| The 3?m band mid-infrared laser has important applications in medical,remote sensing,atmospheric environmental monitoring,and optoelectronic countermeasures.As the medical industry continues to advance and people's health requirements continue to escalate,the 3?m band lasers have a growing role in the medical industry,especially in dentistry and surgery,due to their strong absorption of water.In the atmospheric detection scheme,3?m is very sensitive to the detection of water vapor changes in the atmosphere and can be used as a good tool for environmental monitoring.In addition,the 3?m band laser has important applications in the development and development of optoelectronic countermeasures and laser radar because it can be used as a pump source for mid-infrared lasers.The research on the laser output of 3?m band doped with Ho3+is still in its infancy.In recent years,the crystals of Ho3+and Pr3+doped with LiLuF4 are grown by Czochralski method,and the laser of 3?m band is successfully output.As a new means of outputting lasers in the 3?m band,it is meaningful to study the output characteristics of the gain switch Ho,Pr:LLF laser.Therefore,the research content of this paper can be summarized as the following parts:Firstly,based on the physical and spectral properties of Ho,Pr:LLF crystals,the energy level structure and ion tra nsition mechanism of Ho3+ions are studied.The three-level system rate equation of Ho,Pr:LLF laser is established,and the linear cavity Ho,Pr:LLF laser stablished.The effect of different output mirror tra nsmittances on the output characteristics of LLF lasers is analyzed.Secondly,according to the upper level characteristics of Ho,Pr:LLF crystal,combined with the characteristics of gain switch,KTP optical parametric oscillator is built as the pump source of Ho,Pr:LLF laser.Based on the nonlinear crystal quasi-phase matching condition,the crystal cutting angle of the 1190 nm laser is calculated under the 532 nm laser pumping condition of KTP crystal.The cavity shape of KTP optical parametric oscillator is designed by simulation,and the KTP optical parametric is simulated.The distribution of the spot in the cavity of the oscillator.Combined with the simulation,the laser output with the maximum output single pulse energy of 4.4 mJ,pulse width 8.2 ns,and center wavelength of 1191.9nm was obtained through experiments.The experimental results were measured and demo nstrated.Finally,the Ho,Pr:LLF laser is built,and the cavity design of the Ho,Pr:LLF laser is designed.The cavity length is obtained by simulation using the flat-concave cavity.In normal operation,the laser output with a maximum output single pulse energy of 102?J,a laser pulse width of 33 ns,a center wavelength of 2958 nm,and a peak power of up to 3.1 kW is obtained.The light-to-light efficiency and pump slope efficiencies were 1.5%and 2.6%,respectively.Under optimal output conditions,the output laser pulse width varies from 96 ns to 33 ns as a function of pump energy.Based on the pulse timing of the 1.19?m laser and the 2.95?m laser output from the pump source,the gain switching characteristics of the Ho,Pr:LLF laser are analyzed in depth from the characteristics of the gain switch,and the experimental analysis results are given.In this paper,the output characteristics of the new crystal Ho,Pr:LLF solid-state laser are studied.At the same time,the laser output with the highest peak power in such research is obtained,which has certain value for the research and application of3?m laser. |
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