A review of terahertz metamaterial sensors and their applications

Terahertz (THz) waves possess unique characteristics such as high transmission, strong absorption, and low photon energy. THz metamaterial sensors, as label-free and rapid optical sensors, offer significant advantages in detection technology. These sensors enable high-sensitivity, efficient, non-destructive, and low-dose sensing due to the properties of THz waves, the sensitivity of metamaterial devices to changes in the surrounding dielectric environment and the characteristic fingerprint spectrum of biochemical molecules. THz metamaterial sensors hold great potential for applications in biomedicine, non-destructive testing, as well as the food and agricultural sectors. This paper provides a comprehensive review of various detection methods employed by THz metamaterial sensors, which consists of THz refractive index sensors, biometric fingerprint (characteristic absorption peak) sensors and biomass sensors. The study critically discusses different device structures and modulation principles used in these sensors, analyzing their respective strengths weaknesses and development trend. This review represents a broad introduction for beginners.