Liqing Ren, Yongfang Li, Baihong Li, Lei Wang, Zhaohua Wang
School of Physics and Information Technology, Shaanxi Normal University, Xi'an, China.
Opt Express. 2010 Sep 13;18(19):20428-38. doi: 10.1364/OE.18.020428.
Based on the dressed state formalism, we obtain the adiabatic criterion of the sum frequency conversion. We show that this constraint restricts the energy conversion between the two dressed fields, which are superpositions of the signal field and the sum frequency field. We also show that the evolution of the populations of the dressed fields, which in turn describes the conversion of light photons from the seed frequency to the sum frequency during propagation through the nonlinear crystal. Take the quasiphased matched (QPM) scheme as an example, we calculate the expected bandwidth of the frequency conversion process, and its dependence on the length of the crystal. We demonstrate that the evolutionary patterns of the sum frequency field's energy are similar to the Fresnel diffraction of a light field. We finally show that the expected bandwidth can be also deduced from the evolution of the adiabaticity of the dressed fileds.
基于缀饰态形式理论，我们得到了和频转换的绝热判据。我们表明，这一约束限制了两个缀饰场之间的能量转换，这两个缀饰场是信号场和和频场的叠加。我们还表明，缀饰场的布居数演化，反过来描述了在通过非线性晶体传播期间光光子从种子频率到和频的转换。以准相位匹配（QPM）方案为例，我们计算了频率转换过程的预期带宽及其对晶体长度的依赖性。我们证明，和频场能量的演化模式类似于光场的菲涅耳衍射。我们最终表明，预期带宽也可以从缀饰场绝热性的演化中推导出来。
