Yan Xingpeng, Liu Qiang, Wang Dongsheng, Gong Mali
Center for Photonics and Electronics, State Key Laboratory of Tribology, Department of Precision Instruments, Tsinghua University, Beijing, China.
Opt Express. 2011 Mar 28;19(7):6883-902. doi: 10.1364/OE.19.006883.
A theoretical model as well as the experimental verification of the combined guiding mechanism for the transverse mode formation in the end-pumped laser resonator are investigated. The nonlinear Schrödinger-type wave equation in the gain medium is derived, in which the combined guiding mechanism: the thermal induced refractive index guiding effect as well as the gain guiding effect, is taken into account. The gain saturation and spatial hole burning are considered. The split step Fourier method is used to solve the nonlinear wave equation. A high power end-pumped Nd:YVO4 laser resonator is built up. After establishing the pump absorption model of our laser resonator, the temperature distribution in the gain medium is obtained by the numerical solving of the heat diffusion equation. The combined guiding effect is first observed in the end-pumped Nd:YVO4 laser resonator, and the experimental transverse mode profiles well agree with the theoretical prediction from the derived nonlinear Schrödinger-type wave equation. The geometric design criterion of the TEM00 mode laser is compared with our wave theory. The experimental- and theoretical- results show that our wave theory with the combined guiding mechanism dominates the transverse mode formation in high power end-pumped laser resonator.
研究了端面泵浦激光谐振腔中横向模式形成的组合导光机制的理论模型及实验验证。推导了增益介质中的非线性薛定谔型波动方程，其中考虑了组合导光机制：热致折射率导光效应以及增益导光效应。考虑了增益饱和和空间烧孔。采用分步傅里叶方法求解非线性波动方程。搭建了高功率端面泵浦Nd:YVO4激光谐振腔。建立激光谐振腔的泵浦吸收模型后，通过数值求解热扩散方程得到增益介质中的温度分布。在端面泵浦Nd:YVO4激光谐振腔中首次观察到组合导光效应，实验横向模式分布与从推导的非线性薛定谔型波动方程得到的理论预测结果吻合良好。将TEM00模激光器的几何设计准则与我们的波动理论进行了比较。实验和理论结果表明，具有组合导光机制的波动理论主导了高功率端面泵浦激光谐振腔中的横向模式形成。
