CN212323401U

CN212323401U - Miniaturized human eye safety laser

Info

Publication number: CN212323401U
Application number: CN201922269092.4U
Authority: CN
Inventors: 王万祎; 赵子竣; 王杰; 丁戗; 曾璞; 胡少沛; 温锋; 余吉庆; 张治旭; 孙子泰; 刘乙洁; 张祎景; 公丕华; 黄颖全; 陈方军
Original assignee: South West Institute of Technical Physics
Current assignee: South West Institute of Technical Physics
Priority date: 2019-12-17
Filing date: 2019-12-17
Publication date: 2021-01-08
Anticipated expiration: 2029-12-17

Abstract

The utility model discloses a be applied to laser rangefinder's miniaturized people's eye safety laser instrument, the utility model discloses a following technical scheme realizes: adopts the glass and crystal composite technology to add the gain medium Er³⁺/Yb³⁺Co-doped phosphate glass and passively Q-switched saturable Co²⁺：MgAl₂O₄The crystal is subjected to optical thermal recombination, and the composite material is reducedThe temperature gradient in the medium can be increased, so that the thermal focal length is lengthened, the mode volume is increased, and the quality of laser beams is improved; in addition, the composite material reduces the loss in the cavity, improves the particle number density in the cavity, narrows the pulse width and increases the output energy, thereby improving the performance of the laser. The utility model discloses a natural passive refrigerated mode makes the structure of whole laser more simple, compact, adopts the LD single tube laser terminal surface pumping of central wavelength 940nm, is adapted to wide temperature application range.

Description

Miniaturized human eye safety laser

Technical Field

The utility model belongs to the technical field of energy photoelectron and solid laser, a miniaturized human eye safety laser is related to.

Background

1.5 μm wavelength laser is in the communication window, and has wide application in the field of optical communication; meanwhile, laser with the wavelength of 1.5 mu m is positioned in a wave band insensitive to human eyes, and the smoke penetration capability is strong, so that the laser has great application potential. In particular to a 1.5 mu m wave band micro pulse laser with small volume, low power consumption, wide temperature adaptation range, high stability and low cost, and has wide application prospect in the laser ranging field of unmanned aerial vehicles, ranging telescopes, military affairs and the like.

At present, three technical methods for outputting 1.5-micron wavelength eye-safe laser are available: optical Parametric Oscillation (OPO), Stimulated Raman Scattering (SRS), and direct output. The OPO and SRS are usually obtained by converting a laser beam of 1.06 μm to a frequency, which results in a complicated system structure, is not suitable for military applications such as individual combat, and is also relatively expensive, which is not suitable for mass production. The direct output 1.5 μm laser is easy to be miniaturized compared with OPO and SRS, so that the method is the most ideal method for mass production and application. The direct output of 1.5 μm laser includes two modes, one is direct output of a semiconductor laser, and the other is obtained by pumping a gain medium through the semiconductor laser. The laser diode has poor beam quality, the semiconductor material is easily affected by temperature, and the stability is not high. The most common way to obtain the eye safety laser with 1.5 μm direct output is the LD pumped erbium glass, because the erbium-ytterbium co-doped phosphate glass has the characteristics of long upper energy level lifetime, high erbium-ytterbium energy transfer efficiency, difficult generation of fluorescence quenching, and the like, and the production condition is mature, and the LD pumped erbium glass is the most commonly used gain medium for directly outputting the eye safety laser with 1.5 μm low repetition frequency at present.

Currently, there are two main ways of LD-pumped erbium glass lasers, end-pumped and side-pumped. According to research, the side pumping mode mostly adopts an LD double-side pumping erbium glass plate strip mode, the mode can obtain single-pulse energy millifocal level laser output with the pulse width of about 10ns and the output of 1.5 mu m laser, but the mode of large-area conduction cooling is adopted, and very large temperature gradient exists in the thickness direction, so that wave front distortion, thermal birefringence and thermal lens effect are easily generated, therefore, the light beam quality is poor, and an external circulating water cooling system is required, so that the laser is huge in size and is very inconvenient to carry and use.

SUMMERY OF THE UTILITY MODEL

Objects of the invention

The utility model aims at: on the basis of an LD end-pumped erbium glass laser, a miniaturized eye-safe laser with better beam quality and higher light-light conversion efficiency is provided.

(II) technical scheme

In order to solve the technical problem, the utility model provides a miniature people's eye safety laser instrument, it includes by preceding pumping source 2 to the coaxial arrangement in back, focusing lens 3, transfer Q crystal 4, gain medium 5, transfer Q crystal 4 and gain medium 5 to pass through the light beam thermal recombination and form the combined material module, the front side of pumping source 2 arranges totally reflecting mirror 1, and the output mirror is arranged to the combined material module rear side.

The pumping source 2 is a TO-3 packaged LD, and the central wavelength is 940 nm.

The diameter of a waist spot on the light emitting surface of the pump source 2 is 250 micrometers, the fast axis divergence angle is smaller than 35 degrees, the slow axis divergence angle is 10 degrees, and the fast axis adopts an optical fiber fast axis collimating mirror with a 940nm antireflection film plated on the surface to compress the divergence angle.

Wherein, the total reflection mirror 1 is anti-reflection at 940nm and total reflection at 1535 nm.

Wherein the output mirror 6 has a transmittance of 10% at a wavelength of 1535 nm.

Wherein, the Q-switched crystal 4 is Co2 +: MgAl2O4 crystal with length of 1.6 mm; the gain medium 5 is Er3+/Yb3 +: glass, 3.0mm in length; the size after compounding is phi 1mm multiplied by 4.6 mm.

The composite material module is characterized in that one surface, close to the total reflection mirror, of the composite material module is plated with anti-reflection films with wavelengths of 940nm and 1535nm, one surface, close to the output mirror, of the composite material module is plated with anti-reflection films with wavelengths of 940nm and 1535nm, the cavity length is 4.6mm, the pumping pulse width is 7ms, and the repetition frequency is 10 Hz.

Wherein the laser cavity type is a flat-flat cavity.

(III) advantageous effects

The miniaturized eye safety laser provided by the technical scheme adopts a diode laser end with the central wavelength of 940nmThe laser output of 1.5 μm is obtained by surface pumping erbium glass, passively adjusting Q, and naturally and passively cooling, and the gain medium Er is used³⁺/Yb³⁺: /glass and passively Q-switched crystal Co²⁺：MgAl₂O₄The optical thermal compounding is carried out, the loss in the cavity is reduced, the particle number density in the cavity is improved, the single pulse output energy is increased, the output pulse width is reduced, the beam quality of output laser is improved, meanwhile, a natural cooling mode is adopted, the traditional huge cooling system is avoided, and the size of the whole laser is reduced by a large degree.

Drawings

Fig. 1 is a schematic diagram of a miniature eye-safe laser.

Fig. 2 is a schematic diagram of a micro eye-safe laser structure.

Detailed Description

In order to make the objects, contents, and advantages of the present invention clearer, the following description of the embodiments of the present invention will be made in detail with reference to the accompanying drawings and examples.

As shown in fig. 1 and 2, the utility model discloses miniature people's eye safety laser includes by preceding pumping source 2 to back coaxial arrangement, focusing lens 3, transfer Q crystal 4, gain medium 5, transfers Q crystal 4 and gain medium 5 to pass through the compound composite material module of light beam thermal recombination formation, the front side arrangement total reflection mirror 1 of pumping source 2, the output mirror is arranged to the composite material module rear side.

The laser of the embodiment adopts an end-face pumping mode, the pumping source 2 is a TO-3 packaged LD with a center wavelength of 940nm, compared with a wavelength of 976nm, Yb³⁺The absorption cross section around 940nm wavelength has small change with temperature, when the wavelength of the pump light is shifted, the laser output does not change too much, which is beneficial to the stability of the ultrahigh laser; the diameter of a waist spot on a light emitting surface of the LD is 250um, the fast axis divergence angle is smaller than 35 degrees, the slow axis divergence angle is 10 degrees, the fast axis adopts an optical fiber fast axis collimating mirror with a 940nm antireflection film plated on the surface to compress the divergence angle, a focusing lens 3 with the focal length of 5mm is adopted for focusing, and the beam waist of the focused light spot is about 80 um.

The laser cavity type is flat-flat cavity, total reflection mirror 1 is anti-reflection to 940nm and total reflection to 1535nm, and output mirror 6 has a transmittance of 10% to 1535nm wavelength.

In the composite material module, the Q-switched crystal 4 is Co²⁺：MgAl₂O₄A crystal having a length of 1.6 mm; the gain medium 5 is Er³⁺/Yb³⁺: glass, 3.0mm in length; the size after compounding is phi 1mm multiplied by 4.6 mm. One surface of the composite material module close to the total reflection mirror is plated with anti-reflection films with the wavelengths of 940nm and 1535nm, one surface of the composite material module close to the output mirror is plated with a total reflection film with the wavelengths of 940nm and an anti-reflection film with the wavelengths of 1535nm, the cavity length is 4.6mm, the pumping pulse width is 7ms, and the repetition frequency is 10 Hz.

According to the above technical scheme, the utility model has the following characteristics of showing:

(1) the end-face pumping of the LD single-tube laser with the central wavelength of 940nm is adopted, so that the wide temperature use range is adapted;

(2) the gain medium and the passive Q-switched crystal are subjected to optical thermal compounding, and compared with a traditional structure that the gain medium and the passive Q-switched crystal are separated, the thermal deposition of erbium glass can be reduced by adopting a compounding technology, the thermal depolarization and the end face deformation are reduced, the loss in a cavity is reduced, and the particle number density in the cavity is improved, so that the single-pulse output energy is increased, the output pulse width is reduced, and the beam quality of output laser is improved;

(3) the laser adopts a natural passive cooling mode, so that the structure of the whole laser is simpler and more compact.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be considered as the protection scope of the present invention.

Claims

1. The miniaturized human eye safety laser is characterized by comprising a pumping source (2), a focusing lens (3), a Q-switched crystal (4) and a gain medium (5) which are coaxially arranged from front to back, wherein the Q-switched crystal (4) and the gain medium (5) are thermally compounded through light beams to form a composite material module, a total reflection mirror (1) is arranged on the front side of the pumping source (2), and an output mirror is arranged on the rear side of the composite material module.

2. Miniaturized human eye safe laser according TO claim 1, characterized in that the pump source (2) is a TO-3 package LD with a center wavelength of 940 nm.

3. The miniaturized human eye safe laser device according to claim 2, wherein the diameter of the waist spot of the light emitting surface of the pump source (2) is 250um, the fast axis divergence angle is less than 35 degrees, the slow axis divergence angle is 10 degrees, and the fast axis adopts the compression divergence angle of the optical fiber fast axis collimating mirror with the surface plated with 940nm antireflection film.

4. A miniaturized human eye safe laser according to claim 3, characterized in that the total reflection mirror (1) is anti-reflective at 940nm and totally reflective at 1535 nm.

5. A miniaturized human eye-safe laser according to claim 4, characterized in that the output mirror (6) has a transmission of 10% at a wavelength of 1535 nm.

6. Miniaturized human eye safe laser according to claim 5, characterized in that the Q-switched crystal (4) is Co2 +: MgAl2O4 crystal with length of 1.6 mm; the gain medium (5) is Er3+/Yb3 +: glass, 3.0mm in length; the size after compounding is phi 1mm multiplied by 4.6 mm.

7. The miniaturized human eye safe laser of claim 6, wherein the surface of the composite module near the total reflection mirror is plated with anti-reflection films with wavelengths of 940nm and 1535nm, the surface near the output mirror is plated with anti-reflection films with wavelengths of 940nm and 1535nm, the cavity length is 4.6mm, the pumping pulse width is 7ms, and the repetition frequency is 10 Hz.

8. The miniaturized eye-safe laser of claim 1, wherein the laser cavity type is a plano-plano cavity.