Terahertz radiation induced by coherent phonon generation via impulsive stimulated Raman scattering in paratellurite
Terahertz radiation induced by coherent phonon generation via impulsive stimulated Raman scattering in paratellurite
复制标题
DOI：
10.1103/physreva.90.033842
复制
发表时间：
2014-07
影响因子：
2.9
通讯作者：
M. Sotome;N. Kida;R. Takeda;H. Okamoto
中科院分区：
文献类型：
--
作者：
M. Sotome;N. Kida;R. Takeda;H. Okamoto
本文报道了用飞秒激光脉冲在室温下观察到非中心对称的绝缘氧化物--仲亚硫酸盐(α-TeO$2)中的太赫兹辐射。在太赫兹辐射的功率谱中，在3太赫兹以下出现周期为0.25太赫兹的强度条纹图。考虑到太赫兹辐射在较差的相位匹配条件下的有效产生长度，它可以被重现。此外，在辐射的太赫兹波中还出现了一个时间振荡分量，其频率为3.71太赫兹，这与拉曼主动纵向光学(LO)$E$模的中心频率是一致的。在全面的偏振光学和拉曼光谱研究的基础上，我们从脉冲受激拉曼散射产生相干声子的角度解释了时间振荡分量的产生机制。
We report on the observation of terahertz radiation in a non-centrosymmetric insulating oxide, paratellurite ($\alpha$-TeO$_2$) by irradiation of a femtosecond laser pulse at room temperature. In the power spectrum of the terahertz radiation, an intensity fringe pattern with a period of $\sim$ 0.25 THz shows up below 3 THz. It can be reproduced by taking into account the effective generation length for the terahertz radiation with a poor phase-matching condition. In addition, a temporal oscillation component appears in the radiated terahertz wave with a frequency of $\sim$ 3.71 THz, which is in good agreement with the center frequency of the Raman active longitudinal optical (LO) $E$ mode. On the basis of comprehensive polarized optical and Raman spectroscopic studies, we explain the generation mechanism of the temporal oscillation component in terms of the coherent phonon generation via impulsive stimulated Raman scattering.