Real-time observation of phonon-polariton dynamics in ferroelectric LiNbO3 in time-frequency space
Real-time observation of phonon-polariton dynamics in ferroelectric LiNbO3 in time-frequency space
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DOI：
10.1063/1.4928480
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发表时间：
2015-08-10
影响因子：
4
通讯作者：
Takeda, Jun
中科院分区：
文献类型：
--
作者：
Ikegaya, Yuki;Sakaibara, Hiroyuki;Takeda, Jun
我们演示了使用采用阶梯镜的单次光谱装置对铁电 LiNbO3 中声子极化子传播的实时观察。阶梯镜为探测脉冲提供空间编码的时间延迟；因此，可以单次检测材料的超快瞬态行为。使用光学克尔门装置，通过脉冲受激拉曼散射过程同时诱导向前和向后传播的E模声子极化激元，随后，使用外差检测将它们的动态映射到时频空间。两个声子极化子出现在中心探测波长的相对两侧，并在普通和异常探测光的照射下对称成像。通过考虑最低 E 模式声子极化与低频弛豫模式的耦合，不仅揭示了声子极化子色散，而且还揭示并定量评估了阻尼率的波矢量依赖性。 (C) 2015 AIP 出版有限责任公司。
We demonstrate the real-time observation of phonon-polariton propagation in ferroelectric LiNbO3 using a single-shot spectroscopic setup that employs an echelon mirror. The echelon mirror provides a spatially encoded time delay for the probe pulse; therefore, the ultrafast transient behavior of materials can be detected on a single-shot basis. Using optical Kerr gate apparatus, forward and backward propagating E-mode phonon-polaritons were simultaneously induced via an impulsive stimulated Raman scattering process, and subsequently, their dynamics were readily mapped in time-frequency space using heterodyne detection. The two phonon-polaritons appeared on opposite sides of the central probe wavelength and were symmetrically imaged against the ordinary and extraordinary probe lights. By taking into account coupling of the lowest E-mode phonon-polariton to a low-frequency relaxational mode, not only the phonon-polariton dispersion but also the wavevector dependence of the damping rate was unveiled and quantitatively evaluated. (C) 2015 AIP Publishing LLC.