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在太赫兹(THz)波与材料相互作用的研究中, 传统的太赫兹时域光谱(terahertz time-domain spectroscopy, THz-TDS)通常仅探测某一偏振方向的脉冲THz波在与待测样品作用前后的幅值信息和相位信息的变化. 然而对于各向异性、手性特征等材料的检测中, 仅有样品的幅值和相位信息并不能给出样品物质完整的内在结构. 各向异性、手性物质对不同偏振态的脉冲THz是非常敏感的, 要通过THz光谱来反映这些手性物质的构型、构象等信息, 就必须探测脉冲THz波作用样品前后的振幅、相位和偏振态. 本文提出的脉冲THz波全息探测器(pulsed terahertz holographic detector, PTHD)由相互垂直的光电导天线阵元组成, 可以通过一次扫描检测出脉冲THz电场在任意方向的正交分量, 从而可同时检测出脉冲THz波作用样品前后的振幅、相位和偏振态的变化, 故称为脉冲THz波全息探测器. 实验和理论分析都验证了PTHD测量脉冲THz波偏振态的可靠性. 同时, 本文还利用响应矩阵分析了PTHD在0.1—2.2 THz光谱范围内具有良好的对称性.In the study of the interaction of terahertz (THz) wave with material, the traditional THz time-domain spectroscopy (THz-TDS) usually only detects the changes in amplitude and phase information of pulsed THz in a certain polarization direction before and after the interaction with the sample to be tested. However, in the detection of material such as anisotropic material and chiral material, only the amplitude and phase information of the sample cannot give the complete internal structure of the sample material. Anisotropic material and chiral material are very sensitive to pulsed THz of different polarization states. In order to reflect the configurations and conformations of these chiral substances through THz spectrum, it is necessary to detect the amplitude, phase and polarization state of the sample before and after pulse THz waves. The pulsed terahertz holographic detector (PTHD) in this work is composed of photoconductive antenna elements that are perpendicular to each other. The quadrature component of the pulsed THz electric field in any direction can be detected by one-time scanning, so that the changes in amplitude, phase and polarization state before and after the pulsed THz wave acts on the sample can be detected at the same time, so it is called pulsed THz wave holographic detection. Both experiments and theoretical analyses verify the reliability of the PTHD for measuring the polarization state of pulsed THz waves. At the same time, the response matrix is used to analyze that the PTHD has good symmetry in a spectral range of 0.1–2.2 THz.
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Keywords:
- terahertz waves /
- state of polarization /
- response matrix /
- degree of polarization








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