| The 2?m band is the window for atmospheric transmission,and it is also a safety band for the human eye.In particular,this band covers many molecules' absorption peaks(such as H2 O,CO2,NO2,etc.).Due to these special properties,lasers with an emission wavelength of 2 ?m are widely used in the fields of laser communication,medical care,and air pollution monitoring.In recent years,with the development of various application technology fields,it is of great practical significance to continuously explore the new type of single-doped Ho laser operating at room temperature.In this dissertation,a novel single-doped Ho:SYSO mixed crystal was chosen as the research object,and the research work on the novel 2 ?m laser characteristics of the new Ho:SYSO mixed crystal was carried out in the following aspects.First,the spectral characteristics of the Ho:SYSO crystal were studied using the Mc Cumberland Judd-O felt theory.The absorption spectrum of the Ho:SYSO crystal measured at room temperature was used to calculate the effective emission cross section of the crystal,and the lifetime of the crystal energy level was calculated.Finally,the gain cross-section of the crystal is calculated from the emission cross-section and the absorption cross-section,and compared with Ho:SSO crystals with the same doping concentration.The results show that the strongest absorption peak of Ho:SYSO crystal is at 1944 nm,the stimulated absorption cross section is 1.24×10-20cm2,the strongest emission peak is at nm,and the stimulated emission cross section is 2.13×10-20cm2.The peak half maximum width is 114 nm.The lifetime of 5I7 is 1.9ms.In theory,based on a quasi-two-level velocity equation model of a single-doped Ho laser,The relationship between the number of saturated inversion particles,the number of threshold inversion particles,and the temperature was analyzed.It also analyzes the influence of parameters such as output mirror transmittance on output power.By establishing the heat conduction equation of the crystal,the temperature distribution of the crystal during operation is solved,and the relatio nship between the thermal lens of the crystal and the pump power is calculated.The results show that when working at room temperature thermal focal length fth>150mm;pump power of 15 W,the maximum temperature difference within the crystal(35)T = 16 °C.Experimentally,the effects of different transmittances on the output power and output spectrum of Ho:SYSO lasers were studied.In addition,the length of the resonant cavit y and the effect of the operating temperature of the crystal on the laser output have also been investigated.At a temperature of 283 K,T=11.7%,and a pump power of 12.8W,an output wavelength near 210 8.5 nm was obtained,the output optical power was 1.88 W,the corresponding slope efficiency was 14.1%. |
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