Laboratoire de Chimie Physique, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Bâtiment 201 P2, 91405 Orsay, France.
J Chem Phys. 2018 Apr 7;148(13):134701. doi: 10.1063/1.5021553.
We experimentally determine the effective nonlinear second-order susceptibility of gold over the visible spectral range. To reach that goal, we probe by vibrational two-color sum-frequency generation spectroscopy the methyl stretching region of a dodecanethiol self-assembled monolayer adsorbed on a gold film. The sum-frequency generation spectra show a remarkable shape reversal when the visible probe wavelength is tuned from 435 to 705 nm. After correcting from Fresnel effects, the methyl stretching vibrations serve as an internal reference, allowing to extract the dispersion of the absolute phase and relative amplitude of the effective nonlinear optical response of gold in the visible range.
我们通过实验确定了金在可见光谱范围内的有效二阶非线性极化率。为了实现这一目标，我们通过振动双色和频光谱法探测了吸附在金膜上的十二硫醇自组装单层的甲基伸缩振动区域。当可见探测波长从 435nm 调谐到 705nm 时，和频光谱显示出显著的形状反转。在消除菲涅耳效应的影响后，甲基伸缩振动作为内部参考，可以提取金在可见范围内有效非线性光学响应的绝对相位和相对振幅的色散。
