Dual-band terahertz refractive index sensor based on chiral metasurface

Metasurface sensor has become one of the emerging technologies in the field of micro and nano photonics in recent years. Chiral metasurface has unique advantages in chiral molecular detection and biosensing. This paper proposes a terahertz refractive index sensor based on chiral metasurface, which consists of a top layer of pattern, a dielectric layer and a bottom layer of metal reflection layer. The simulation results show that the maximum difference of circular dichroism spectra reaches 0.8 and −0.76 at 6.51 THz and 6.99 THz, respectively. The sensitivities of refractive index reach −1.04 THz RIU −1 and −1.093 THz RIU −1 respectively at two peaks. Therefore, the proposed metasurface sensor using chiral sensing method has the advantages of high sensitivity and wide range of refractive index detection. The sensor can be extended to industrial fields such as terahertz biological and chemical sensing.