| With the deterioration of global climate and environment in recent years, there is growing demand for data on atmospheric wind field all over the world. The use of coherent Doppler lidar for remote measurements of atmospheric wind fields is receiving increasing consideration as a valuable tool for studies of atmospheric dynamics. 2μm solid-state lasers are the primary choice for coherent Doppler wind detection for eye-safe properties and efficient diode-pump operation.Direct laser pumping of the Ho quasi-two-level laser offers several advantages over the sensitized Tm–Ho system: low quantum defect, elimination of energy transfer, reduced upconversion losses, high extraction efficiency. The combined advantages make a 2.1μm laser capable of high-power scaling and high energy output in room temperature. The work discussed in the thesis covers two areas: the single longitudinal mode operation of Tm pumped Ho:YAG CW and Q-switched laser.First, theoretically established CW output quasi two-level rate equations model and the active Q-switched model at low repetition frequency of Ho:YAG ring laser. The relationship between CW output laser output power and pumped power, and the expression of single pulse energy, pulse width, peak power of Q-switched output were derived.The operation of the nonplanar ring osillator is analyzed using polarization match theory. Single frequency output powers up to 6.3W at the wavelength of 2090.6nm with temperature tuning rate of -1.6GHz /℃for 19.7W of pump power are demonstrated. The frequency instability linear growth rate of 270Hz/μs was measured with fiber delayed self-heterodyne method. Taking the nonpanar ring laser as the seed laser using the seed-injection locked technology, the undirectional operation of Ho:YAG ring laser was realized, and a single a pulse energy of 11mJ, pulse width of 110ns, linewidth of 4.2MHz with diffraction limited beam quality of the single longitudinal mode Q-switched operation was achieved. |
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