论文标题
在Thz频率下的晶体石英中极大的非线性响应
Extremely large nonlinear response in crystalline quartz at THz frequencies
论文作者
论文摘要
我们报告了Terahertz（THZ）频率区域中THZ时域光谱（THZ-TDS）中晶体石英中非常强的非线性反应的第一次实验性观察。提出了理论建模，并预测Kerr系数N2等于5.17*10^-14 m^2 W^-1。测量数据的时间域分析表明，随着THZ峰幅度的增加，脉冲在样品中的时间延迟较大。随着THZ振幅增加到高于110 kV cm^-1的值，延迟的生长速率降低，表明饱和过程。通过频率响应分析计算得出的非线性折射率的值估计为10^-13 m^2 W^-1，这比可见区域中固体的非线性折射率的典型值大几个数量级。此外，测量了10^-30 m^4 V^-4的五阶敏感性。
We report on the first experimental observation of a very strong nonlinear response in crystalline quartz in the terahertz (THz) frequency region through THz time-domain spectroscopy (THz-TDS). Theoretical modelling is presented and predicts a Kerr coefficient n2 equal to 5.17*10^-14 m^2 W^-1. The time-domain analysis of the measured data shows that with increasing of the THz peak amplitude, the pulse experiences a larger time delay in the sample. As the THz amplitude increases to values higher than 110 kV cm^-1, the growth rate of the delay decreases, indicating a saturation process. The value of the nonlinear refractive index calculated through the frequency response analysis is estimated to be on the order of 10^-13 m^2 W^-1, which is several orders of magnitude larger than typical values of the nonlinear refractive index of solids in the visible region. Furthermore, a negative fifth-order susceptibility on the order of 10^-30 m^4 V^-4 is measured.
