Research On The Laser Output Performance Of Tm-Ho Co-doped LuVo₄

2?m wave band falls into the spectrum of atmospheric windw and locates in a region that is safe to human eyes;it is also at the absorption peaks of water molecules and human tissues.Therefore,2?m laser is an important source of optical measuring instruments,which is widely used in industry,medical,military and scientific research fields.Tm,Ho co-doped laser is an effective way to obtain 2?m wave band.The main work of this thesis is to study the laser output characteristics of the new Tm,Ho:LuVO₄ crystal by theory and experiments.Firstly,based on the absorption and fluorescence spectra of Tm,Ho:LuVO₄vanadate crystals obtained from experiments,the absorption cross sections and emission cross-sections of the Tm,Ho:LuVO₄ crystals is theoretically.Meanwhile,the quasi-four-level rate equation of Tm-Ho co-doping system is established according to the energy level transition mechanism of Tm and Ho ions.According to the crystal parameters,the performances of Tm,Ho:LuVO₄ laser are numerically simulated.The resonant cavity parameters and laser crystal parameters are analyzed according to the simulation results of the continuous laser output performance.Based on the parameters of the Tm,Ho:LuVO₄ laser,actively Q-switched operating of Tm,Ho:LuVO₄ crystal performance is numerically simulated.According to the simulation results,analyses are done about the influences of the actively Q-switched mode Tm,Ho:LuVO₄ laser crystal particle density,cavity output mirror transmittance,cavity loss on laser output pulse width,pulse energy and peak power.Based on numerically simulation of passively Q-switched mode Tm,Ho:LuVO₄,the influence factors of the output power,pulse width and pulse energy of the passively Q-switched mode Tm,Ho:LuVO₄ laser are analyzed.Secondly,according to the the resonant ABCD cavity matrix of Tm,Ho:LuVO₄ laser is established.The relationship between the stability of the cavity and the parameters of the cavity is systematically studied.Based on this,a continuous wave mode optical cavity of Tm,Ho:LuVO₄ laser is designed.The double-end pump design was used to carry out the continuous wave mode operation Tm,Ho:LuVO₄ laser experimental research.In the experiment,the LD with the center wavelength of 798.6nm was selected as the pump source of the laser.The continuous wave mode under the condition of liquid nitrogen refrigeration was studied operation Tm,Ho:LuVO₄ laser output coupling mirror transmittance,cavity length and other cavity parameters affect the laser output performance.When the output-coupling mirror with a transmittance of 30%,the cavity length of 155mm,and the pump power of 14.7W are selected,the maximum output power of the laser is 4.64W,and the corresponding slope efficiency and optical conversion efficiency output is 34.6%and 31.6%,respectively the output wavelength of the laser is 2075.72nm.This continuous wave mode operation Tm,Ho:LuVO₄ lasers are new type of laser source for medical devices.Finally,based on the research of Tm,Ho:LuVO₄ lasers in continuous wave mode,the actively and passively Q-switched mode Tm,Ho:LuVO₄ laser research was carried out.In the experimental study of active Q-switched Tm,Ho:LuVO₄lasers,the influence of the output coupling mirror transmittance,pulse repetition frequency,and pump powerof the acousto-optic Q-switched Tm,Ho:LuVO₄ lasers on the output performance of the laser was studied.Under the condition of output mirror transmittance of 30%,pulse repetition frequency of 10KHz and pump power of 14.7W,the maximum output power of Tm,Ho:LuVO₄ laser is 3.77W,and the corresponding slope efficiency and optical conversion efficiency output is 14%and 25.6%.At a pulse repetition rate of 1KHz the laser output has a narrowest pulse width of 69.9ns.The output wavelength of the laser is2075.72nm.This active Q-switched mode operation Tm,Ho:LuVO₄ lasers are new type of laser can be used to detect special materials.In the experimental study of Tm,Ho:LuVO₄ lasers in passively Q-switched mode,a novel saturated absorption mirror was designed with two-dimensional graphene as the saturated absorbing material.The output coupling mirror transmittance and the pump power of passively Q-switched mode Tm,Ho:LuVO₄ laser was studied the effect on the output performance of the laser.The Tm,Ho:LuVO₄ laser achieves a single pulse largest energy of 40.4?J,and its maximum output power is 1034mW,and the narrowest pulse width is 300ns.The output wavelength is 2057.03nm.This passively Q-switched mode Tm,Ho:LuVO₄ lasers can provide a new laser source for remote sensing monitoring.This study obtained a new continuous laser output and two new-pulsed laser outputs in the 2?m band,which provides three new high quality laser sources for medical instruments,material testing,and remote sensing monitoring.