. The light rays are then reflected again by the first parabolic mirror 30 to the second right-angle prism 22 of the second pair of right-angle prisms. The light rays are then reflected by the second right-angle prism 22 of the second pair of right-angle prisms to the first right-angle prism 21 of the third pair of right-angle prisms. This process is repeated until the light rays exit through the second right-angle prism 22 of the last pair of right-angle prisms.

[0044] After being amplified multiple times, the light beam passes through a λ / 4 waveplate 60, which adjusts its polarization state to vertical polarization. The beam then enters the second reflecting mirror 70 and is reflected back along its original propagation path to the polarizer 50 before exiting. During this return journey, the light beam is amplified multiple times again by the disc crystal 11, significantly increasing its average power.

[0045] The laser amplifier based on a disk crystal provided in this invention, by setting a second reflector, allows light that has undergone multiple amplifications to undergo multiple amplifications again during its return along the original path, achieving a double amplification effect with a single device and significantly improving the performance parameters of the light.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser amplifier based on a disk crystal, characterized in that, include: Multiple pairs of right-angle prisms, each pair of right-angle prisms including a first right-angle prism and a second right-angle prism, the first right-angle prism and the second right-angle prism are respectively located on both sides of the optical axis, the light-emitting surface of the second right-angle prism in the first pair of right-angle prisms is arranged opposite to the light-incident surface of the first right-angle prism in the second pair of right-angle prisms, so that light passes through the multiple pairs of right-angle prisms in sequence; The first parabolic reflector is arranged opposite to the plurality of right-angle prisms; The disc crystal amplification module is located at the focal point of the first parabolic reflector; The first parabolic reflector is used to reflect light passing through the first right-angle prism to the disc crystal amplification module for amplification and gain, and to reflect light reflected from the disc crystal amplification module to the second right-angle prism. The disc crystal amplification module includes: a disc crystal disposed at the focal point of the first parabolic reflector, wherein the optical axes of the disc crystal, each pair of right-angle prisms, and the first parabolic reflector coincide; a pair of prisms symmetrically disposed on both sides of the disc crystal; and a pair of second parabolic reflectors located between the disc crystal and the right-angle prisms, wherein the optical axes of the pair of second parabolic reflectors coincide with the optical axis of the disc crystal, and the distance between the pair of second parabolic reflectors is less than the distance between the pair of right-angle prisms.

2. The laser amplifier based on a disk crystal according to claim 1, characterized in that, Also includes: The first reflecting mirror is located upstream of the first right-angle prism in the first pair of right-angle prisms, along the direction of light propagation.

3. The laser amplifier based on a disk crystal according to claim 2, characterized in that, Also includes: A polarizer is located upstream of the first reflector along the direction of light propagation.

4. The laser amplifier based on a disk crystal according to claim 2, characterized in that, The reflection angle of the first reflector is 45°.

5. The laser amplifier based on a disk crystal according to claim 3, characterized in that, The polarization angle of the polarizer is 56°.

6. The laser amplifier based on a disk crystal according to claim 2, characterized in that, Also includes: A λ / 4 waveplate is located downstream of the second right-angle prism that is not aligned with the right-angle prism, along the direction of light propagation, and the light-emitting surface of the second right-angle prism that is not aligned with the right-angle prism faces the λ / 4 waveplate.

7. The laser amplifier based on a disk crystal according to claim 6, characterized in that, Also includes: The second reflecting mirror is located downstream of the λ / 4 waveplate along the direction of light propagation.

8. The laser amplifier based on a disk crystal according to claim 7, characterized in that, The reflection angle of the second reflector is 0°.

9. The laser amplifier based on a disk crystal according to claim 7, characterized in that, The surfaces of the first right-angle prism, the second right-angle prism, the first reflector, the second reflector, and the first parabolic reflector are coated with a reflective film. The density of the reflective film is greater than or equal to 99.5%, and the wavelength of the light transmitted through the reflective film is 1030 nm.

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