CN-121983843-A - Thermally insensitive nanosecond pulse laser based on bonded crystal and multi-pass pumping structure

CN121983843ACN 121983843 ACN121983843 ACN 121983843ACN-121983843-A

Abstract

The application provides a thermally insensitive nanosecond pulse laser based on a bonding crystal and a multi-pass pumping structure, which belongs to the technical field of solid lasers, and comprises a resonant cavity consisting of the bonding crystal and a saturable absorber, wherein the bonding crystal is used as a gain medium and is in a right trapezoid prism shape, the bonding crystal comprises a cuboid-shaped doped crystal and a right triangle prism-shaped undoped crystal, the doped crystal and the undoped crystal are bonded, all optical surfaces of the bonding crystal are polished, and the fully polished surface and the right trapezoid structure of the bonding crystal are utilized to naturally form a Z-shaped multi Cheng Bengpu optical path based on total internal reflection, so that the effective absorption path of pump light is prolonged by a plurality of times, the traditional active compensation mechanism of controlling temperature to stabilize wavelength is abandoned, and the passive compensation mechanism of prolonging the path to compensate absorption is adopted, thereby solving the temperature sensitivity problem of the LD pumping laser by skillfully utilizing the optical principle.

Inventors

WANG CHAO
ZHANG PEIFENG
DAI YINGYING
Shen Botong
ZHANG YU
NIU ZHICHUAN

Assignees

山西创芯光电科技有限公司

Dates

Publication Date: 20260505
Application Date: 20251231

Claims (9)

1. A thermally insensitive nanosecond pulse laser based on a bonding crystal and a multi-pass pumping structure is characterized by comprising a resonant cavity composed of the bonding crystal and a saturable absorber, wherein the bonding crystal is used as a gain medium and is in a right trapezoid prism shape, the bonding crystal comprises a cuboid-shaped doped crystal and a right triangle prism-shaped undoped crystal, the doped crystal and the undoped crystal are bonded, and all optical surfaces of the bonding crystal are polished.
2. The thermally insensitive nanosecond pulse laser based on the bonded crystal and the multipass pumping structure of claim 1 further comprising a pumping module, the pumping module being an LD array matching the length of the bottom of the right trapezoid surface of the bonded crystal.
3. The thermally insensitive nanosecond pulse laser based on the bonded crystal and the multipass pumping structure of claim 2, wherein the pumping light emitted by the pumping module is incident to the side surface at an angle larger than a critical angle in the bonded crystal, and total internal reflection occurs, so that zigzag multiple turn-back propagation is performed in the crystal along the trapezoid height direction.
4. A thermally insensitive nanosecond pulse laser based on bonded crystals and multipass pumping structures as claimed in any one of claims 1-3, characterized in that the doped crystal is an Nd: YAG doped crystal.
5. The thermally insensitive nanosecond pulse laser based on bonded crystal and multipass pumping structure of claim 4 wherein the undoped crystal is pure YAG crystal.
6. The thermally insensitive nanosecond pulse laser based on bonded crystal and multipass pumping structure of claim 5 wherein two right trapezoid surfaces of bonded crystal are used as end surfaces, and resonator films are plated on both end surfaces.
7. A thermally insensitive nanosecond pulse laser based on bonded crystal and multipass pumping structures as claimed in claim 1 or 2, wherein the saturable absorber is Cr-YAG crystal.
8. The thermally insensitive nanosecond pulsed laser based on bonded crystals and multi-pass pumping structures of claim 7 wherein the bonded crystals and the saturable absorber form a slab-slab or slab-concave resonant cavity.
9. A thermally insensitive nanosecond pulsed laser based on bonded crystals and multipass pumping structures as set forth in claim 5, 6 or 8, wherein the laser is used in a broad temperature range of-40 ℃ to +60 ℃.

Description

Thermally insensitive nanosecond pulse laser based on bonded crystal and multi-pass pumping structure Technical Field The application relates to the technical field of solid lasers, in particular to a thermally insensitive nanosecond pulse laser based on a bonding crystal and a multi-pass pumping structure. Background The pulse laser range finder has the core requirements on a light source that stable nanosecond pulses are output, the environment adaptability is good (especially in a wide temperature range), the structure is compact, and the reliability is high. At present, a Nd-YAG/Cr-YAG passive Q-switched laser adopting LD pumping is one of the mainstream technical schemes. However, this approach faces a key challenge in that the emission wavelength of the Laser Diode (LD) is temperature sensitive. As the ambient temperature changes (e.g., -40 ℃ to +60 ℃), the emission wavelength of LD shifts, while the absorption peak of Nd: YAG crystal is narrower (around 808 nm). Wavelength drift can lead to significant degradation in absorption efficiency of pump light, which in turn can cause unstable laser output energy and even flameout. To solve this problem, the prior art generally requires an active temperature control system (e.g., TEC semiconductor refrigerator) for the LD, but this increases the complexity, power consumption, volume and cost of the system. Therefore, there is a strong need in the art for a laser ranging light source that can operate stably over a wide temperature range without the need for complex active temperature control. Disclosure of Invention In order to overcome the defects that the traditional LD pumping passive Q-switched laser is sensitive to temperature and depends on active temperature control, the application provides a thermally insensitive nanosecond pulse laser based on a bonding crystal and a multi-pass pumping structure. The application adopts the technical scheme that the thermally insensitive nanosecond pulse laser based on the bonding crystal and the multi-pass pumping structure comprises a resonant cavity composed of the bonding crystal and a saturable absorber, wherein the bonding crystal is used as a gain medium and is in a right trapezoid prism shape, the bonding crystal comprises a cuboid-shaped doped crystal and a right triangle prism-shaped undoped crystal, the doped crystal and the undoped crystal are bonded, and all optical surfaces of the bonding crystal are polished. Further, the laser bonding device also comprises a pumping module, wherein the pumping module is an LD array matched with the lower bottom length of the right trapezoid surface of the bonding crystal. Further, the pump light emitted by the pump module is incident to the side surface at an angle larger than a critical angle in the bonding crystal, and total internal reflection occurs, so that multiple turn-back propagation is performed in the crystal along the trapezoid height direction. Further, the doped crystal adopts Nd-YAG doped crystal. Further, pure YAG crystals are used as undoped crystals. Further, two right trapezoid surfaces of the bonding crystal are used as end surfaces, and resonant cavity films are plated on the two end surfaces. Further, the saturable absorber adopts Cr-YAG crystal. Further, the bonded crystal and the saturable absorber form a flat-flat or flat-concave resonant cavity. Further, the laser is used in a wide temperature range of-40 ℃ to +60 ℃. Compared with the prior art, the application has the following beneficial effects: 1) The absorption length is greatly prolonged by the multi-process pump, the absorption efficiency reduction caused by wavelength drift caused by temperature is fundamentally compensated, and the stable operation of a wide temperature range (-40 ℃ to +60 ℃) under the condition of no active temperature control is realized. 2) The portable distance measuring device has the advantages of simple structure, high reliability, no need of components such as TEC, thermistor, temperature control circuit and the like, greatly simplified system structure, reduced power consumption, more compact volume, remarkably improved reliability and suitability for portable distance measuring devices sensitive to power consumption and volume. 3) The pump efficiency is high, the multi-pass pump structure enables pump light to be fully absorbed, and the light-light conversion efficiency is improved. 4) The method has good industrialization prospect, mature bonding crystal technology, easy realization of modularized production and encapsulation and controllable cost. Drawings The application is further described below with reference to the accompanying drawings: FIG. 1 is a schematic three-dimensional structure of a bonded crystal according to an embodiment of the present application, showing a right trapezoid shape and a bonding interface, wherein a is a bottom surface of the bonded crystal and b is a front surface of the bonded crystal; fig. 2 is a schematic diagram of a p