影响CO_2激光准相位匹配倍频效率的理论研究

Theoretical Investigation on Quasi-Phase-Matched SHG Efficiency Effects of CO_2 Laser

对影响CO2激光准相位匹配倍频效率的因素进行了研究,利用非线性耦合波动方程,分析了在不同基频光功率密度条件下,倍频过程中晶体吸收、界面损耗、周期长度误差和温度变化对倍频效率的影响;对制备高效率CO2激光倍频晶体的误差容限参数进行了计算。当基频光强度为25MW/cm2,晶体键合层数为60层时,必须将每层界面损耗控制在0.5%以下,周期长度误差控制在1μm以内,能保证理论倍频效率40%,为准相位匹配晶体的制备参数的确定提供理论依据。

The factors which have effect on the efficiency of CO2 laser frequency doubling were researched. Under conditions of different fundamental intensity, the factors such as crystal absorption, interface loss, errors of period and temperature changing were analyzed. The errors tolerance of high efficiency CO2 frequency doubling crystal manufacturing was calculated. When the fundamental intensity is 25 MW/cm2 and the layers of stack is 60,the interface loss per layer must be lower than 0.5% ,and the errors of period must be lower than per layer,then the efficiercy would be higher than 40%. Provide theorical basis for pa rameters of quasi-phase-matched crystal manufacturing.