High efficiency all-solid-state mid-infrared 2 and 4 mu m dual-wavelength continuous wave laser

Abstract

The application relates to a linear-method-based semiconductor laser, in particular to a high-efficiency all-solid-state mid-infrared 2-micron and 4-micron dual-wavelength continuous laser, which is used for solving the problem that although 2-micron waveband solid continuous laser output is obtained by utilizing a 1.15-micron laser to pump a holmium-doped crystal, and 4-micron waveband solid continuous laser output is obtained by utilizing a 3-micron waveband continuous laser to pump a zinc selenide crystal doped with iron, the laser can only obtain single-wavelength output of the 2-micron or 4-micron waveband. The high-efficiency all-solid-state mid-infrared 2-micron and 4-micron dual-wavelength continuous laser comprises a resonant cavity, a cryostat, a pumping laser, a collimating and focusing system and a laser gain medium; the application firstly proposes that high-power 1-micron waveband laser is utilized to pump a holmium-iron co-doped crystal to realize simultaneous output of 2-micron and 4-micron laser, and the 4-micron laser efficiency can be greatly improved while the 2-micron laser output is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to linear method-based semiconductor laser, and in particular to high-efficiency all-solid-state mid-infrared 2μm and 4μm dual-wavelength continuous laser. BACKGROUND

[0002] The mid-infrared 2-4μm waveband continuous laser light source has strong transmission ability in the atmosphere, and corresponds to the radiation spectrum of substances and the characteristic spectrum of some gas molecules, and has a wide application in the field of atmospheric monitoring / detection in the civil field, and in recent years, it has been favored by researchers, therefore, developing high-efficiency mid-infrared 2-4μm waveband all-solid-state continuous laser has important scientific significance and application value.

[0003] At present, the generation methods of solid-state continuous-wave mid-infrared 2-4 μm band laser mainly include linear method based on population inversion and nonlinear method based on nonlinear effect, wherein the nonlinear method includes optical parametric oscillation, optical parametric amplification, sum frequency and difference frequency, etc., and the linear method includes semiconductor quantum cascade laser and infrared-pumped transition metal iron ion doped crystal material, etc. The nonlinear method can generate 1.5 μm and 4 μm idler and signal light outputs, but in the continuous operation system, the laser output power stability is poor, and the efficiency is low. In the linear method, the semiconductor laser also has the problems of poor beam quality, limited power, etc., and can only realize single wavelength output. While using thulium-doped fiber laser to pump holmium-doped crystal can obtain all-solid-state high-power 2 μm laser output, and using infrared-pumped transition metal iron ion doped crystal material to generate 4 μm band continuous laser output, such technology has the advantages of good beam quality, high efficiency, wavelength tunable, good power stability, scalable amplification, compact structure and easy integration, etc. At present, there are many literatures reporting that 2 μm band solid-state continuous-wave laser output is obtained by pumping holmium-doped crystal with 1.15 μm laser, and 4 μm band solid-state continuous-wave laser output is obtained by pumping iron-doped zinc selenide crystal with 3 μm band continuous-wave laser. In 2013, Wang et al. reported that 1.4 W of 2.07 μm laser output was obtained by pumping Ho:LuLiF4 crystal with 1.15 μm laser, and the slope efficiency was 29% (2013, Vol. 21, Optics Express, “Efficient Ho:LuLiF4 laser diode-pumped at 1.15 μm”). In 2018, Pushkin et al. pumped iron-doped zinc selenide crystal with a 2.8 μm fiber laser, and obtained 2.1 W of 4 μm band continuous-wave laser output at low temperature of 77 K, and the optical-to-optical conversion efficiency was as high as 32% (2018, Vol. 43, Optics Letters, “Compact, highly efficient, 2.1-W continuous-wave mid-infrared Fe:ZnSe coherent source, pumped by an Er:ZBLAN fiber laser”). However, such laser can only obtain 2 μm or 4 μm band single wavelength output. SUMMARY

[0004] The present application aims at solving the problem that although 2-micron-band solid-state continuous laser output is obtained by using a 1.15-micron laser to pump a holmium-doped crystal, and 4-micron-band solid-state continuous laser output is obtained by using a 3-micron-band continuous laser to pump a zinc selenide crystal doped with iron, such lasers can only obtain single-wavelength output in the 2-micron or 4-micron band, and provides a high-efficiency all-solid-state mid-infrared 2-micron and 4-micron dual-wavelength continuous laser.

[0005] In order to solve the problem existing in the prior art, the present application provides the following technical solutions:

[0006] A high-efficiency all-solid-state mid-infrared 2-micron and 4-micron dual-wavelength continuous laser, characterized in that it comprises a resonant cavity, a cryostat, and a pump laser, a collimating and focusing system, and a laser gain medium arranged in sequence along an optical path.

[0007] The collimating and focusing system comprises two plano-convex lenses.

[0008] The laser gain medium is loaded in the cryostat,

[0009] The cryostat is used for controlling the temperature of the laser gain medium, and is located in the resonant cavity, and two light-transmitting windows are arranged on the cryostat at positions coinciding with the optical path.

[0010] The resonant cavity is one of a linear resonant cavity, a three-mirror V-shaped resonant cavity, and a four-mirror X-shaped resonant cavity.

[0011] Further, the pump laser is a laser with a wavelength in the range of 1100-1160 nm.

[0012] Further, the laser gain medium is a holmium-iron co-doped crystal, the holmium ion doping concentration is 0.5-5 mol%, the iron ion doping concentration is 0.01-1 mol%, and the base material is one of calcium fluoride, magnesium fluoride, zinc selenide, zinc sulfide, zinc telluride, and cadmium selenide.

[0013] Further, the cryostat adopts liquid nitrogen refrigeration, the refrigeration temperature of the cryostat is 20-90 K, the material of the light-transmitting window is one of calcium fluoride, magnesium fluoride, and zinc selenide, a dielectric film A is coated on the light-transmitting window, and the transmittance of the dielectric film A for 1100-1160 nm, the 2-micron band, and the 4-micron band is greater than or equal to 95%.

[0014] Further, the resonant cavity is a linear resonant cavity, the resonant cavity comprises a plano-concave total reflection cavity mirror and a flat-flat output cavity mirror arranged in sequence along an optical path, and the laser gain medium is located between the plano-concave total reflection cavity mirror and the flat-flat output cavity mirror; a laser incidence surface of the plano-concave total reflection cavity mirror is a plane, and a laser emission surface is a concave surface; the plano-concave total reflection cavity mirror is coated with a dielectric film B, the dielectric film B has a transmittance of ≥95% for 1100-1160 nm, and a reflectivity of ≥99% for 2 μm and 4 μm bands; and the flat-flat output cavity mirror is coated with a dielectric film C, the dielectric film C has a reflectivity of ≥95% for 1100-1160 nm, a reflectivity of 4-90% for 2 μm band, and a reflectivity of 10-90% for 4 μm band.

[0015] Further, the resonant cavity is a three-mirror V-type resonant cavity, the resonant cavity comprises a plano-concave total reflection cavity mirror, a plano-concave total reflection mirror and a flat-flat output cavity mirror arranged in sequence along an optical path, and the laser gain medium is located between the plano-concave total reflection cavity mirror and the plano-concave total reflection mirror; a laser incidence surface of the plano-concave total reflection cavity mirror is a plane, and a laser emission surface is a concave surface; a laser incidence surface of the plano-concave total reflection mirror is a concave surface; the plano-concave total reflection cavity mirror and the plano-concave total reflection mirror are coated with a dielectric film B, the dielectric film B has a transmittance of ≥95% for 1100-1160 nm, and a reflectivity of ≥99% for 2 μm and 4 μm bands; and the flat-flat output cavity mirror is coated with a dielectric film C, the dielectric film C has a reflectivity of ≥95% for 1100-1160 nm, a reflectivity of 4-90% for 2 μm band, and a reflectivity of 10-90% for 4 μm band.

[0016] Further, the resonant cavity is a four-mirror X-type resonant cavity, the resonant cavity comprises a plano-concave total reflection cavity mirror, a plano-concave total reflection mirror, a flat-flat total reflection mirror and a flat-flat output cavity mirror, and the laser gain medium is located between the plano-concave total reflection cavity mirror and the plano-concave total reflection mirror; a laser incidence surface of the plano-concave total reflection cavity mirror is a plane, and a laser emission surface is a concave surface; a laser incidence surface of the plano-concave total reflection mirror is a concave surface; the flat-flat total reflection mirror is arranged on a reflected light path of the plano-concave total reflection cavity mirror, and the flat-flat output cavity mirror is arranged on a reflected light path of the plano-concave total reflection cavity mirror; the plano-concave total reflection cavity mirror, the plano-concave total reflection mirror and the flat-flat total reflection mirror are coated with a dielectric film B, the dielectric film B has a transmittance of ≥95% for 1100-1160 nm, and a reflectivity of ≥99% for 2 μm and 4 μm bands; and the flat-flat output cavity mirror is coated with a dielectric film C, the dielectric film C has a reflectivity of ≥95% for 1100-1160 nm, a reflectivity of 4-90% for 2 μm band, and a reflectivity of 10-90% for 4 μm band.

[0017] Further, the resonant cavity is a linear resonant cavity, the resonant cavity comprises a double dichroic mirror, a flat-flat output cavity mirror and a flat-concave total reflection cavity mirror arranged in sequence along an optical path, and the laser gain medium is located between the flat-concave total reflection cavity mirror and the flat-flat output cavity mirror; an included angle between the double dichroic mirror and the optical path is 45°, a laser incidence surface of the flat-concave total reflection cavity mirror is a concave surface, a laser emission surface is a flat surface, the flat-concave total reflection cavity mirror is coated with a dielectric film B, the double dichroic mirror and the dielectric film B have a transmittance of ≥95% for 1100-1160 nm, and a reflectivity of ≥99% for 2 μm and 4 μm wave bands; the flat-flat output cavity mirror is coated with a dielectric film C, the dielectric film C has a reflectivity of ≥95% for 1100-1160 nm, a reflectivity of 4-90% for the 2 μm wave band, and a reflectivity of 10-90% for the 4 μm wave band.

[0018] Compared with the prior art, the high-efficiency full-solid-state mid-infrared 2 μm and 4 μm dual-wavelength continuous laser has the following beneficial effects:

[0019] (1) The high-efficiency full-solid-state mid-infrared 2 μm and 4 μm dual-wavelength continuous laser comprises a resonant cavity, a cryostat, a pump laser, a collimating and focusing system and a laser gain medium; the high-efficiency full-solid-state mid-infrared 2 μm and 4 μm dual-wavelength continuous laser is first proposed to use a high-power 1 μm wave band laser to pump a holmium-iron co-doped crystal to realize simultaneous output of 2 μm and 4 μm two wavelengths, and the 4 μm laser efficiency can be greatly improved while the 2 μm laser output is obtained.

[0020] (2) The high-efficiency full-solid-state mid-infrared 2 μm and 4 μm dual-wavelength continuous laser adopts a linear method to avoid a complex process of nonlinear effects, and a 1 μm wave band high-power and high-beam-quality fiber laser can be used as a pump source, so that the entire laser has the advantages of simple structure, small size, good beam quality, stable and reliable performance, high-power output and the like. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 FIG. 1 is a structural schematic diagram of the high-efficiency full-solid-state mid-infrared 2 μm and 4 μm dual-wavelength continuous laser embodiment one of the present application;

[0022] Figure 2 FIG. 2 is a structural schematic diagram of the high-efficiency full-solid-state mid-infrared 2 μm and 4 μm dual-wavelength continuous laser embodiment two of the present application;

[0023] Figure 3 FIG. 3 is a structural schematic diagram of the high-efficiency full-solid-state mid-infrared 2 μm and 4 μm dual-wavelength continuous laser embodiment three of the present application;

[0024] Figure 4 FIG. 4 is a structural schematic diagram of the high-efficiency full-solid-state mid-infrared 2 μm and 4 μm dual-wavelength continuous laser embodiment four of the present application;

[0025] Figure 5 FIG. 5 is an energy level diagram of holmium ions and iron ions in the laser gain medium of the high-efficiency full-solid-state mid-infrared 2 μm and 4 μm dual-wavelength continuous laser embodiment one of the present application.

[0026] The reference signs are explained as follows: 1-pump laser; 2-collimating focusing system; 3-flat concave total reflection mirror; 4-light transmission window; 5-laser gain medium; 6-cryostat; 7-flat-flat output mirror; 8-flat-concave total reflection mirror; 9-flat-flat total reflection mirror; 10-double color mirror; 11-holmium ion 5 I8 energy level; 12-holmium ion 5 I7 energy level; 13-holmium ion 5 I6 energy level; 14-1150nm ground state absorption process; 15-3μm stimulated radiation; 16-2μm stimulated radiation; 17-energy transfer process; 18-iron ion 5 T2|3> energy level; 19-iron ion 3μm ground state absorption process; 20-iron ion 5 E|g> energy level; 21-non-radiative relaxation process; 22-iron ion 5 T2|2> energy level; 23-4μm stimulated radiation; 24-iron ion 5 E|1> energy level. DETAILED DESCRIPTION

[0027] The application will be further described below in conjunction with the drawings and exemplary embodiments.

[0028] Embodiment one

[0029] Reference Figure 1 A high-efficiency all-solid-state mid-infrared 2μm and 4μm dual-wavelength continuous laser includes a resonant cavity, a cryostat 6, and a pump laser 1, a collimating focusing system 2, and a laser gain medium 5 arranged in sequence along an optical path.

[0030] The pump laser 1 is a laser with a wavelength of 1150nm.

[0031] The collimating focusing system 2 includes two flat-convex lenses with a focal length of 50mm.

[0032] The laser gain medium 5 is a holmium-iron co-doped zinc selenide crystal (Ho / Fe:ZnSe), wherein the holmium ion doping concentration is 1.5mol%, the iron ion doping concentration is 0.1mol%, the laser gain medium 5 is loaded on a red copper heat sink and installed in the cryostat 6.

[0033] The cryostat 6 is used to control the temperature of the laser gain medium 5 through liquid nitrogen refrigeration, and the refrigeration of the cryostat 6 is 78K; the cryostat 6 is located in the resonant cavity, and two light transmission windows 4 are arranged on the cryostat 6 at a position coinciding with the optical path, the light transmission windows 4 are coated with a dielectric film A, and the dielectric film A has a transmittance ≥95% for a wavelength of 1100-1160nm, a 2μm wavelength band and a 4μm wavelength band.

[0034] The resonant cavity is a linear resonant cavity, and the resonant cavity comprises a plano-concave total reflection cavity mirror 3 and a plano-plano output cavity mirror 7 arranged in sequence along an optical path; the laser gain medium 5 is located between the plano-concave total reflection cavity mirror 3 and the plano-plano output cavity mirror 7; the laser incidence surface of the plano-concave total reflection cavity mirror 3 is a plane, and the laser emission surface is a concave surface; the plano-concave total reflection cavity mirror 3 is coated with a dielectric film B, the transmittance of the dielectric film B for 1100-1160 nm is greater than or equal to 95%, and the reflectivity for 2 μm and 4 μm bands is greater than or equal to 99%; the plano-plano output cavity mirror 7 is coated with a dielectric film C, the reflectivity of the dielectric film C for 1100-1160 nm is greater than or equal to 95%, the reflectivity for the 2 μm band is 4-90%, and the reflectivity for the 4 μm band is 10-90%.

[0035] The temperature control of the cryostat 6 is set to 78 K, and after the temperature of the laser gain medium 5 reaches the set temperature, the pump laser 1 is turned on. The 1150 nm pump light output by the pump laser 1 enters the laser gain medium 5 in the resonant cavity after passing through the collimating and focusing system 2.

[0036] The 2 μm and 4 μm dual-wavelength laser generation process is as shown in Figure 5 The holmium ions in the holmium ion 5 I8 energy level 11 are pumped by 1150 nm ground state absorption pump light process 14 to jump to the upper holmium ion 5 I6 energy level 13, the holmium ions in the energy level jump downward to the holmium ion 5 I7 energy level 12, and generate 3 μm stimulated radiation 15. The iron ions absorb the 3 μm stimulated radiation photon energy through the energy transfer process 17, and jump from the iron ion 5 E|g> energy level 20 to the iron ion 5 T2|3> energy level 18, and quickly jump to the iron ion 5 T2|2> energy level 22 through a non-radiative relaxation process 21. The iron ions in the iron ion 5 T2|2> energy level 22 jump downward to the iron ion 5 E|1> energy level 24, and generate 4 μm stimulated radiation 23. The holmium ions in the holmium ion 5 I7 energy level 12 further jump downward to the holmium ion 5 I8 energy level 11, and generate 2 μm stimulated radiation 16. This process of generating 2 μm stimulated radiation 16 has two effects: one is to consume the holmium ions 5 I7 energy level 12, which is beneficial to obtain the holmium ions 5 I6 energy level 13→ holmium ion 5 I7 energy level 12 jump particle inversion, and the other is to generate 2 μm stimulated radiation 16, realizing 2 μm wavelength laser output.

[0037] When the pump power exceeds the oscillation threshold, the flat-concave total reflection mirror 3 and the flat-flat output mirror 7 are adjusted to realize high-efficiency oscillation of the 2 μm and 4 μm dual-wavelength lasers in the resonant cavity. The laser in the resonant cavity is outputted through the flat-flat output mirror 7. The 2 μm and 4 μm laser output power increases with the increase of the pump power.

[0038] Embodiment Two

[0039] With reference to Figure 2 In this embodiment, the pump laser 1 is a laser with a wavelength of 1100 nm. The laser gain medium 5 is a holmium-iron co-doped zinc selenide crystal (Ho / Fe: ZnSe), in which the holmium ion doping concentration is 0.5 mol% and the iron ion doping concentration is 0.01 mol%. The refrigeration of the cryostat 6 is 90 K.

[0040] The flat-flat output mirror 7 and the flat-concave total reflection mirror 3 in Embodiment One are exchanged in position. The laser incidence surface of the flat-concave total reflection mirror 3 is a concave surface, and the laser emission surface is a flat surface. A dichroic mirror 10 is placed between the flat-flat output mirror 7 and the collimating and focusing system 2. The included angle between the dichroic mirror 10 and the optical path is 45°. The transmittance of the dichroic mirror 10 to 1100-1160 nm is ≥95%, and the reflectivity of the dichroic mirror 10 to the 2 μm and 4 μm bands is ≥99%. In this way, the 2 μm and 4 μm dual-wavelength laser output can also be obtained by using the backward pumping mode.

[0041] The rest of the settings in this embodiment are consistent with those in Embodiment One.

[0042] Embodiment Three

[0043] With reference to Figure 3 In this embodiment, the pump laser 1 is a laser with a wavelength of 1160 nm. The laser gain medium 5 is a holmium-iron co-doped zinc selenide crystal (Ho / Fe: ZnSe), in which the holmium ion doping concentration is 3 mol% and the iron ion doping concentration is 0.5 mol%. The refrigeration of the cryostat 6 is 50 K.

[0044] The resonant cavity is a three-mirror V-type resonant cavity, which comprises, in sequence along the optical path, the flat-concave total reflection mirror 3, the flat-concave total reflection mirror 8, and the flat-flat output mirror 7. The laser gain medium 5 is located between the flat-concave total reflection mirror 3 and the flat-concave total reflection mirror 8. The laser incidence surface of the flat-concave total reflection mirror 3 is a flat surface, and the laser emission surface is a concave surface. The laser incidence surface of the flat-concave total reflection mirror 8 is a concave surface. The flat-concave total reflection mirror 3 and the flat-concave total reflection mirror 8 are coated with the medium film B. The flat-flat output mirror 7 is coated with the medium film C.

[0045] The rest of the settings in this embodiment are consistent with those in Embodiment One.

[0046] Embodiment Four

[0047] With reference toFigure 4 The pump laser 1 in the embodiment is a laser with a wavelength of 1150 nm. The laser gain medium 5 is a holmium-iron co-doped zinc selenide crystal (Ho / Fe:ZnSe) with a holmium ion doping concentration of 5 mol% and an iron ion doping concentration of 1 mol%. The cryostat 6 has a refrigeration temperature of 20 K.

[0048] The resonant cavity is a four-mirror X-type resonant cavity, which includes a plano-concave total reflection cavity mirror 3, a plano-concave total reflection mirror 8, a plano-plano total reflection mirror 9, and a plano-plano output cavity mirror 7. The laser gain medium 5 is located between the plano-concave total reflection cavity mirror 3 and the plano-concave total reflection mirror 8. The plano-plano total reflection mirror 9 is arranged on the reflection light path of the plano-concave total reflection mirror 8, and the plano-plano output cavity mirror 7 is arranged on the reflection light path of the plano-concave total reflection cavity mirror 3. The embodiment adds the plano-plano total reflection mirror 9 to the embodiment three, and the plano-plano total reflection mirror 9 is coated with the dielectric film B.

[0049] The rest of the settings in the embodiment are consistent with those in the embodiment three.

[0050] In other embodiments, the plano-plano total reflection mirror 9 in the embodiment can be replaced by a grating or a prism can be added in front of the plano-plano total reflection mirror 9, so that the laser wavelength can be tuned and the laser linewidth can be narrowed.

[0051] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it. For ordinary skilled in the art, the specific technical solutions described in the above embodiments can be modified, or some technical features can be replaced by equivalent ones, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions protected by the present application.

Claims

1. A high efficiency all solid state mid-infrared 2 pm and 4 pm dual-wavelength continuous wave laser, characterized in that: The resonant cavity, a cryostat (6), and a pump laser (1), a collimating and focusing system (2), and a laser gain medium (5) arranged in sequence along an optical path; The pump laser (1) is a laser with a wavelength in the range of 1100-1160 nm; The collimating and focusing system (2) comprises two plano-convex lenses; The laser gain medium (5) is a holmium-iron co-doped crystal, the holmium ion doping concentration is 0.5-5 mol%, the iron ion doping concentration is 0.01-1 mol%, the base material is one of calcium fluoride, magnesium fluoride, zinc selenide, zinc sulfide, zinc telluride and cadmium selenide, and the laser gain medium (5) is loaded in the cryostat (6); The cryostat (6) adopts liquid nitrogen refrigeration, the refrigeration temperature of the cryostat (6) is 20-90 K, and the cryostat (6) is used for controlling the temperature of the laser gain medium (5); the cryostat (6) is located in the resonant cavity, and two light transmission windows (4) are arranged on the cryostat (6) at positions coinciding with the optical path. The light transmission window (4) is made of one of calcium fluoride, magnesium fluoride and zinc selenide, and a dielectric film A is coated on the light transmission window (4); the dielectric film A has a transmittance of ≥95% for a 1100-1160 nm, 2 μm wave band and a 4 μm wave band. The resonant cavity is one of a linear resonant cavity, a three-mirror V-shaped resonant cavity and a four-mirror X-shaped resonant cavity.

2. The high efficiency all solid state mid-infrared 2 pm and 4 pm dual-wavelength continuous wave laser of claim 1, wherein: The resonant cavity is a linear resonant cavity, and the resonant cavity comprises a plano-concave total reflection cavity mirror (3) and a flat-flat output cavity mirror (7) arranged in sequence along an optical path, and the laser gain medium (5) is located between the plano-concave total reflection cavity mirror (3) and the flat-flat output cavity mirror (7); the laser incidence surface of the plano-concave total reflection cavity mirror (3) is a plane, and the laser emission surface is a concave surface; a dielectric film B is coated on the plano-concave total reflection cavity mirror (3); the dielectric film B has a transmittance of ≥95% for a 1100-1160 nm wave band, and a reflectivity of ≥99% for a 2 μm wave band and a 4 μm wave band; a dielectric film C is coated on the flat-flat output cavity mirror (7); the dielectric film C has a reflectivity of ≥95% for a 1100-1160 nm wave band, a reflectivity of 4-90% for a 2 μm wave band, and a reflectivity of 10-90% for a 4 μm wave band.

3. The high efficiency all solid state mid-infrared 2 pm and 4 pm dual-wavelength continuous wave laser of claim 1, wherein: The resonant cavity is a three-mirror V-shaped resonant cavity, and the resonant cavity comprises a plano-concave total reflection cavity mirror (3), a plano-concave total reflection mirror (8) and a flat-flat output cavity mirror (7) arranged in sequence along an optical path, and the laser gain medium (5) is located between the plano-concave total reflection cavity mirror (3) and the plano-concave total reflection mirror (8); the laser incidence surface of the plano-concave total reflection cavity mirror (3) is a plane, and the laser emission surface is a concave surface; the laser incidence surface of the plano-concave total reflection mirror (8) is a concave surface; a dielectric film B is coated on the plano-concave total reflection cavity mirror (3) and the plano-concave total reflection mirror (8); the dielectric film B has a transmittance of ≥95% for a 1100-1160 nm wave band, and a reflectivity of ≥99% for a 2 μm wave band and a 4 μm wave band; a dielectric film C is coated on the flat-flat output cavity mirror (7); the dielectric film C has a reflectivity of ≥95% for a 1100-1160 nm wave band, a reflectivity of 4-90% for a 2 μm wave band, and a reflectivity of 10-90% for a 4 μm wave band.

4. The high efficiency all solid state mid-infrared 2 pm and 4 pm dual-wavelength continuous wave laser of claim 1, wherein: The resonant cavity is a four-mirror X-shaped resonant cavity, and the resonant cavity comprises a plano-concave all-reflector mirror (3), a plano-concave all-reflector mirror (8), a plano-plano all-reflector mirror (9) and a plano-plano output cavity mirror (7), the laser gain medium (5) is located between the plano-concave all-reflector mirror (3) and the plano-concave all-reflector mirror (8); the laser incidence surface of the plano-concave all-reflector mirror (3) is a plane, and the laser emission surface is a concave surface, the laser incidence surface of the plano-concave all-reflector mirror (8) is a concave surface; the plano-plano all-reflector mirror (9) is arranged on the reflected light path of the plano-concave all-reflector mirror (8), and the plano-plano output cavity mirror (7) is arranged on the reflected light path of the plano-concave all-reflector mirror (3); the plano-concave all-reflector mirror (3), the plano-concave all-reflector mirror (8) and the plano-plano all-reflector mirror (9) are coated with a dielectric film B, the dielectric film B has a transmittance of ≥95% for 1100-1160 nm, and a reflectivity of ≥99% for 2 μm and 4 μm wave bands; the plano-plano output cavity mirror (7) is coated with a dielectric film C, the dielectric film C has a reflectivity of ≥95% for 1100-1160 nm, a reflectivity of 4-90% for 2 μm wave band, and a reflectivity of 10-90% for 4 μm wave band.

5. The high efficiency all solid state mid-infrared 2 pm and 4 pm dual-wavelength continuous wave laser of claim 1, wherein: The resonant cavity is a linear resonant cavity, and the resonant cavity comprises a bichromatic mirror (10), a plano-plano output cavity mirror (7) and a plano-concave all-reflector mirror (3) arranged in sequence along an optical path, the laser gain medium (5) is located between the plano-concave all-reflector mirror (3) and the plano-plano output cavity mirror (7); the included angle between the bichromatic mirror (10) and the optical path is 45°, the laser incidence surface of the plano-concave all-reflector mirror (3) is a concave surface, and the laser emission surface is a plane, the plano-concave all-reflector mirror (3) is coated with a dielectric film B, the bichromatic mirror (10) and the dielectric film B have a transmittance of ≥95% for 1100-1160 nm, and a reflectivity of ≥99% for 2 μm and 4 μm wave bands; the plano-plano output cavity mirror (7) is coated with a dielectric film C, the dielectric film C has a reflectivity of ≥95% for 1100-1160 nm, a reflectivity of 4-90% for 2 μm wave band, and a reflectivity of 10-90% for 4 μm wave band.

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