Ultra-Wide Dual-Band Fingerprint Spectral Sensing

Metasurface devices for biological sensing have been used to design a variety of terahertz (THz) biosensors. However, due to the fixed nature of the metasurface structure, these sensor devices are limited to tuning at a single frequency point or in a narrow range, making it difficult to achieve a wide range of frequency modulation. In this paper, a novel design concept for optically controlled frequency modulation is proposed to enable fingerprint spectral sensing over a very large resonant frequency shift range of 0.86 to 1.81 THz. At the same time, transitions on the order of picoseconds are achieved based on the excitation and relaxation times of the carriers. It provides an example for large-scale applications of tunable devices and ultra-wideband biosensing.