End-pumped solid state laser

Abstract

Provided is an end-pumped solid-state laser, comprising: a picosecond seed source, a polarization isolation optical path, a pre-amplification optical path, a diffraction optical splitting optical path, and a multi-stage amplification optical path. The picosecond seed source is located at a first end of the end-pumped solid-state laser along a first direction. The polarization isolation optical path is coaxially arranged with the picosecond seed source along the first direction, and the polarization isolation optical path has a first port, a second port, and a third port: the first port is in communication with the picosecond seed source; the second port is in communication with the pre-amplification optical path; and the third port is in communication with the diffraction optical splitting optical path. The pre-amplification optical path is located on one side of the axis of the picosecond seed source and the polarization isolation optical path. The diffraction optical splitting optical path comprises an acousto-optic modulator, one end of the diffraction optical splitting optical path passes through the axis of the picosecond seed source and the polarization isolation optical path; and the other end of the diffraction optical splitting optical path is in communication with the multi-stage amplification optical path. The multi-stage amplification optical path is located on the side of the axis of the picosecond seed source and the polarization isolation optical path opposite to the pre-amplification optical path.

Description

Technical Field

[0001] This disclosure relates to the field of laser technology, and more specifically to an end-pumped solid-state laser. Background Technology

[0002] Picosecond lasers play a vital role in various fields such as medical detection, precision machining, and lidar. In industrial processing, these lasers are suitable for processing brittle and transparent materials such as sapphire and glass, as well as metal micromachining and flexible PCB board micromachining, among many other applications.

[0003] The mainstream technical routes on the market, such as Figure 1 and Figure 2 As shown, seed light is emitted from a picosecond seed source using an optical fiber seed source, and then pre-amplified (in... Figure 2 The middle section is the pre-amplification optical path 3') and multi-stage amplification (in Figure 1 and Figure 2 The example shown is a multi-stage amplification optical path 4', including a first-stage amplification optical path 41', a second-stage amplification optical path 42', and a third-stage amplification optical path 43'. Finally, an acousto-optic modulator is used to control the laser power, thereby achieving stable and adjustable laser output. Refer to the specific optical path diagram. Figure 2 The picosecond seed source 1' emits seed light, which is amplified in multiple stages by the first laser crystal 31', the second laser crystal 41b', the third laser crystal 42b', and the fourth laser crystal 43b' as gain media. Finally, the laser power is controlled by the acousto-optic modulator 51' to achieve stable and adjustable laser output.

[0004] In our experiments, we found that the diffraction efficiency of the acousto-optic modulator 51' is related not only to its own crystal characteristics and control voltage, but also to the high requirements of the incident light spot quality, including spot roundness, spot size, and spot energy distribution. For the same acousto-optic modulator 51', the diffraction efficiency difference exceeds 10% for incident lasers with different beam qualities. In multi-stage amplification optical paths, as the number of stages increases, the output optical power continuously increases, requiring more pump light power. At the same time, the quality of the high-power laser beam after multi-stage amplification continuously decreases. This places high demands on the damage threshold, optical characteristics, and diffraction efficiency of the acousto-optic modulator 51', leading to a decrease in the actual diffraction efficiency of the acousto-optic modulator 51' and easily causing unnecessary energy loss. Summary of the Invention

[0005] In view of the problems existing in the background art, one object of this disclosure is to provide an end-pumped solid-state laser that can improve the diffraction efficiency of the acousto-optic modulator while reducing the power loss of the pump light and the acousto-optic modulator.

[0006] Therefore, an end-pumped solid-state laser is provided, comprising: a picosecond seed source, a polarization isolation optical path, a pre-amplification optical path, a diffraction beam splitter optical path, and a multi-stage amplification optical path. The picosecond seed source is located at a first end of the end-pumped solid-state laser along a first direction and is used to emit seed light. The polarization isolation optical path is coaxially arranged with the picosecond seed source along the first direction and has a first port, a second port, and a third port: the first port is connected to the picosecond seed source and is used to receive the seed light emitted by the picosecond seed source; the second port is connected to the pre-amplification optical path and is used to transmit the received seed light emitted by the picosecond seed source to the pre-amplification optical path; the third port is connected to the diffraction beam splitter optical path and is used to transmit the pre-amplified seed light to the diffraction beam splitter optical path. The pre-amplification optical path is located on one side of the axis where the picosecond seed source and the polarization isolation optical path are located and is used to pre-amplify the seed light. The diffraction-splitting optical path includes an acousto-optic modulator. The diffraction-splitting optical path intersects with the first direction. One end of the diffraction-splitting optical path passes through the axis connecting the picosecond seed source and the polarization isolation optical path, and is used to receive the seed light pre-amplified by the pre-amplification optical path. The acousto-optic modulator then diffracts and splits the received pre-amplified seed light. The other end of the diffraction-splitting optical path is connected to a multi-stage amplification optical path, used to transmit the seed light after diffraction and splitting to the multi-stage amplification optical path. The multi-stage amplification optical path is located on the opposite side of the axis connecting the picosecond seed source and the polarization isolation optical path from the pre-amplification optical path, and is used to amplify the seed light after diffraction and splitting by the diffraction-splitting optical path in multiple stages.

[0007] The beneficial effects of this disclosure are as follows: Compared to the prior art, where the beam output from the pre-amplified optical path undergoes multi-stage amplification (i.e., multi-stage amplification optical path) before being transmitted to the acousto-optic modulator for modulation, the multiple amplifications require higher power pump light to ensure that the seed light, whose beam quality is continuously decreasing, can obtain the required first-order diffraction light after entering the acousto-optic modulator. This results in a requirement to increase both the power of the pump light and the power of the acousto-optic modulator. In contrast, the end-pumped solid-state laser of this disclosure directly transmits the pre-amplified seed light from the pre-amplified optical path to the diffraction beam splitter before transmitting it to the multi-stage amplification optical path for further amplification. On the one hand, this reduces the power requirement of the pump light, suppresses the spontaneous emission amplification caused by the high-power pump light entering the laser crystal in the multi-stage amplification optical path, and improves the pump light efficiency and pump utilization. On the other hand, it can reduce the power of the acousto-optic modulator, thereby improving the diffraction efficiency of the acousto-optic modulator (generally greater than 85%). As a result, the high-quality beam output from the pre-amplified optical path (generally with a spot circularity of over 95% and a small spot diameter) still maintains good spot quality after entering the acousto-optic modulator and the multi-stage amplification optical path, which is beneficial to improving the diffraction efficiency of the acousto-optic modulator (generally greater than 85%), while reducing the power loss of the acousto-optic modulator. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of an end-pumped solid-state laser based on the background technology.

[0009] Figure 2 yes Figure 1 Optical path diagram of an end-pumped solid-state laser.

[0010] Figure 3 This is a schematic diagram of an end-pumped solid-state laser based on this disclosure.

[0011] Figure 4 yes Figure 3 Optical path diagram of an end-pumped solid-state laser.

[0012] The reference numerals in the attached figures are explained as follows:

[0013] 100' end-pumped solid-state laser Q' second end

[0014] 1' Picosecond Seed Source S' Axis

[0015] 2' polarization-isolated optical path 100 end-pumped solid-state laser

[0016] P1' First Port 1 Picosecond Seed Source

[0017] P2' Second Port 2 Polarization Isolation Optical Path

[0018] P3' (third port) and P1 (first port)

[0019] 21' First half-wave plate, P2, second port

[0020] 22' First polarization isolator P3 third port

[0021] 23' Second polarization isolator 21 First half-wave plate

[0022] 24' First reflecting mirror 22 First polarizing isolator

[0023] 25' Second half-wave plate 23 Second polarization isolator

[0024] 26' Second reflecting mirror 24 First reflecting mirror

[0025] 27' Third reflecting mirror 25 Second half-wave plate

[0026] 28' Fourth reflecting mirror 26 Second reflecting mirror

[0027] 3' Pre-magnification optical path 27 Third reflecting mirror

[0028] 31' First laser crystal 28 Fourth reflecting mirror

[0029] 32'0° reflector 3 pre-magnification optical path

[0030] 33' First pump laser 31 First laser crystal

[0031] 4' Multi-stage magnification optical path 320° reflector

[0032] 41' First-stage amplification optical path 33 First-stage pump laser

[0033] 41a' Fifth reflecting mirror 4 Diffraction beam splitter path

[0034] 41b' Second laser crystal 41 Acousto-optic modulator

[0035] 41c' First dichroic mirror 42 Optical trash can

[0036] 41d' Second Pump Laser L0 Zero Order Beam

[0037] 41e' Sixth Reflector L1 First-order Diffraction Beam

[0038] 41f' Seventh Reflector 5 Multi-stage Magnification Optical Path

[0039] 42' Second-stage amplification optical path 51 First-stage amplification optical path

[0040] 42a' Eighth reflecting mirror 51a Fifth reflecting mirror

[0041] 42b' Third laser crystal, 51b Sixth reflecting mirror

[0042] 42c' second dichroic mirror; 51c first dichroic mirror

[0043] 42d' Third pump laser 51d Second laser crystal

[0044] 42e' Ninth Reflector, 51e Second Pump Laser

[0045] 42f' Tenth reflecting mirror 52 Second-stage magnifying optical path

[0046] 43' Third-stage magnifying optical path 52a Seventh reflecting mirror

[0047] 43a' Eleventh reflecting mirror; 52b Eighth reflecting mirror

[0048] 43b' Fourth laser crystal; 52c Third laser crystal

[0049] 43c' third dichroic mirror, 52d third-pump laser

[0050] 43d' Fourth pump laser 53 Third stage amplification optical path

[0051] 43e' Twelfth reflecting mirror; 53a Second dichroic mirror

[0052] 5' Diffraction Spectrophotometer 53b Third Dichroic Mirror

[0053] 51' Acousto-optic modulator, 53c fourth laser crystal

[0054] 52' Optical Trash Can 53d Fourth Pump Laser

[0055] 53' Thirteenth Reflector 6 Ninth Reflector

[0056] 54' Fourteenth Reflector 7 Tenth Reflector

[0057] 55' Fifteenth Reflector D1 First Direction

[0058] L0' Zero-order light D2 First direction

[0059] L1' First-order diffraction beam P first end

[0060] D1' First direction Q second end

[0061] D2' First direction S-axis

[0062] P' first end Detailed Implementation

[0063] The accompanying drawings illustrate embodiments of this disclosure, and it will be understood that the disclosed embodiments are merely examples of this disclosure, which can be implemented in various forms. Therefore, the specific details disclosed herein should not be construed as limiting, but are intended only as the basis for the claims and as an illustrative basis to teach those skilled in the art how to implement this disclosure in various ways.

[0064] Reference Figures 3 to 4According to the end-pumped solid-state laser 100 disclosed herein, it includes: a picosecond seed source 1, a polarization isolation optical path 2, a pre-amplification optical path 3, a diffraction beam splitter optical path 4, and a multi-stage amplification optical path 5. The picosecond seed source 1 is located at the first end P of the end-pumped solid-state laser 100 along a first direction D1 and is used to emit seed light. The polarization isolation optical path 2 is coaxially arranged with the picosecond seed source 1 along the first direction D1, and has a first port P1, a second port P2, and a third port P3: the first port P1 is connected to the picosecond seed source 1 and is used to receive the seed light emitted by the picosecond seed source 1; the second port P2 is connected to the pre-amplification optical path 3 and is used to transmit the received seed light emitted by the picosecond seed source 1 to the pre-amplification optical path 3; the third port P3 is connected to the diffraction beam splitter optical path 4 and is used to transmit the seed light pre-amplified by the pre-amplification optical path 3 to the diffraction beam splitter optical path 4. The pre-amplification optical path 3 is located on one side of the axis S where the picosecond seed source 1 and the polarization isolation optical path 2 are located, and is used to pre-amplify the seed light. The diffraction beam splitting optical path 4 includes an acousto-optic modulator 41. The diffraction beam splitting optical path 4 intersects the first direction D1. One end of the diffraction beam splitting optical path 4 passes through the axis S where the picosecond seed source 1 and the polarization isolation optical path 2 are located, and is used to receive the seed light pre-amplified by the pre-amplification optical path 3, and use the acousto-optic modulator 41 to diffract and split the received seed light pre-amplified by the pre-amplification optical path 3. The other end of the diffraction beam splitting optical path 4 is connected to the multi-stage amplification optical path 5, and is used to transmit the seed light after diffraction and splitting by the diffraction beam splitting optical path 4 to the multi-stage amplification optical path 5. The multi-stage amplification optical path 5 is located on the side of the axis S where the picosecond seed source 1 and the polarization isolation optical path 2 are located, opposite to the pre-amplification optical path 3, and is used to perform multi-stage amplification of the seed light after diffraction and splitting by the diffraction beam splitting optical path 4.

[0065] Compared to the prior art, where the beam output from the pre-amplified optical path 3' is first amplified through multiple stages (i.e., multi-stage amplification optical path 4') before being transmitted to the acousto-optic modulator 51' for modulation, the multiple amplifications require higher power pump light to ensure that the seed light, whose beam quality is continuously decreasing, can obtain the required first-order diffraction light L0' after entering the acousto-optic modulator. This results in a requirement to increase both the power of the pump light and the power of the acousto-optic modulator 51'. In contrast, the end-pumped solid-state laser 100 of this disclosure directly transmits the pre-amplified seed light from the pre-amplified optical path 3 to the diffraction beam splitter optical path 4 before transmitting it to the multi-stage amplification optical path 5 for further amplification. On the one hand, this reduces the power requirement of the pump light, suppresses the spontaneous emission amplification caused by the high-power pump light entering the laser crystal in the multi-stage amplification optical path 5, and improves the pump light efficiency and pump utilization. On the other hand, the power of the acousto-optic modulator 41 can be reduced, thereby improving the diffraction efficiency of the acousto-optic modulator 41 (generally greater than 85%). As a result, the high-quality beam output from the pre-amplified optical path 3 (generally with a spot circularity of over 95% and a small spot diameter) still maintains good spot quality after entering the acousto-optic modulator 41 and the multi-stage amplification optical path 5. This is beneficial to improving the diffraction efficiency of the acousto-optic modulator 41 (generally greater than 85%), while reducing the power loss of the acousto-optic modulator 41.

[0066] The picosecond seed source 1 disclosed herein uses an optical fiber seed source, which can be based on a SESAM saturable absorber fiber laser, or different types of seed sources can be used according to actual needs.

[0067] The polarization isolation optical path 2 includes a first half-wave plate 21, a first polarization isolator 22, a second polarization isolator 23, a first reflector 24, a second half-wave plate 25, a second reflector 26, a third reflector 27, and a fourth reflector 28 arranged sequentially. The picosecond seed source 1, the first half-wave plate 21, the first polarization isolator 22, the second polarization isolator 23, and the first reflector 24 are coaxially arranged along a first direction D1. The first reflector 24, the second half-wave plate 25, and the second reflector 26 are located at the second end Q of the end-pumped solid-state laser 100 along the first direction D1. The first half-wave plate 21 is used to adjust the polarization state of the seed light emitted by the picosecond seed source 1 so that the polarization state of the seed light is the same as that of the first polarization isolator 22. The first polarization isolator 22 is used to isolate the seed light transmitted through the first half-wave plate 21 that passes through and is isolated from the seed light that returns along the second reflector 26 and the first reflector 24 and is not isolated by the second polarization isolator 23 after being pre-amplified by the pre-amplification optical path 3. The polarization state of the second polarization isolator 23 is the same as that of the first polarization isolator 22. It is used to allow the seed light transmitted through the first half-wave plate 21 and the first polarization isolator 22 to pass through, and to deflect the propagation direction of the seed light pre-amplified by the pre-amplification optical path 3 that returns along the second reflector 26 and the first reflector 24, so that it is directed towards the third reflector 27 and the fourth reflector 28 until it enters the diffraction beam splitting optical path 4 for diffraction and beam splitting. The second half-wave plate 25 is used to adjust the polarization state of the seed light transmitted through the first half-wave plate 21, the first polarization isolator 22, and the second polarization isolator 23, so that when the seed light pre-amplified by the pre-amplification optical path 3 passes through the second half-wave plate 25 and returns to the second polarization isolator 23 via the first reflector 24, its propagation direction is deflected and it is directed entirely towards the third reflector 27, and then reflected by the third reflector 27 and the fourth reflector 28 into the diffraction beam splitting optical path 4 for diffraction and beam splitting. The seed light emitted by the picosecond seed source 1 passes through the first half-wave plate 21, the first polarization isolator 22, the second polarization isolator 23, the first reflector 24, the second half-wave plate 25, and the second reflector 26 before entering the first-stage amplification optical path 51.

[0068] The angles of the first reflector 24, the second reflector 26, the third reflector 27, and the fourth reflector 28 are adjustable, which is beneficial for achieving spot pattern matching.

[0069] The first reflector 24, the second reflector 26, the third reflector 27, and the fourth reflector 28 are 45° reflectors.

[0070] In the pre-amplification optical path 3 and the multi-stage amplification optical path 5, the pump light and the corresponding seed light in the laser crystal achieve mode matching. Their transmission directions can be either in the same direction or opposite directions. In-direction transmission is beneficial for improving amplification efficiency, while opposite transmission can reduce the amplification of spontaneous emission generated by the crystal itself. The choice can be made based on actual needs during the actual setup process.

[0071] In practical applications, the choice between single-pass and double-pass amplification of the pre-amplification optical path 3 can be determined based on the required laser power parameters. In one embodiment of this disclosure, referring to... Figure 4 The pre-amplification optical path 3 is a two-way amplification optical path. In another embodiment of this disclosure (not shown), the pre-amplification optical path 3 is a single-way amplification optical path.

[0072] The pre-amplification optical path 3 includes a first laser crystal 31, a 0° reflector 32, and a first pump laser 33 that provides the first pump light, arranged sequentially. The first laser crystal 31 and the first pump laser 33 are coaxially arranged along the first direction D1. The first pump laser 33 is located at the first end P of the end-pump solid-state laser 100 along the first direction D1. The first pump light emitted by the first pump laser 33 passes through the 0° reflector 32 and enters the first laser crystal 31. The first pump light is coaxially transmitted with the seed light emitted by the picosecond seed source 1 of the first laser crystal 31, which passes through the first half-wave plate 21, the first polarization isolator 22, the second polarization isolator 23, the first reflector 24, the second half-wave plate 25, and the second reflector 26 and enters the first-stage amplification optical path 51.

[0073] The 0° reflector 32 can be a 0° pump high-transmittance laser high-reflection dichroic mirror. One side of the 0° reflector 32 is coated with an anti-reflection film to allow all pump light to pass through, while the other side is coated with a high-reflection film to allow all seed beam to be reflected.

[0074] The diffraction-splitting optical path 4 also includes an optical bin 42. The fourth reflecting mirror 28, the acousto-optic modulator 41, and the optical bin 42 are coaxially arranged along a second direction D2 intersecting the first direction D1. The acousto-optic modulator 41 is used to diffract and split the seed light, which has been pre-amplified by the pre-amplification optical path 3 via the second reflecting mirror 26, the first reflecting mirror 24, the second polarization isolator 23, the third reflecting mirror 27, and the fourth reflecting mirror 28, to obtain the zero-order light L0 and the first-order diffracted light L1. The optical bin 42 is used to receive the zero-order light L0 after diffraction and splitting by the acousto-optic modulator 41. The first-order diffracted light L1 after diffraction and splitting by the acousto-optic modulator 41 enters the first-stage amplification optical path 51.

[0075] Considering that the acousto-optic modulator 41 has high requirements for the beam quality of the incident light entering it, refer to Figure 4 The optical path between the acousto-optic modulator 41 and the second polarization isolator 23 needs to be shortened as much as possible, which is beneficial to improving the diffraction efficiency of the acousto-optic modulator 41. At the same time, since the angle between the zero-order light L0 and the first-order diffracted light L1 obtained by diffraction is small, the optical bin 42 needs to maintain a predetermined distance relative to the acousto-optic modulator 41 so that the zero-order light L0 and the first-order diffracted light L1 can be easily separated.

[0076] In practical applications, the number of stages in the multi-stage amplification optical path and whether to use single-pass or double-pass amplification can be determined based on the required laser power parameters.

[0077] Any one of the amplification optical paths in the multi-stage amplification optical path 5 is a single-pass amplification optical path or a double-pass amplification optical path.

[0078] In one embodiment of this disclosure, reference is made to... Figure 4 The multi-stage amplification optical path 5 is a three-stage amplification optical path. The multi-stage amplification optical path 5 includes a first-stage amplification optical path 51 for first-stage amplification, a second-stage amplification optical path 52 for second-stage amplification, and a third-stage amplification optical path 53 for third-stage amplification.

[0079] The multi-stage amplification optical path 5 includes multiple pump lasers, which are located at the first end P of the end-face pump solid-state laser 100 along the first direction D1.

[0080] Reference Figure 4 The multi-stage amplification optical path 5 is a three-stage amplification optical path, all of which are single-pass amplification optical paths. Since the structures of the first-stage amplification optical path 51, the second-stage amplification optical path 52, and the third-stage amplification optical path 53 are very similar, and the pump lasers of each stage are placed on the same side of the laser, the amplification optical path and the space occupied are greatly simplified, reducing the difficulty of optical path adjustment. At the same time, because the structures of the first-stage amplification optical path 51, the second-stage amplification optical path 52, and the third-stage amplification optical path 53 are very similar, this also provides design space for the aforementioned optical trash can 42 and acousto-optic modulator 41 to maintain a certain distance. The optical path between the optical trash can 42 and the acousto-optic modulator 41 can pass through the first-stage amplification optical path 51, the second-stage amplification optical path 52, and the third-stage amplification optical path 53 of the multi-stage amplification optical path 5, instead of being as described in the reference... Figure 2 Similar to the multi-stage amplification optical path 4' of the end-pumped solid-state laser 100', the optical bin 52' and the acousto-optic modulator 51' need to be placed at the edge of the end-pumped solid-state laser 100', and the required optical path can only be met by reflection through the thirteenth mirror 53' to separate the zero-order light L0' and the first-order diffracted light L1'. However, this design will require the addition of a fourteenth mirror 54' between the optical bin 52' and the acousto-optic modulator 51', and will also require additional space occupied by the optical bin 52'. At the same time, it is inevitable that the zero-order light L0' will be attenuated because it is not directly absorbed by the optical bin 52' but passes through the fourteenth mirror 54'. The attenuated part of the zero-order light L0' propagating in the end-pumped solid-state laser 100' will affect the normal optical path, thereby affecting the stability of the normal operation of the end-pumped solid-state laser 100' and the quality of the output first-order diffracted light L1'.

[0081] The first-stage amplification optical path 51 includes a fifth reflecting mirror 51a, a sixth reflecting mirror 51b, a first dichroic mirror 51c, a second laser crystal 51d, and a second pump laser 51e arranged sequentially. The first-stage diffracted light L1, after being diffracted and split by the acousto-optic modulator 41, enters the fifth reflecting mirror 51a of the first-stage amplification optical path 51. The seed light emitted from the picosecond seed source 1 passes through a first half-wave plate 21, a first polarization isolator 22, a second polarization isolator 23, a first reflecting mirror 24, a second half-wave plate 25, and a second reflecting mirror 26, and enters the second laser crystal 51d of the first-stage amplification optical path 51. The first dichroic mirror 51c, the second laser crystal 51d, and the second pump laser 51e are coaxially arranged along the first direction D1. The second pump laser 51e is located at the first end P of the end-pumped solid-state laser 100 along the first direction D1, and the fifth reflecting mirror 51a is located at the second end Q of the end-pumped solid-state laser 100 along the first direction D1. The second pump laser 51e provides the second pump light. The second pump light emitted by the second pump laser 51e passes through the first dichroic mirror 51c and enters the second laser crystal 51d. The second pump light is coaxially transmitted with the first-order diffracted light L1, which is transmitted through the fifth mirror 51a, the sixth mirror 51b, and the first dichroic mirror 51c and is directed to the second laser crystal 51d by the acousto-optic modulator 41.

[0082] The angles of the fifth reflecting mirror 51a and the sixth reflecting mirror 51b are adjustable, which is beneficial for achieving spot pattern matching.

[0083] The fifth reflecting mirror 51a and the sixth reflecting mirror 51b are 45° reflecting mirrors.

[0084] The second-stage amplification optical path 52 includes a seventh reflecting mirror 52a, an eighth reflecting mirror 52b, a third laser crystal 52c, and a third pump laser 52d arranged sequentially. The third laser crystal 52c and the third pump laser 52d are coaxially arranged along a first direction D1. The third pump laser 52d is located at the first end P of the end-pumped solid-state laser 100 along the first direction D1, and the seventh reflecting mirror 52a and the eighth reflecting mirror 52b are located at the second end Q of the end-pumped solid-state laser 100 along the first direction D1. The third pump laser 52d provides the third pump light. The third pump light emitted by the third pump laser 52d passes through and enters the third laser crystal 52c, and the third pump light is coaxially transmitted with the seed light amplified by the first stage of the first-stage amplification optical path 51, which is transmitted through the seventh reflecting mirror 52a and the eighth reflecting mirror 52b to the third laser crystal 52c.

[0085] The angles of the seventh reflecting mirror 52a and the eighth reflecting mirror 52b are adjustable, which is beneficial for achieving spot pattern matching.

[0086] The seventh reflecting mirror 52a and the eighth reflecting mirror 52b are 45° reflecting mirrors.

[0087] The third-stage amplification optical path 53 includes a second dichroic mirror 53a, a third dichroic mirror 53b, a fourth laser crystal 53c, and a fourth pump laser 53d arranged sequentially. The second dichroic mirror 53a is coaxially arranged with the third laser crystal 52c and the third pump laser 52d along a first direction D1; the third pump light emitted by the third pump laser 52d passes through the second dichroic mirror 53a and enters the third laser crystal 52c. The fourth pump laser 53d, the third dichroic mirror 53b, and the fourth laser crystal 53c are coaxially arranged along the first direction D1, and the fourth pump laser 53d is located at the first end P of the end-pumped solid-state laser 100 along the first direction D1. The fourth pump laser 53d provides the fourth pump light. The fourth pump light emitted by the fourth pump laser 53d passes through the third dichroic mirror 53b and enters the fourth laser crystal 53c. The fourth pump light is coaxially transmitted with the seed light, which is amplified by the second-stage amplification optical path 52 and transmitted to the fourth laser crystal 53c through the second dichroic mirror 53a and the third dichroic mirror 53b.

[0088] In one example, refer to Figure 2 The end-pumped solid-state laser 100 also includes a ninth mirror 6 and a tenth mirror 7, which are located at the second end Q of the end-pumped solid-state laser 100 near the first direction D1 in the third-stage amplification optical path 53, and are used to output the seed light amplified by the multi-stage amplification optical path 5 from the output port (not shown).

[0089] Reference Figure 2 and Figure 4 Compared to the multi-stage amplification optical path 4' of the end-pumped solid-state laser 100' in the prior art, the multi-stage amplification optical path 5 of the end-pumped solid-state laser 100 disclosed herein has four fewer mirrors, thus reducing transmission loss.

[0090] The angles of the ninth reflector 6 and the tenth reflector 7 are adjustable.

[0091] The ninth reflector 6 and the tenth reflector 7 are 45° reflectors.

[0092] The end-pumped solid-state laser 100 provided in this disclosure adopts a solid-state amplification structure. The signal light and pump light need to achieve strict mode matching at each stage of the laser crystal. The signal light and pump light can be beam shaped by shaping elements (such as refractive optical elements or diffractive optical elements) so that the beam waist position of both is focused at the laser crystal, thereby achieving a high degree of mode matching.

[0093] Several exemplary embodiments have been described in detail above, but this document is not intended to limit itself to the explicitly disclosed combinations. Therefore, unless otherwise stated, the various features disclosed herein can be combined to form several other combinations, which are not shown for simplicity.

Claims

1. An end-pumped solid-state laser, characterized in that, include: Picosecond seed source (1), polarization isolation optical path (2), pre-amplification optical path (3), diffraction beam splitting optical path (4), and multi-stage amplification optical path (5), The picosecond seed source (1) is located at the first end (P) of the end-pumped solid-state laser (100) along the first direction (D1) and is used to emit seed light; The polarization isolation optical path (2) and the picosecond seed source (1) are coaxially arranged along the first direction (D1). The polarization-isolated optical path (2) has a first port (P1), a second port (P2), and a third port (P3): The first port (P1) is connected to the picosecond seed source (1) and is used to receive the seed light emitted by the picosecond seed source (1); The second port (P2) is connected to the pre-amplified optical path (3) and is used to transmit the seed light emitted by the receiving picosecond seed source (1) to the pre-amplified optical path (3); The third port (P3) is connected to the diffraction beam splitting optical path (4) and is used to transmit the seed light pre-amplified by the pre-amplification optical path (3) to the diffraction beam splitting optical path (4); The pre-amplification optical path (3) is located on one side of the axis (S) where the picosecond seed source (1) and the polarization isolation optical path (2) are located, and is used to pre-amplify the seed light; The diffraction beam splitting optical path (4) includes an acousto-optic modulator (41). The diffraction beam splitting optical path (4) intersects with the first direction (D1). One end of the diffraction beam splitting optical path (4) passes through the axis (S) where the picosecond seed source (1) and the polarization isolation optical path (2) are located. It is used to receive the seed light pre-amplified by the pre-amplification optical path (3) and to use the acousto-optic modulator (41) to diffract and split the received seed light pre-amplified by the pre-amplification optical path (3). The other end of the diffraction beam splitting optical path (4) is connected to the multi-stage amplification optical path (5) to transmit the first-stage diffracted light (L1) after diffraction and beam splitting by the diffraction beam splitting optical path (4) to the multi-stage amplification optical path (5); The multi-stage amplification optical path (5) is located on the opposite side of the axis (S) between the picosecond seed source (1) and the polarization isolation optical path (2) to the pre-amplification optical path (3), and is used to amplify the seed light after it has been diffracted and split by the diffraction and splitting optical path (4) in multiple stages.

2. The end-pumped solid-state laser according to claim 1, characterized in that, The multi-stage amplification optical path (5) is a three-stage amplification optical path.

3. The end-pumped solid-state laser according to claim 2, characterized in that, The multi-stage amplification optical path (5) includes a first-stage amplification optical path (51) for first-stage amplification, a second-stage amplification optical path (52) for second-stage amplification, and a third-stage amplification optical path (53) for third-stage amplification.

4. The end-pumped solid-state laser according to claim 3, characterized in that, The polarization isolation optical path (2) includes a first half-wave plate (21), a first polarization isolator (22), a second polarization isolator (23), a first reflector (24), a second half-wave plate (25), a second reflector (26), a third reflector (27), and a fourth reflector (28) arranged sequentially. The picosecond seed source (1), the first half-wave plate (21), the first polarization isolator (22), the second polarization isolator (23), and the first reflector (24) are coaxially arranged along the first direction (D1). The first reflector (24), the second half-wave plate (25), and the second reflector (26) are located at the second end (Q) of the end-pumped solid-state laser (100) along the first direction (D1). The first half-wave plate (21) is used to adjust the polarization state of the seed light emitted by the picosecond seed source (1) so that the polarization state of the seed light is the same as that of the first polarization isolator (22). The first polarization isolator (22) is used to pass through the seed light transmitted through the first half-wave plate (21) and to isolate the seed light that returns along the second mirror (26) and the first mirror (24) and is not isolated by the second polarization isolator (23) after being pre-amplified by the pre-amplified optical path (3); The polarization state of the second polarization isolator (23) is the same as that of the first polarization isolator (22). It is used to allow the seed light transmitted through the first half-wave plate (21) and the first polarization isolator (22) to pass through, and to deflect the propagation direction of the seed light that returns along the second mirror (26) and the first mirror (24) after being pre-amplified by the pre-amplification optical path (3) and direct it toward the third mirror (27) and the fourth mirror (28) until it enters the diffraction beam splitting optical path (4) for diffraction beam splitting. The second half-wave plate (25) is used to adjust the polarization state of the seed light transmitted through the first half-wave plate (21), the first polarization isolator (22), and the second polarization isolator (23), so that when the seed light pre-amplified by the pre-amplification optical path (3) passes through the second half-wave plate (25) and returns to the second polarization isolator (23) through the first reflecting mirror (24), the propagation direction is deflected and all of it is directed toward the third reflecting mirror (27), and then reflected by the third reflecting mirror (27) and the fourth reflecting mirror (28) into the diffraction beam splitting optical path (4) for diffraction beam splitting; The seed light emitted by the picosecond seed source (1) passes through the first half-wave plate (21), the first polarization isolator (22), the second polarization isolator (23), the first mirror (24), the second half-wave plate (25), and the second mirror (26) and enters the first-stage amplification optical path (51).

5. The end-pumped solid-state laser according to claim 4, characterized in that, The pre-amplification optical path (3) includes a first laser crystal (31), a 0° reflector (32), and a first pump laser (33) that provides the first pump light, arranged in sequence. The first laser crystal (31) and the first pump laser (33) are coaxially arranged along the first direction (D1). The first pump laser (33) is located at the first end (P) of the end face pump solid laser (100) along the first direction (D1). The first pump light emitted by the first pump laser (33) passes through the 0° reflector (32) and enters the first laser crystal (31). The first pump light is coaxially transmitted with the seed light emitted by the picosecond seed source (1) of the first laser crystal (31) that passes through the first half-wave plate (21), the first polarization isolator (22), the second polarization isolator (23), the first reflector (24), the second half-wave plate (25), and the second reflector (26) and enters the first stage amplification optical path (51).

6. The end-pumped solid-state laser according to claim 4, characterized in that, The diffraction beam splitter (4) also includes an optical trash can (42), a fourth reflecting mirror (28), an acousto-optic modulator (41), and the optical trash can (42) is coaxially arranged along a second direction (D2) intersecting the first direction (D1). The acousto-optic modulator (41) is used to diffract and separate the seed light after it has been pre-amplified by the pre-amplified optical path (3) transmitted to the acousto-optic modulator (41) via the second mirror (26), the first mirror (24), the second polarization isolator (23), the third mirror (27), and the fourth mirror (28), to obtain the zero-order light (L0) and the first-order diffracted light (L1). The optical trash can (42) is used to receive the zero-order light (L0) after diffraction by the acousto-optic modulator (41). The first-stage diffracted light (L1) after being diffracted and split by the acousto-optic modulator (41) is injected into the first-stage amplification optical path (51).

7. The end-pumped solid-state laser according to claim 6, characterized in that, The first-stage amplification optical path (51) includes a fifth reflecting mirror (51a), a sixth reflecting mirror (51b), a first dichroic mirror (51c), a second laser crystal (51d), and a second pump laser (51e) arranged sequentially. The first-stage diffracted light (L1) after being diffracted and split by the acousto-optic modulator (41) enters the fifth reflecting mirror (51a) of the first-stage amplification optical path (51); The seed light emitted by the picosecond seed source (1) passes through the first half-wave plate (21), the first polarization isolator (22), the second polarization isolator (23), the first mirror (24), the second half-wave plate (25), and the second mirror (26) and enters the second laser crystal (51d) of the first-stage amplification optical path (51); The first dichroic mirror (51c), the second laser crystal (51d), and the second pump laser (51e) are coaxially arranged along the first direction (D1). The second pump laser (51e) is located at the first end (P) of the end-pumped solid-state laser (100) along the first direction (D1), and the fifth reflector (51a) is located at the second end (Q) of the end-pumped solid-state laser (100) along the first direction (D1). The second pump laser (51e) provides the second pump light. The second pump light emitted by the second pump laser (51e) passes through the first dichroic mirror (51c) and enters the second laser crystal (51d). The second pump light is coaxially transmitted with the first-order diffracted light (L1) that is transmitted to the second laser crystal (51d) by the acousto-optic modulator (41) through the fifth mirror (51a), the sixth mirror (51b), and the first dichroic mirror (51c).

8. The end-pumped solid-state laser according to claim 7, characterized in that, The second-stage amplification optical path (52) includes a seventh reflecting mirror (52a), an eighth reflecting mirror (52b), a third laser crystal (52c), and a third pump laser (52d) arranged sequentially. The third laser crystal (52c) and the third pump laser (52d) are coaxially arranged along the first direction (D1). The third pump laser (52d) is located at the first end (P) of the end-pumped solid-state laser (100) along the first direction (D1). The seventh mirror (52a) and the eighth mirror (52b) are located at the second end (Q) of the end-pumped solid-state laser (100) along the first direction (D1). The third pump laser (52d) provides the third pump light. The third pump light emitted by the third pump laser (52d) is incident on the third laser crystal (52c), and the third pump light is coaxially transmitted with the seed light, which is amplified by the first stage amplification optical path (51) and transmitted to the third laser crystal (52c) through the seventh mirror (52a) and the eighth mirror (52b).

9. The end-pumped solid-state laser according to claim 8, characterized in that, The third-stage amplification optical path (53) includes a second dichroic mirror (53a), a third dichroic mirror (53b), a fourth laser crystal (53c), and a fourth pump laser (53d) arranged sequentially. The second dichroic mirror (53a), the third laser crystal (52c), and the third pump laser (52d) are coaxially arranged along the first direction (D1); The third pump light emitted by the third pump laser (52d) enters the third laser crystal (52c) through the second dichroic mirror (53a); The fourth pump laser (53d), the third dichroic mirror (53b), and the fourth laser crystal (53c) are coaxially arranged along the first direction (D1). The fourth pump laser (53d) is located at the first end (P) of the end-pumped solid-state laser (100) along the first direction (D1). The fourth pump laser (53d) provides the fourth pump light. The fourth pump light emitted by the fourth pump laser (53d) passes through the third dichroic mirror (53b) and enters the fourth laser crystal (53c). The fourth pump light is coaxially transmitted with the seed light, which is amplified twice by the second-stage amplification optical path (52) and transmitted to the fourth laser crystal (53c) through the second dichroic mirror (53a) and the third dichroic mirror (53b).

10. The end-pumped solid-state laser according to claim 3, characterized in that, include: It also includes a ninth mirror (6) and a tenth mirror (7), which are located at the second end (Q) of the pump solid-state laser (100) near the end face of the third-stage amplification optical path (53) along the first direction (D1), and are used to output the seed light amplified by the multi-stage amplification optical path (5) from the output port (not shown).

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