Intermediate infrared laser material and intermediate infrared laser generating device

Abstract

The invention discloses a mid-infrared laser material and a mid-infrared laser generating device. The mid-infrared laser material adopts AELn2S4 as a matrix material and adopts rare earth ions as active ions; wherein AE is Mg, Ca, Sr or Ba; and Ln is La, Sc, Y or Lu. The intermediate infrared laser material provided by the invention takes the rare earth sulfide with a cubic structure as a matrix material, the physical and chemical properties are stable, the symmetry of a crystal structure is high, the intermediate infrared laser material contains stronger AE-S and Ln-S bonds, so that the intermediate infrared laser material has very good mechanical properties, and the problem of crystal cleavage is avoided; ln ion lattice sites can be doped with same-family rare earth activated ions with the same valence states and similar ion radiuses, and the problem that precipitation phases are formed due to different valence states is solved. The built mid-infrared laser generating device has the advantages of being compact in structure, high in conversion efficiency and good in stability.

Description

Technical Field

[0001] The invention belongs to the technical field of laser gain medium materials, and in particular relates to a mid-infrared laser material and a mid-infrared laser generating device. Background Art

[0002] Mid-infrared lasers with a wavelength of 3-5 μm are widely used in infrared spectroscopy, infrared remote sensing, infrared countermeasures, infrared medical treatment, atmospheric monitoring, toxic gas detection and other fields. Practical applications require mid-infrared lasers to be fully solid-state, miniaturized, and highly stable. -1 ), multi-phonon fluorescence quenching makes it difficult for the output wavelength of oxide solid-state lasers to exceed 3μm. Usually, nonlinear optical frequency conversion technology is required to output 3-5μm solid-state lasers; however, this solution has high requirements for pump sources, complex structures, and relatively poor stability, making it difficult to promote and apply.

[0003] Dy 3+ , Pr 3+ 、Ho 3+ , Er 3+ Rare earth ions such as KPb can provide 3-5μm mid-infrared light emission spectra; domestic and foreign researchers have tried to incorporate such rare earth ions into low-phonon energy halide and sulfide matrices in order to obtain direct pumping and transport of mid-infrared lasers. The phonon energy of the fluoride matrix is ​​still relatively high and can only be used for laser output around 3μm; KPb 2 Cl 5 、LaCl 3 Such matrices are prone to deliquesce and cannot be used as practical laser matrix materials.

[0004] The University of California, USA and the Institute of General Physics of Russia used 1.32μm@Nd:YAG laser to pump Dy 3+ :CaGa 2 S 4 and Dy 3+ :PbGa 2 S 4 Crystals achieved laser output of 4.31-4.38μm and 4.3-4.7μm, respectively, verifying the feasibility of rare earth ion doped sulfide matrix crystals to output 3.0-5.0μm mid-infrared lasers. 2 S 4 (M=Ca,Pb) crystals are very easy to cleave along the

[001] crystal plane; moreover, due to the non-equivalent Dy 3+ Ion doping causes charge imbalance, and intrinsic defect charge compensation leads to the formation of clusters and high-melting-point rare earth sulfide precipitation phases, which affects Dy 3+ Ion doping concentration and uniformity. Therefore, it is impossible to obtain high-quality Dy3+ :MGa 2 S 4 Crystals hinder its widespread application.

[0005] Chinese patent [CN 109713560 A] discloses a mid-infrared iron-erbium double-doped laser crystal for 3.0-5.0μm all-solid-state lasers, using double-doped iron-erbium ions as activation ions, fluoride, chloride, bromide and PbGa 2 S 4 Crystal is used as laser matrix material. 3+ ions) co-doped with sensitized divalent iron ions (Fe 2+ ions) to achieve LD pumping of the crystal. However, the laser matrix used still has shortcomings. The phonon energy of fluoride is still high, making it difficult to achieve 3-5μm solid-state laser output; chloride and bromide substances are soft and easy to deliquesce, and cannot be used as practical laser matrix materials.

[0006] Chinese patent [CN 109713561 A] discloses a cobalt-erbium doped laser crystal for 2.6-4.0μm mid-infrared all-solid-state lasers, using cobalt-erbium ions as active ions, fluoride, chloride, bromide and PbGa 2 S 4 Crystal is used as laser matrix material. 3+ ions) co-doped with sensitized divalent iron ions (Co 2+ ions) to achieve LD pumping of the crystal. However, the laser matrix used still has shortcomings. The phonon energy of fluoride is still relatively high, making it difficult to achieve solid-state laser output above 3μm; chloride and bromide substances are soft and easy to deliquesce, and cannot be used as practical laser matrix materials.

[0007] In summary, using the existing low phonon energy MGa 2 S 4 (M=Ca,Pb),KPb 2 Cl 5 、LaCl 3 Such crystals cannot be used in practice as 3.0-5.0μm mid-infrared laser matrices. Summary of the invention

[0008] Aiming at the shortcomings of the existing 3-5μm mid-infrared laser materials, the mid-infrared laser material proposed in the present invention adopts AELn 2 S 4As the matrix material, rare earth ions are used as activation ions; wherein: AE is Mg, Ca, Sr or Ba; Ln is La, Sc, Y, or Lu; the obtained material has low phonon energy, stable physicochemical properties, high symmetry, is easy to prepare large-size laser components, and can be directly pumped out by LD pumping.

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] The first object of the present invention is to provide a mid-infrared laser material, wherein the mid-infrared laser material adopts AELn 2 S 4 As the matrix material, rare earth ions are used as activating ions; wherein: AE is Mg, Ca, Sr or Ba; Ln is La, Sc, Y or Lu. Preferably, the rare earth ion is Pr 3+ , Er 3+ 、Ho 3+ or Dy 3+ Further preferably, the mid-infrared laser material is Pr 3+ :MgLn 2 S 4 .

[0011] The second object of the present invention is to provide a mid-infrared laser generating device, which includes a laser pump source and a resonant cavity arranged along the laser output optical path of the laser pump source; the resonant cavity includes an input mirror, a laser crystal and an output mirror arranged along the optical path; the laser crystal is the mid-infrared laser material described in the first object above. Preferably, the laser pump source adopts LD pumping with a wavelength of 1.32-1.71μm. Further preferably, the laser pump source adopts LD pumping with wavelengths of 1.32μm, 1.55μm, 1.60μm, and 1.71μm.

[0012] The present invention has the following beneficial effects:

[0013] The mid-infrared laser material provided by the present invention is a rare earth sulfide AELn having a cubic structure. 2 S 4 As a matrix material, the crystal has stable physical and chemical properties and a highly symmetrical crystal structure. The strong AE-S and Ln-S bonds it contains determine that it has excellent mechanical properties and will not have crystal cleavage problems. The Ln ion site can be doped with the same family of rare earth activating ions with the same valence state and similar ionic radius, and there will be no problem of precipitation phase formation due to different valence states.

[0014] The present invention uses rare earth ions (Pr 3+ , Er 3+ 、Ho 3+ or Dy 3+) as the activation ion, LD pumping can be used to provide 3.5-5.5μm mid-infrared spectrum without co-doping sensitizing ions. The constructed mid-infrared laser generator has the characteristics of compact structure, high conversion efficiency and good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Pr 3+ :MgLa 2 S 4 Schematic diagram of ionic energy levels in crystalline materials;

[0016] Figure 2 MgLa 2 S 4 Schematic diagram of crystal structure;

[0017] Figure 3 Pr 3+ :MgLa 2 S 4 The transmittance of the crystal.

[0018] Figure 4 Pr 3+ :MgLa 2 S 4 Mid-infrared emission spectrum of the crystal.

[0019] Figure 5 This is a schematic diagram of the structure of the mid-infrared laser generating device.

[0020] Reference numerals: 1 - laser pump source, 2 - input mirror, 3 - laser crystal, 4 - output mirror. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0022] In addition, unless otherwise specified, the preparation processes in the following embodiments are all conventional means in the prior art in the field, and therefore, they are not described in detail; the raw materials used are all commercially available products.

[0023] Example 1

[0024] The mid-infrared laser material provided in this embodiment is Pr 3+ :MgLa 2 S 4 MgLa 2 S 4 As the matrix material, Pr 3+ As an active ion. The preparation method of the material is as follows:

[0025] La2 S 3 and MgS were weighed in a molar ratio of 1:1, and 1 wt% Pr 2 S 3 and 0.5wt% S. After the above raw materials are fully ground and mixed in a glove box, they are placed in a pyrolytic boron nitride crucible and sealed in a quartz crucible. The sealed quartz crucible is placed in a high-temperature and high-pressure furnace, heated to 1250°C, and a pressure of 30atm is applied. The temperature is kept constant for 15 days, and Pr is obtained after cooling down. 3+ :MgLa 2 S 4 Crystalline material.

[0026] Pr 3+ :MgLa 2 S 4 Pr in crystal materials 3+ Provide mid-infrared spectrum, ion energy level diagram as follows Figure 1 As shown. 2 S 4 As the matrix material, the space group structure is Fd-3m(227), Mg 2+ With S 2- Formation of tetrahedral structure MgS 4 With LaS 6 The octahedral structures are connected to form a three-dimensional cubic structure, such as Figure 2 As shown; the matrix has high symmetry and is easy to prepare large-sized crystals and transparent ceramics.

[0027] Pr was measured by spectrophotometer 3+ :MgLa 2 S 4 The transmittance of the crystal, such as Figure 3 As shown in Figure 1, there is a clear absorption peak at 1.53-1.66μm, and a mature LD pump at 1.55μm can be used. The Pr 3+ :MgLa 2 S 4 The mid-infrared emission spectrum of the crystal, such as Figure 4 As shown in the figure, it has a strong emission peak at 3.5-5.5μm. Therefore, a 1.55μm LD can be used to pump Pr 3+ :MgLa 2 S 4 The crystal outputs 3.5-5μm mid-infrared laser.

[0028] Other embodiments

[0029] The Pr provided in Example 1 3+ :MgLa 2 S 4 In contrast, the activation ion Pr3+ Replaced by Er 3+ 、Ho 3+ 、Dy 3+ Other rare earth ions such as Mg can be replaced by other elements of the same group such as Ca, Sr, and Ba, or La can be replaced by other elements of the same group such as Sc, Y, and Lu to obtain mid-infrared laser materials with similar performance. For those skilled in the art, referring to the content in Example 1, it is easy to obtain these other mid-infrared laser materials with similar performance.

[0030] Application Examples

[0031] A mid-infrared laser generating device, the structural schematic diagram of which is shown in Figure 5 As shown, it includes a laser pump source 1, and a resonant cavity arranged along the laser output optical path of the laser pump source; the resonant cavity includes an input mirror 2, a laser crystal 3 and an output mirror 4 arranged along the optical path. The laser pump source 1 adopts LD pumping with a wavelength of 1.32-1.71μm, preferably LD pumping with a wavelength of 1.55μm; the input mirror 2 has a high transmittance to 1.55μm light and a high reflectivity to the band selected for output in the 3.5-5μm band; the output mirror 4 has a high reflectivity to 1.55μm light and partially transmits the band selected for output in the 3.5-5μm band; the laser crystal 3 is preferably the Pr in Example 1. 3+ :MgLa 2 S 4 The working process is as follows: the LD pump source with a wavelength of 1.55μm enters the resonant cavity through the input mirror 2 and passes through the Pr 3+ :MgLa 2 S 4 The crystal excites the 3.5-5μm spectrum, oscillating in the resonant cavity to selectively output a specific wavelength band.

[0032] Obviously, the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A mid-infrared laser material, characterized in that: The mid-infrared laser material uses AELn2S4 as a matrix material and rare earth ions as activation ions; wherein: AE is Mg, Ca, Sr or Ba; Ln is La, Sc, Y or Lu.

2. The mid-infrared laser material according to claim 1, characterized in that: The rare earth ion is Pr 3+ , Er 3+ 、Ho 3+ or Dy 3+ .

3. The mid-infrared laser material according to claim 1, characterized in that: It is Pr 3+ :MgLn2S4.

4. A mid-infrared laser generating device, characterized in that: It comprises a laser pump source and a resonant cavity arranged along the laser output optical path of the laser pump source; the resonant cavity comprises an input mirror, a laser crystal and an output mirror arranged along the optical path; the laser crystal is a mid-infrared laser material as described in any one of claims 1 to 3.

5. The mid-infrared laser generating device according to claim 4, characterized in that: The laser pump source adopts LD pumping with a wavelength of 1.32-1.71 μm.

6. The mid-infrared laser generating device according to claim 5, characterized in that: The laser pump source adopts LD pumping with wavelengths of 1.32 μm, 1.55 μm, 1.60 μm and 1.71 μm.

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