Experimental Study Of Continuous Wave And Acousto-optic Q-switched Ho:SYSO Laser Pumped By LD

The 2?m high-power solid-state laser has a series of applications in many important technical fields,such as surgery,wind monitoring and mid-infrared frequency conversion.In the past 20 years,the Ho laser has become an ideal choice for obtaining 2 ?m band laser output.In this paper,a new type of single-doped Ho: SYSO crystal is used as a laser working substance to study the continuous wave and acousto-optic Q-switched LD pumped Ho: SYSO laser experimental study,which is expected to play a reference role in the subsequent research progress of 2 micron laser.The main research work has the following aspects.First,the research progress of 2?m solid-state laser is introduced,the difference of different Ho³⁺ doped matrix materials is compared,the research progress of various Ho³⁺ doped lasers is introduced,and the advantages of silicate for Ho³⁺ doped are pointed out.The research progress of 2?m acousto-optic Q-switched lasers is introduced.Then,the physicochemical and spectral properties of Ho:SYSO crystal were introduced.The absorption and emission spectra of Ho:SYSO crystal were measured with a spectrophotometer and a spectrometer,and then the stimulated absorption and emission cross sections were calculated according to the absorption and emission spectra.The numerical simulation of the gain cross section at different inversion particle ratios can provide a theoretical basis for the choice of pump source and laser design.The rate equations of Ho:SYSO laser continuous and acousto-optic Q-switched operation are established respectively,and the expression of the output power can be obtained by solving it.At the same time,the thermal effect of Ho:SYSO laser is also analyzed.Then,the laser is designed,the wavelength of the pump source can be determined by the absorption spectrum of the crystal,and the spot radius and beam quality of the pump source are selected.Next,the theory of the stability of the resonant cavity and the type of the resonant cavity are introduced,and the output mirror transmittance and cavity length that affect the stability of the resonant cavity are numerically analyzed to determine the best output mirror transmittance and the most suitable cavity long.The effect of the output mirror transmittance on the laser output power is discussed,and the laser heat dissipation system is introduced.Finally,an experiment was conducted.In the Ho:SYSO continuous laser,the output mirror transmittance was 15% and the absorbed pump power was 29.1W.A continuous laser output with a maximum output power of 13.0W and a wavelength of 2097.9nm was obtained.Keeping the transmittance of the output mirror unchanged at 15%,an acousto-optic Q-switching experiment was conducted.At a repetition frequency of 5 k Hz,a pulsed laser output with a maximum single pulse energy of 2.1 m J and a minimum pulse width of 21 ns was obtained.The calculated peak power is 100 k W.