Kawada Yoichi, Yoshioka Katsumasa, Arashida Yusuke, Katayama Ikufumi, Takeda Jun, Takahashi Hironori
Opt Express. 2018 Nov 12;26(23):30420-30434. doi: 10.1364/OE.26.030420.
Here we demonstrate simultaneous measurements of the complex transmittance and birefringence using left- and right-handed circularly polarized terahertz (THz) pulses. We change the polarization of the THz pulses periodically by modulating the polarization of the pump pulses directed onto a ZnTe (111) crystal, and we convert linear to circular polarization using a broadband THz quarter-wave retarder. By integrating the alternating-emission system with the polarization-sensitive terahertz time-domain spectrometer, we are able to obtain the electric-field vector of the transmitted terahertz pulses for both the left- and right-handed circular polarizations. Utilizing this technique, we are able to measure simultaneously the frequency-dependent complex refractive indices (real and imaginary parts) and the orientations of the slow and fast axes of birefringent materials, a quartz disc and a barium borate crystal, in a single temporal sweep.
在这里，我们展示了使用左旋和右旋圆偏振太赫兹（THz）脉冲同时测量复透射率和双折射。我们通过调制入射到ZnTe（111）晶体上的泵浦脉冲的偏振来周期性地改变太赫兹脉冲的偏振，并使用宽带太赫兹四分之一波延迟器将线偏振转换为圆偏振。通过将交替发射系统与偏振敏感太赫兹时域光谱仪集成，我们能够获得左旋和右旋圆偏振透射太赫兹脉冲的电场矢量。利用这项技术，我们能够在单次时间扫描中同时测量双折射材料（石英盘和硼酸钡晶体）的频率相关复折射率（实部和虚部）以及快慢轴的方向。
