Study of electron-phonon dynamics in coherent phonon fields by using a spectral-resolved pump-probe method

我们用波长分辨的泵浦-探测方法研究了相干声子的性质，以阐明相干声子场中的电子-晶格动力学。在透射区对半导体的激发下，声子幅度的探测能量依赖关系在与探测脉冲中心波长相差一个声子频率的能量处有两个峰值。另一方面，不透明区域的振幅在能量平移约两倍于声子频率时出现两个峰值。我们在动态介电响应理论的基础上讨论了探测能量的依赖关系。动态介电响应理论表明，在透明和不透明区域观察到的探测-能量依赖关系可以通过考虑由相干声子场调制的电子复介电函数来解释。

We have investigated the properties of coherent phonons using a wavelength-resolved pump-probe method, to clarify the electron-lattice dynamics in coherent phonon fields. At the excitation in the transparent region to CdTe semiconductors, the detection-energy dependence of the phonon amplitude has two peaks at the energy shifted by one-phonon frequency of CdTe from the center wavelength of the probe pulses. On the other hand, the amplitude in the opaque region shows two peaks at the energy shifted by about two times the phonon frequency. We have discussed the detection-energy dependence on the basis of the dynamical dielectric response theory. The dynamical dielectric response theory demonstrates that the detection-energy dependence observed in the transparent and opaque regions can be explained by taking into account the electronic complex dielectric function modulated by coherent phonon fields.