Application of metasurface-based low-pass filters for improving THz-TDS characteristics

Abstract

Abstract We propose an approach to improve the technical characteristics of terahertz time-domain spectrometers at low-frequency measurements. The approach is based on applying low-pass THz filters to narrow the frequency band of the THz signal that allows increasing the sampling interval in accordance with the Nyquist–Shannon theorem. This concept was verified by studying the transmission spectra of low-frequency band-pass THz filters centered at 156 and 376 GHz. We confirm that the high-quality low-pass filters can improve accuracy of THz measurements and significantly reduce data acquisition time. The reduction up to 12 times was experimentally demonstrated in our case.