Design,Fabrication And Performance Of 532nm Solid-State Laser With High Stability And Wide Temperature

Aerosol is an important part of the atmosphere.Although it occupies a low proportion in the atmosphere,its role can directly or indirectly affect the radiation balance of the atmosphere,which brings great uncertainty to climate change and assessment.In addition,the existence of a large number of aerosols also seriously affects the health of human life.Therefore,the detection of aerosol has been paid more and more attention in recent years.In this paper,the lidar light source for aerosol detection is studied,and a micro-pulse green laser is prepared by air cooling technology,which can be applied to lidar for aerosol detection.Firstly,this paper introduces the research progress of stability and thermal effect of all-solid-state green laser at home and abroad.Secondly,the frequency conversion theory,the conversion efficiency of frequency doubling crystals,the physical and chemical properties of several common nonlinear crystals and the selection of nonlinear crystals are introduced.In addition,the heat conduction theory,the boundary conditions needed to solve the heat conduction equation,the thermoelastic theory,the misalignment sensitivity and other related theoretical knowledge are introduced.In order to solve the problems of unstable output power and harsh environment of laser radar in practical application.In this paper,a solid-state green laser with high stability and wide temperature is designed and fabricated using laser crystal Nd:YAG as working medium.Firstly,the optical path for measuring the thermal focal length of laser crystal is set up,and different positions of different laser crystals are pumped by different types of pump power supply to measure the thermal focal length.The research shows that the thermal effect of laser crystal with continuous pump power supply,3×3×15mm~3doping concentration of 0.6at.%,0.63mm pump spot and 2mm laser crystal is small.In addition,the cavity structure of plano-convex cavity is designed to compensate the thermal effect of laser crystal.The experimental systems of frequency doubling crystals with different lengths of 3×3×4mm~3,3×3×8mm~3and 3×3×12mm~3were set up.The output power and frequency doubling efficiency of the frequency doubling crystals were tested and analyzed.The results show that the frequency doubling crystals with a length of 3×3×8mm~3are more suitable for high stability and wide temperature solid-state lasers.At the same time,the heat sink and air-cooling fan are designed,and the simulation analysis is carried out by Solid Works.The results show that the maximum working temperature of the laser is 62.85℃,and the maximum wind speed of the laser is 8.414m/s when it works normally,which achieves the heat dissipation effect of the laser and meets the expected standard.Finally,the performance of the prepared laser was tested by beam quality analyzer,CCD camera,digital oscilloscope,high and low temperature box and other instruments.The results show that the laser can work normally at 0～50℃,and the repetition rate can be adjusted from 3 k Hz to 7k Hz.Under normal working conditions,the output power is 2.8W,the power stability is 0.52%,the beam quality isM_x~2(28)1.198、M_y~2(28)1.134,the pulse width is 12.17ns,the ellipticity is 0.94,the divergence angle is about 0.1mrad,and the beam directivity is about 10urad.