Theoretical And Experimental Study On The Rate Equation Of The Composite Cavity Ho:YAG/SrWO₄ Raman Laser

2?m waveband solid-state lasers have wide application prospects in atmospheric monitoring,satellite remote sensing,electro-optical countermeasure,laser ranging,laser lidar and material analysis.At the same time,the 2?m waveband laser is still in the safety range of human eyes,showing amazing application potential in medical treatment.Stimulated Raman scattering(SRS)is an important frequency conversion method in the field of nonlinear optics.With the development and maturation of high-quality Raman crystals,the new wavelength laser which is difficult to be directly stimulated in laser crystal can be ptoducted by the SRS process.The output wavelength of the Raman laser is determined by the wavelength of the fundamental laser and the Raman frequency shift of the Raman crystal.Nowadays,solid-state Raman laser have shown an increasingly important role in the development of infrared spectroscopy.In this thesis,the Ho:YAG/SrWO4 Raman laser is resonantly pumped by a 1908nm Tm:YLF continuous wave laser,and the stable output of the Ho:YAG/SrWO4actively Q-switched Raman laser is finally realized.The main content includes two aspects as following:In theory,the theoretical model of quasi-two-level Ho:YAG/SrWO4 actively Q-switched Raman laser is established according to the energy transfer process of Ho ion in a resonantly pumped Ho:YAG laser,By the numerical simulation,the influences of Q-switch frequency and output mirror transmittance on the average output power,pulse width,pulse energy,and peak power of the Raman laser are analyzed.In experiment,to improve the absorption efficiency of pump energy,a laser diode pumped continuous wave Tm:YLF laser at 1908 nm is built at first,which has a maximum average output power of 9.5 W.Subsequently,the pulse output of Ho:YAG laser at 2122 nm is realized with an acousto-optic Q-switch.The narrowest fundamental pulse width of 40.2 ns is obtained at 9.5 W pump power.Finally,a coupled cavity with a linear configuration is adopted for the Ho:YAG/SrWO4 Raman laser.The stable output of the Raman laser is achieved when the 2?m output mirror is replaced by the Raman output mirror.When the pulse repetition frequency(PRF)is 4 k Hz and the pump power is 8.4 W,the stable average output power of 680 m W is obtained.The pulse width is 10.2 ns,the single pulse energy is 170?J,and the corresponding peak power is 16.67 k W.The centric wavelength of the Raman laser is monitored to be 2640 nm,and the Raman frequency shift is 925 cm^-1 compared with the fundamental laser at 2122nm.