The Theoretical And Experimental Research Of Microchip Laser

Laser diode (LD) pumped microchip lasers have many advantages such as compactness,light weight, high efficiency, reliability, good beam quality and long lifetime, etc. SinceLD-pumped microchip lasers easily realize single-longitudinal-mode laser output, they are ofgreat interesting in the field of space optical communication, laser radar, non-linear opticsand biomedicine, etc. Dual-frequency microchip lasers combining the common advantages ofmicrochip laser with large frequency-difference, tunable and dual-wavelength stability, isvery useful in the field of ROF system and laser precision measurement system.This thesis mainly studies the spatial characteristics, temporal characteristics ofsingle-longitudinal-mode microchip laser; as well as the temporal characteristics and spectralproperties of dual-frequency microchip laser, theoretically and experimentally. The maincontents are as follows:(1)Considering the gain (loss)-guiding and quadratic index-guiding (including thermalguiding and concave mirror guiding), introducing the complex refractive index, one achievesthe self-reproduce modes of microchip laser. The influences of the different pumpingparameters to the output transverse-mode profile in the near-field are discussed.(2)The theoretical model of Cr4+:YAG crystal passively Q-switched microchip laser isimproved. By comparing numerical calculation and experimental results, one concludes therelationship among the continuous pumping rate, pulse pumping rate and the width of pumppulse, and the relationship of single-pulse width, peak power vs. the overall pumping rate,with stable and controllable laser pulse train output. By using pre-pumping technique, thehighly stable Q-switched laser pulses with repetition rate from 1Hz to 4kHz is acquired,experimentally.(3)The pre-pumping theoretical model of gain-switching microchip laser is established.By comparing numerical calculation and experimental results, one finds the way forincreasing the peak power of pulse under single pulse output condition. Stable pulse peakpower of 6W, duration of 24ns and repetition rate of 1Hz~10kHz is obtained, experimentally.(4)The theory of single-longitudinal-mode dual-wavelength output of microchip laser isestablished, By applying the theory to LD-pumped Nd:YVO4microchip laser, one gets stabledual-wavelength laser train output with the center wavelength in 1064.18nm and 1064.50nm,respectively. The space of two wavelengths is 0.32nm, correspond to 85GHz. Finally, thefeasibility of the dual-frequency microchip laser used to photonic generation of millimeter wave is analysed, and one obtains that the dual-frequency microchip laser can used tophotonic generation of millimeter wave.