Terahertz dynamics of complex liquids

传统的太赫兹时域光谱仪（THz-TDS）不适用于复杂液体动力学性质的研究。因此，特别订购的THz-TDS从Tochigi Nikon Corporation购买。由于对于研究快弛豫过程和与合作运动相关的玻色子峰，低于1.0 THz的低能激发是非常重要的。然而，在传统的光谱仪中，使用会聚光束，并且难以精确地确定透射波的相位延迟。在本研究中，使用直径为5 cm的平行光束作为平面波传输样品。利用这台谱仪，我们系统地研究了（1）乙醇水溶液，（2）多元醇等低温保护剂，（3）碱金属硼酸盐玻璃等三种物质。在0.1 THz ~ 3.0 THz范围内测定了复介电常数的真实的和虚部。这些结果已被分析，考虑非德拜弛豫和振动态的中程秩序。

The commercially available conventional Terahertz time domain spectrometer (THz-TDS) is not suitable for the studies of dynamical properties of complex liquids. Therefore, the specially ordered THz-TDS was purchased from Tochigi Nikon Corporation. Since for the study of the fast relaxation process and boson peaks related to cooperative motion, the low energy excitation below 1.0 THz is very important. However, the convergent beam is used in the conventional spectrometer and the accurate determination of the phase delay of the transmitted wave is difficult. In the present investigation, the parallel beam with 5 cm diameter is used to transmit a sample as plane waves. By using this spectrometer we have systematically studied the following three kinds of materials, (l) alcohol aqueous solution, (2) cryo-protectant materials such as poly alcohols, (3) alkali borate glasses. The real and imaginary parts of complex dielectric constants have been determined from 0.1 THz to 3.0 THz. These results have been analyzed by considering non-Debye relaxation and vibrational states of medium-range order.