Fast determination of terahertz polarization azimuth angle based on the core-anti-resonant effect

The azimuth angle of linearly polarized light plays a crucial role in optical mechanism investigations and various applications. However, in the terahertz (THz) band, traditional detection methods suffer from low efficiency or require complex apparatus. In this work, based on the core-anti-resonant reflection (CARR) principle, we propose a polarization-sensitive CARR cavity, namely, a simple 3D-printed tube with an Archimedean spiral structure of the cross section, which links the input linear polarization azimuth angle to the output resonant frequencies. In this way, the spatial polarization angle can be rapidly resolved via the Fourier-transformed THz spectrum from the detected single THz temporal pulse. Therefore, the experimental system configuration is simplified, and more importantly, the detection efficiency has been significantly enhanced.