| With the development of laser technology,pulse solid laser with stable performance and high output energy has entered the research field of scientists.The high water absorption coefficient of 2μm laser makes it have ultra-high precision in laser scalpel,and its high penetration ability makes it more convenient for long-distance transmission in lidar.Two-dimensional materials have been applied in various fields due to their excellent photoelectric characteristics,but the mainstream two-dimensional materials are still insufficient in the field of Q-switched.Therefore,SnSe2,which is less studied but has excellent optical properties,was selected to build a 2μm pulse solid laser,aiming at achieving higher laser output performance.In this thesis,the Q-switched theory for SnSe2 was studied.The expressions of peak power,single pulse energy and pulse width were calculated.Passive tuning Q coupling rate equation model was established.By changing pump pumping rate,reflectance of output mirror and initial transmittance of saturable absorber,the variation charts of pulse width,repetition frequency,single pulse energy and peak power were obtained.The abstract parameters of the basic theory were combined with the instrument parameters in the experiment to summarize the changing rules and guided the subsequent experiments.A 2μm passively Q-switched solid-state laser with SnSe2 as saturable absorber was constructed.SnSe2 was prepared by chemical vapor deposition.The material was characterized by Raman spectroscopy and atomic force microscopy,and the elemental composition and microscopic appearance were obtained.The saturation absorption characteristics of SnSe2 were measured by Tm,Ho:GdVO4 pulse laser.A Tm:YAP pulsed solid state laser with SnSe2 as a saturable absorber was built.The variation trends of repetition frequency,pulse width,single pulse energy and peak power at different pumping powers were calculated and optimized.The pulse width was compressed to the level of 100nanoseconds,which matched the numerical simulation results.It was proved that SnSe2 has great potential in the application of pulsed solid state laser. |
