周期极化晶体光参量过程的调谐特性分析

Tuning Characteristics of Periodically Poled Crystals in Optical Parameter Process

以周期极化晶体MgO…sPPLT为研究对象,根据该晶体的折射率随波长、温度变化的色散方程及极化周期随温度的热膨胀关系,并紧密结合频率变换过程中的能量守恒条件,给出详细算法,得到了532nm抽运光的光参量过程近红外波段温度调谐特性。通过增加极化周期,进一步得到1064nm抽运该晶体的光参量过程中红外波段温度不敏感特性。调整或忽略极化周期项,更换晶体的色散方程,该研究方法可推广到其他准相位匹配或相位匹配非线性晶体的参量变换调谐特性研究。

The temperature-tuning characteristic of periodically poled crystal, taking MgO：sPPLT as an example, in the optical parameter process in the near infrared range with 532 nm pumping laser is studied by considering Sellmeier equation for the change of crystal refractive index with wavelength and temperature, the thermal expansion of poled period with temperature, and the energy conservation condition during frequency conversion process. By increasing the poled period, the non-temperature-sensitive characteristic at the mid-infrared range with 1064 nrn pumping laser is also obtained. Just by adjusting or ignoring the poled period term, and replacing the crystal dispersion equation, the method can be easily extended to other quasi-phase matched or phase-matched nonlinear crystals.