CN219892606U - 2.1 mu m wave band holmium slat laser amplifier - Google Patents

Abstract

The utility model relates to the technical field of solid laser, and provides a 2.1 mu m wave band holmium slat laser amplifier for amplifying 2.1 mu m seed laser; comprising the following steps: a thulium laser resonator; the transmission direction of the seed laser with the diameter of 2.1 μm is perpendicular to the transmission direction of the thulium laser; the bonding plate bar gain medium is arranged in the thulium laser resonant cavity; the laser comprises a first thulium-doped part and a holmium-doped part, wherein the first thulium-doped part and the holmium-doped part are sequentially arranged along the transmission direction of thulium laser; the thulium laser advances in the key plate bar gain medium in an Zigzag optical path, and forms feedback oscillation of the thulium laser in the thulium laser resonant cavity; and the pump source generates pump light which is shaped and then is coupled with the bonding plate bar gain medium. The utility model can realize the amplification of the high-power high-beam-quality 2.1 mu m laser, avoid the first thulium doped part of the holmium laser with serious thermal effect, and solve the problems of high-power intracavity pumping and low thermal distortion amplification.

Description

2.1 mu m wave band holmium slat laser amplifier

Technical Field

The utility model relates to the technical field of solid laser, in particular to a holmium slab laser amplifier with a wave band of 2.1 mu m.

Background

All-solid-state thulium (Tm) lasers and holmium (Ho) lasers are the main lasing media for obtaining 2 μm band lasers. For thulium lasers, mature 790nm band semiconductor lasers can be used for pumping to obtain lasers with wavelengths of 1.9-2.0 μm, but wavelengths are difficult to tune to above 2.1 μm. The holmium-doped laser medium can realize 2.1 mu m laser output, but has no pumping absorption band near 800nm, mainly adopts 1.9 mu m-2.0 mu m in-band pumping, for example, a 1.9 mu m thulium fiber laser or a 1.9 mu m semiconductor laser can be adopted for pumping, but the pumping light of the 1.9 mu m wave band is expensive, and the power is lower. And because the holmium laser medium has smaller absorption coefficient of 1.9-2.0 mu m, a long crystal absorption length is needed to be absorbed effectively, which causes difficulty in use.

The adoption of thulium laser intracavity pump holmium laser is also a technical scheme for generating 2.1 mu m wave band laser, and the effective absorption of pump light can be realized only by 10% of one-way absorption of thulium laser with the wavelength of 1.9-2.0 mu m in the cavity by the holmium laser medium in the scheme.

The currently reported intra-cavity pumping schemes are divided into coaxial intra-cavity pumping and side intra-cavity pumping. In the coaxial cavity pumping scheme, a thulium doped crystal rod and a holmium doped crystal rod are sequentially arranged, a 790nm semiconductor laser pumps the thulium laser rod, 1.9-2.0 mu m laser oscillation is generated but not output, the holmium doped crystal rod is pumped in the cavity, 2.1 mu m holmium laser is generated in the same resonant cavity oscillation and output from the cavity, obviously 2.1 mu m holmium laser still passes through the thulium crystal rod, the thermal effect of the thulium crystal rod is very serious, the thermal distortion of the thulium doped crystal rod also causes the light beam quality deterioration to the 2.1 mu m holmium laser, and high power output is difficult to realize. In the side cavity pumping scheme, a thulium-doped slab laser oscillator generates thulium laser with the wavelength of 1.9-2.0 mu m, holmium slab crystals are arranged in the thulium laser oscillator to pump from the side, the optical axis direction of the holmium laser oscillator is perpendicular to that of the thulium laser oscillator, namely, the generated 2.1 mu m holmium laser only passes through the holmium-doped laser crystal and cannot pass through the thulium-doped laser crystal. Because the holmium-doped laser crystal is in-band pumping, the waste heat is very little, and the thermal distortion is very small, the side cavity pumping mode can effectively improve the beam quality of the cavity pumping holmium laser and improve the output power, but the power which can be realized by the crystal rod structure which is adopted in the past is limited.

However, in the slab cavity pumping scheme in the prior art, most of the slab cavity pumping scheme is based on coaxial oscillation of thulium and holmium lasers, and the output holmium lasers need to pass through a thulium-doped region with serious thermal effect to cause thermal distortion of the lasers.

Disclosure of Invention

The utility model provides a 2.1-mu m-band holmium slab laser amplifier, which is used for solving the defect that the output holmium laser is required to pass through a thulium-doped region with serious thermal effect to cause thermal distortion of the laser in a side cavity pumping scheme in the prior art, and realizing amplification of 2.1-mu m laser with high efficiency and high beam quality.

The utility model provides a 2.1 mu m wave band holmium slat laser amplifier, which is used for amplifying 2.1 mu m seed laser and comprises the following components: the thulium laser resonant cavity is used for emitting thulium laser; the transmission direction of the thulium laser is perpendicular to the transmission direction of the 2.1 mu m seed laser;

the bonding plate bar gain medium is arranged in the thulium laser resonant cavity; the laser device comprises a first thulium doped part and a holmium doped part, wherein the first thulium doped part and the holmium doped part are sequentially arranged along the transmission direction of thulium laser; the thulium laser advances in the key plate bar gain medium in a Zigzag optical path, and forms feedback oscillation of the thulium laser in the thulium laser resonant cavity;

the pump source generates pump light and couples the bonding plate bar gain medium after shaping;

the holmium doped part is used for vertically passing through the 2.1 mu m seed laser so as to amplify the 2.1 mu m seed laser.

According to the 2.1-mu m-band holmium slab laser amplifier provided by the utility model, the thulium laser resonant cavity is provided with two cavity mirrors; and the cavity mirrors are all plated with high-reflection films for reflecting 1.9-2.0 mu m thulium laser.

According to the 2.1 μm-band holmium slab laser amplifier provided by the utility model, the bonding plate slab gain medium further comprises: the second thulium doped part, the first undoped part and the second undoped part, and the first thulium doped part, the first undoped part, the holmium doped part, the second undoped part and the second thulium doped part are sequentially arranged.

According to the holmium slat laser amplifier with the wave band of 2.1 mu m, the side surface of the holmium doped part parallel to the thulium laser transmission direction is a polished surface and is plated with a 2.1 mu m laser antireflection film; the side surface of the first thulium doped part parallel to the thulium laser transmission direction is a texturing surface.

According to the 2.1-mu m-band holmium slab laser amplifier provided by the utility model, the matrix of the bonding plate slab gain medium is one of YAG crystal, YLF crystal, YVO4 crystal, YAP crystal and YAG ceramic.

According to the holmium slab laser amplifier with the wave band of 2.1 mu m, the thickness of the gain medium of the key slab is 1mm-10mm, the width is 5mm-50mm, and the length is 30mm-200mm.

According to the holmium slab laser amplifier with the wave band of 2.1 mu m, the side surface of the key slab gain medium, which is close to the 2.1 mu m seed laser, is a first side surface, and the plane opposite to the first side surface is a second side surface; the plane formed by the key plate strip gain medium along the length direction and the width direction is a large surface;

an included angle of 30-60 degrees is formed between the first side face and the large face and between the second side face and the large face; the 2.1 mu m seed laser is injected into the holmium doped part from the first side surface, advances in the holmium doped part in an Zigzag optical path, and forms feedback oscillation of thulium laser in the thulium laser resonant cavity.

According to the holmium slab laser amplifier with the wave band of 2.1 mu m, the side surface of the slab gain medium of the key plate, which is close to the cavity mirror, is a first end surface and a second end surface, and an oblique angle of 45 degrees is formed between the first end surface and the large surface and between the second end surface and the large surface; the first end face and the second end face are used for reflecting the pump light into the bonding plate bar gain medium to pump the first thulium doped part and the second thulium doped part.

According to the holmium slab laser amplifier with the wave band of 2.1 mu m, the amplification number of the 2.1 mu m seed laser in the holmium doped part is multiple, and the seed laser is folded and travels through the reflecting mirror.

According to the holmium slat laser amplifier with the wave band of 2.1 mu m provided by the utility model, the gain medium of the key plate bar is welded and fixed with the crystal heat sink by taking the large surface as the contact surface.

According to the 2.1-mu m-band holmium strip laser amplifier, thulium laser is emitted through the thulium laser resonant cavity, and the thulium-holmium laser medium bonding plate strip laser amplifier is adopted, so that kilowatt level and higher power can be realized; thulium laser advances with Zigzag light path in the gain medium of bonding board strip, because its gain medium is the lath shape, carries out the heat dissipation through two big faces of lath, consequently can realize better thermal management than bar-shaped gain medium, and thulium laser advances with Zigzag light path in the lath inside, can compensate the first order thermal effect of lath thickness direction, avoids thermal lens focusing effect, consequently can realize the laser output that is higher than bar-shaped laser by several orders of magnitude. The thulium doped part and the holmium doped part laser medium are combined into the Zigzag slat structure, and the 2.1 mu m high-power laser output can be realized through an intracavity pumping mode. The feedback oscillation of thulium laser is formed in the thulium laser resonant cavity, the pump source generates pump light to be shaped and then is coupled with the key plate bar gain medium, the transmission direction of 2.1 mu m seed laser is perpendicular to the transmission direction of thulium laser to realize side pumping, and 2.1 mu m seed laser passes through the holmium doped part to be amplified; the thulium-doped part of holmium laser with serious thermal effect can be avoided, and the thermal distortion of holmium laser is reduced as much as possible.

Drawings

In order to more clearly illustrate the utility model or the technical solutions of the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the utility model, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of the transmission of thulium laser light from a 2.1 μm band holmium slab laser amplifier according to one embodiment of the present utility model;

FIG. 2 is a schematic diagram of the structure of a pump holmium laser of a 2.1 μm band holmium slab laser amplifier according to one embodiment of the utility model;

FIG. 3 is a schematic diagram of the transmission of thulium laser light from a 2.1 μm band holmium slab laser amplifier in accordance with yet another embodiment of the present utility model;

FIG. 4 is a schematic diagram of the structure of a pump holmium laser of a 2.1 μm band holmium slab laser amplifier according to yet another embodiment of the utility model;

FIG. 5 is a pump holmium laser of a 2.1 μm band holmium slab laser amplifier according to a further embodiment of the utility model

Fig. 6 is a schematic diagram of the structure of a pump holmium laser of a 2.1 μm band holmium slab laser amplifier according to another embodiment of the utility model.

Reference numerals:

1. 2.1 μm seed laser; 2. a key plate bar gain medium; 21. a first thulium doped moiety; 22. a second thulium doped moiety; 23. a holmium doped moiety; 24. a first undoped portion; 25. a second undoped portion; 3. a crystalline heat sink; 4. a pump source; 41. pump light; 5. a thulium laser resonator; 51. thulium laser; 52. a cavity mirror; 61. a first end face; 62. a second end face; 7. a first side; 72. a holmium doped region on the first side; 8. a second side; 82. a second side holmium doped region; 9. a reflecting mirror; 10. a wave plate; 11. a polarizing plate.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present utility model more apparent, the technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In the description of the embodiments of the present utility model, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the embodiments of the present utility model and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the embodiments of the present utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The 2.1 μm band holmium slab laser amplifier of the present utility model is described below with reference to fig. 1 to 6.

As shown in fig. 1 and fig. 2, the embodiment of the utility model provides a 2.1 μm band holmium slab laser amplifier for amplifying 2.1 μm seed laser 1, which comprises a bonding plate slab gain medium 2, a pump source 4 and a thulium laser resonant cavity 5, wherein the thulium laser resonant cavity 5 is used for emitting thulium laser 51, and the transmission direction of the thulium laser 51 is perpendicular to the transmission direction of the 2.1 μm seed laser; the bonding plate bar gain medium 2 is arranged in the thulium laser resonant cavity 5; the bonding plate bar gain medium 2 comprises a first thulium doped part 21 and a holmium doped part 23, and the first thulium doped part 21 and the holmium doped part 23 are sequentially arranged along the transmission direction of the thulium laser 51; the thulium laser 51 travels in a Zigzag optical path in the bonding plate bar gain medium 2, and forms feedback oscillation of the thulium laser 51 in the thulium laser resonant cavity 5; the pump source 4 generates pump light and couples the bonding plate bar gain medium 2 after shaping; the transmission direction of the 2.1 μm seed laser 1 is perpendicular to the transmission direction of the thulium laser 51 to realize side pumping, and the holmium doped part 23 is used for allowing the 2.1 μm seed laser 1 to vertically pass through so as to realize the amplification of 2.1 μm gravity laser, so that the holmium laser can be prevented from passing through the first thulium doped part 21 with serious thermal effect, and the thermal distortion of the holmium laser can be reduced as much as possible.

The gain medium 2 of the bonding plate bar is welded on the crystal heat sink 3 made of copper material in a large-surface welding mode, and is arranged on the crystal heat sink 3 in a large-surface sealing and soaking mode in refrigerating fluid.

In one embodiment of the utility model, the thulium laser resonator 5 has two mirrors 52; and the cavity mirror 52 is plated with a high-reflection film for reflecting 1.9-2.0 mu m thulium laser, and the reflectivity of the high-reflection film for the 1.9-2.0 mu m wave band is more than 99%.

In one embodiment of the present utility model, the key plate bar gain medium 2 further comprises: the second thulium doped part 22, the first undoped part 24 and the second undoped part 25, and the first thulium doped part 21, the first undoped part 24, the holmium doped part 23, the second undoped part 25 and the second thulium doped part 22 are sequentially arranged. Since the crystals of the first thulium doped part 21 and the second thulium doped part 22 absorb 790nm semiconductor laser, the thermal distortion is large, the crystals of the thulium doped part 23 absorb 1.9-2.0 μm band thulium laser, the thermal effect is small, the bonding between the two can cause thermal expansion mutation of the bonding surface, the thermal distortion is large near the bonding surface, the first undoped part 24 is arranged between the first thulium doped part 21 and the thulium doped part 23, the second undoped part 25 is arranged between the second thulium doped part 22 and the thulium doped part 23, the influence of the thermal effect of the crystals of the first thulium doped part 21 or the second thulium doped part 22 on the holmium doped part 23 can be avoided, and the thermal distortion is reduced.

In one embodiment of the present utility model, the matrix of the bond bar gain medium 2 is one of YAG crystal, YLF crystal, YVO4 crystal, YAP crystal, YAG ceramic. The key plate bar gain medium 2 may be selected according to the requirements and is not particularly limited herein.

In one embodiment of the present utility model, the key plate bar gain media 2 has a thickness of 1mm-10mm, a width of 5mm-50mm, and a length of 30mm-200mm. The size of the key plate bar gain medium 2 can be set according to the requirement.

In one embodiment of the utility model, the side of the key plate bar gain medium 2 near the 2.1 μm seed laser 1 is a first side 7 and the plane opposite the first side 7 is a second side 8; the plane formed by the key plate bar gain medium 2 along the length direction and the width direction is a large surface; an included angle of 30-60 degrees is formed between the first side surface 7, the second side surface 8 and the large surface; the 2.1 μm seed laser 1 is injected into the holmium doped section 23 from the first side 7 and travels in an Zigzag optical path inside the holmium doped section 23 until exiting from the second side 8.

In one embodiment of the present utility model, the side surface of the holmium doped portion 23 parallel to the thulium laser transmission direction is a polished surface, that is, the first side surface 7 is polished at the holmium doped portion 23 and is optically polished, so as to ensure that the holmium laser smoothly passes through the holmium doped portion 23 of the bonding plate bar gain medium 2. The first side surface 7 is plated with an antireflection film for 2.1 mu m laser in the holmium doped part 23, so that the laser can pass through conveniently; the regions of the first thulium doped portion 21 and the second thulium doped portion 22 of the first side 7 are roughened surfaces to avoid holmium laser passing through the first thulium doped portion 21 or the second thulium doped portion 22.

In one embodiment of the present utility model, the sides of the key plate bar gain medium 2 near the cavity mirror 52 are a first end surface 61 and a second end surface 62, and a 45-degree oblique angle is formed between the first end surface 61 and the second end surface 62 and the large surface; the first end face 61 and the second end face 62 are used to reflect pump light into the bond plate bar gain medium to pump the first thulium doped section 21. The pump light is 785nm semiconductor laser, and is injected into the first end face 61 or the second end face 62 from the direction perpendicular to the large face, and is reflected to the bonding plate bar gain medium by the first end face 61 or the second end face 62 to pump the first thulium doped part 21, so that the pump light is conveniently injected into the bonding plate bar gain medium.

In one embodiment of the utility model, the 2.1 μm seed laser 1 is amplified by at least one pass in the holmium doped section 23. When the number of amplification passes is one, as shown in fig. 1 and 2, 2.1 μm seed laser light 1 is injected from the holmium doping portion 23 of the first side surface 7, travels in a Zigzag optical path inside the holmium doping portion 23 until being emitted from the holmium doping portion 23 of the second side surface 8.

As shown in FIG. 1, the intracavity pump low-heat Ho slab laser amplifier comprises a 2.1 mu m seed laser 1, a bonding plate slab gain medium 2, a crystal heat sink 3, a pump source 4 and a thulium laser resonant cavity 5. Wherein the 2.1 mu m seed laser 1 is output by an optical parametric laser, and the emission wavelength peak of the holmium doped laser medium can be precisely aligned through wavelength tuning. The material of the bonding plate bar gain medium matrix 2 is a YAG crystal, and includes a first thulium doped portion 21 and a second thulium doped portion 22, i.e., tm: YAG, with a doping concentration of 2%. The holmium doped part 23 is Ho, YAG, and the doping concentration is 0.5%. YAG 2-1, 2-2 and Ho YAG 2-3 are bonded into a whole by a growth bonding mode to form the bonding plate bar gain medium 2. The length, width and thickness of the gain medium 2 of the bonding plate bar are respectively 100mm,20mm and 2mm. The two end faces 61 and 62 of the gain medium 2 are beveled by 45 degrees, and the pump light 41 emitted by the pump source 4 is coupled to the first end face 61 and the second end face 62 after being shaped, and is coupled into the gain medium 2 of the key plate bar under the full internal return action of the first end face 61 and the second end face 62 and is fully absorbed by the Tm: YAG first thulium doped part 21 and second thulium doped part 22. The thulium laser resonant cavity 5 comprises two cavity mirrors 52, which are both plated with a film system highly reflecting thulium laser 51, namely, the reflectivity of the thulium laser resonant cavity is more than 99% for the wave band of 1.9-2.0 mu m. The thulium laser 51 travels in a Zigzag optical path inside the bonding plate bar gain medium 2, and realizes oscillation feedback of the thulium laser 51 under the action of the thulium laser resonant cavity 5. It should be noted that the thulium laser 51 fills the entire bond bar gain medium 2 and the first and second end faces 61, 62 as it travels in a Zigzag path within the bond bar gain medium 2, and that the propagation path of the thulium laser 51 is depicted in fig. 1 as a line segment for clarity purposes only, and does not represent the actual beam size. The thulium laser 51 has a wavelength of 2.02 μm and is sufficiently absorbed by Ho: YAG when passing through the holmium doped portion 23, thereby transferring laser energy from the thulium laser 51 to the Ho: YAG crystal, causing the holmium doped portion 23 to be in an active state.

Referring to fig. 2, the first side 7 and the second side 8 of the gain medium 2 of the bonding plate bar are polished surfaces in the holmium doped partial area, i.e. the first side holmium doped area 72 and the second side holmium doped area 82, and are coated with a film system for anti-reflection of 2.1 wave bands. After shaping, the 2.1 mu m seed laser 1 is injected into the holmium doped part 2-3 from the side surface and emitted from the side surface to realize the 2.1 mu m seed laser amplification output.

In one embodiment of the utility model, the 2.1 μm seed laser 1 is amplified in a number of passes in the holmium doped section 23 and is made to travel in a turn-back manner by the mirror 9. As shown in fig. 3 and 4, a schematic diagram of a 2.1 μm slab laser amplifier includes a 2.1 μm seed laser 1, a bonding plate slab gain medium 2, a crystal heat sink 3, a pump source 4, and a thulium laser resonator 5. Wherein a 2.1 μm seed laser is output by a holmium laser. The material of the bonding plate bar gain medium matrix 2 is YAG crystal, and comprises thulium doped parts 2-1 and 2-2, namely Tm is YAG, and the doping concentration is 2%. The holmium doped portion 23, i.e. Ho: YAG, has a doping concentration of 0.5% and a first undoped portion 24.Tm: YAG 2-1 and Ho: YAG 2-2 and the second undoped portion 25 are bonded as a whole by growth bonding to constitute the bonded slab gain medium 2. The length, width and thickness of the gain medium 2 of the bonding plate bar are respectively 100mm,20mm and 2mm. The first end surface 61 and the second end surface of the key plate bar gain medium 2 are cut with an oblique angle of 45 degrees with the large surface, the pump light 41 emitted by the pump source 4 is coupled to the end surfaces after being shaped, and is coupled into the key plate bar gain medium 2 under the full internal return action of the first end surface 61 and the second end surface 62 and is fully absorbed by the Tm: YAG 2-1. The thulium laser resonant cavity 5 comprises two cavity mirrors 52, which are both plated with a film system highly reflecting thulium laser 51, namely, the reflectivity of the thulium laser resonant cavity is more than 99% for the wave band of 1.9-2.0 mu m. The thulium laser 51 travels in a Zigzag optical path inside the bonding plate bar gain medium 2, and realizes oscillation feedback of the thulium laser 51 under the action of the thulium laser resonant cavity 5. It should be noted that the thulium laser 5-3 fills the entire bond bar gain medium 2 and the first and second end faces 61, 62 as it travels in a Zigzag path within the bond bar gain medium 2, and that the propagation path of the thulium laser 51 is depicted in fig. 3 as a line segment for clarity purposes only, and does not represent the actual beam size. The thulium laser 51 has a wavelength of 2.02 μm and is sufficiently absorbed by Ho: YAG when passing through the holmium doped portion 23, thereby transferring laser energy from the thulium laser 51 to the Ho: YAG crystal, causing the holmium doped portion 23 to be in an active state.

Referring to fig. 5, the first side 7 and the second side 8 of the gain medium 2 of the bonding plate bar are polished surfaces in holmium doped partial areas, namely, the first side holmium doped area 72 and the second side holmium doped area 82, form an included angle of 56 ° with the crystal large surface, and are coated with a film system for enhancing reflection of 2.1 wave bands. The 2.1 μm seed laser 1 is shaped, then is injected into the holmium doped part 23 from the first side holmium doped region 72, is emitted from the second side holmium doped region 82, is reflected by the reflecting mirror 9, and then passes through the holmium doped part 23 again to realize double-pass amplification, and the wave plate 10 is a 2.1 μm quarter wave plate, so that the 2.1 μm laser passes through the polarized state deflection 90 degrees twice, and the double-pass amplified 2.1 μm laser can be output from the polarizing plate 11 to realize the amplified output of the 2.1 μm seed laser. Referring to fig. 5,2.1 μm seed laser 1 is injected into the holmium doped portion 23 from the first side surface holmium doped region 72 and then travels in an Zigzag optical path inside the slab crystal, thereby canceling the thermal lens effect in the crystal thickness direction during the amplification process.

In addition, as shown in fig. 6, after being shaped, the 2.1 μm seed laser 1 is injected into the holmium doped part 23 from the first side surface 72 and is emitted from the second side surface 82, and after being reflected by the reflecting mirror 9 at a small angle, the seed laser passes through the holmium doped part 23 again, is emitted from the first side surface holmium doped region 72 and is reflected again by the reflecting mirror 9 into the holmium doped part 23, and so on, a multi-pass amplification is formed, the number of passes of the multi-pass amplification can be determined according to the light spot size and the inclination angles of the two reflecting mirrors 9, and the designed amplification passes of 2.1 μm laser is emitted from the edge of one of the reflecting mirrors 9, so that the output of the 2.1 μm laser is realized.

In describing embodiments of the present utility model, it should be noted that, unless explicitly stated and limited otherwise, the terms "coupled," "coupled," and "connected" should be construed broadly, and may be either a fixed connection, a removable connection, or an integral connection, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in the embodiments of the present utility model will be understood by those of ordinary skill in the art according to specific circumstances.

In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "manner," "particular modes," or "some modes," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or mode is included in at least one embodiment or mode of the embodiments of the present utility model. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or manner. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or ways. Furthermore, various embodiments or modes and features of various embodiments or modes described in this specification can be combined and combined by those skilled in the art without mutual conflict.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present utility model, and are not limiting; although the utility model has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present utility model.

Claims (10)

1. A 2.1 μm band holmium slab laser amplifier for amplifying 2.1 μm seed laser, comprising:

a thulium laser resonant cavity (5) for emitting thulium laser (51); the transmission direction of the thulium laser (51) is perpendicular to the transmission direction of the 2.1 μm seed laser;

the bonding plate bar gain medium (2) is arranged in the thulium laser resonant cavity (5); the laser diode comprises a first thulium doped part (21) and a holmium doped part (23), wherein the first thulium doped part (21) and the holmium doped part (23) are sequentially arranged along the transmission direction of thulium laser (51); the thulium laser (51) travels in a Zigzag optical path in the bonding plate bar gain medium (2), and forms feedback oscillation of the thulium laser (51) in the thulium laser resonant cavity (5);

and the pump source (4) is used for generating pump light and coupling the pump light after shaping with the bonding plate bar gain medium (2).

2. The 2.1 μm band holmium slab laser amplifier of claim 1, wherein the thulium laser resonator (5) has two mirrors (52); and the cavity mirrors (52) are all plated with high-reflection films for reflecting 1.9-2.0 mu m thulium laser.

3. The 2.1 μm band holmium slab laser amplifier of claim 1, wherein the bond slab gain medium (2) further comprises: the second thulium doped part (22), a first undoped part (24) and a second undoped part (25), wherein the first thulium doped part (21), the first undoped part (24), the holmium doped part (23), the second undoped part (25) and the second thulium doped part (22) are sequentially arranged.

4. The holmium slab laser amplifier of 2.1 μm band according to claim 1, characterized in that the side of the holmium doped part (23) parallel to the thulium laser transmission direction is a polished surface and is coated with an antireflection film to 2.1 μm laser; the side surface of the first thulium doped part (21) parallel to the thulium laser transmission direction is a texturing surface.

5. The 2.1 μm band holmium slab laser amplifier of claim 1, wherein the substrate of the bond slab gain medium (2) is one of YAG crystal, YLF crystal, YVO4 crystal, YAP crystal, YAG ceramic.

6. The holmium slab laser amplifier of claim 2, wherein the key slab gain medium (2) has a thickness of 1mm-10mm, a width of 5mm-50mm, and a length of 30mm-200mm.

7. The 2.1 μm band holmium slab laser amplifier of claim 6, wherein the side of the key slab gain medium (2) near the 2.1 μm seed laser (1) is a first side (7) and the plane opposite the first side (7) is a second side (8); the plane formed by the key plate strip gain medium (2) along the length direction and the width direction is a large surface;

an included angle of 30-60 degrees is formed between the first side surface (7) and the large surface and between the second side surface (8) and the large surface; the 2.1 mu m seed laser (1) is injected into the holmium doping part (23) from the first side surface (7), and advances in the holmium doping part (23) in a Zigzag optical path, and forms feedback oscillation of thulium laser in the thulium laser resonant cavity (5).

8. The 2.1 μm band holmium slab laser amplifier of claim 7, wherein the side of the key slab gain medium (2) near the cavity mirror (52) is a first end face (61) and a second end face (62), the first end face (61) and the second end face (62) forming a 45 ° bevel with the large face; the first end face (61) and the second end face (62) are used for reflecting the pump light into the bonding plate bar gain medium (2).

9. The holmium slab laser amplifier according to claim 1, wherein the number of amplification passes of the 2.1 μm seed laser (1) in the holmium doped section (23) is multiple, and the 2.1 μm seed laser is folded back by a mirror (9).

10. The 2.1 μm band holmium slab laser amplifier of claim 7, wherein the bond slab gain medium (2) is welded with the large face as a contact face to a crystalline heat sink.