论文标题
Terahertz离子Kerr效应：对绝缘体中非线性光学响应的两次贡献
Terahertz ionic Kerr effect: Two-phonon contribution to the nonlinear optical response in insulators
论文作者
论文摘要
Thz Kerr效应通过驱动系统的拉曼活性激发的强烈THZ脉冲来测量否则各向同性材料中引起的双折射。在这里，我们提供了由于红外活性晶格振动引起的绝缘SRTIO3的相当大的KERR响应的实验证据。这种名为Ionic Kerr效应的信号与多个声子的同时激发有关。多亏了双折射的时间，极化和温度依赖性的理论模型，我们可以将离子Kerr效应与非谐振电子激发相关，从而提供了一种可调节的可调机制，以通过Infra-Red活性语音调节超级时间尺度上的超级尺度上的折射率。
The THz Kerr effect measures the birefringence induced in an otherwise isotropic material by a strong THz pulse driving the Raman-active excitations of the systems. Here we provide experimental evidence of a sizable Kerr response in insulating SrTiO3 due to infrared-active lattice vibrations. Such a signal, named ionic Kerr effect, is associated with the simultaneous excitation of multiple phonons. Thanks to a theoretical modeling of the time, polarization and temperature dependence of the birefringence we can disentangle the ionic Kerr effect from the off-resonant electronic excitations, providing an alternative tunable mechanism to modulate the refractive index on ultrashort time-scales via infra-red active phonons.
