Active terahertz modulation via functional materials: Recent advances and applications

Abstract

The terahertz electromagnetic wave band has recently attracted more attention, is a highly anticipated technology, expected to play an important role in communication, healthcare, environment, and security. With its low photon-energy characteristics, the application of terahertz, which can non-destructively inspect the physical and optical properties of materials. From this point of view, the key is to ensure the free control and versatility of devices operating in this band. To do this, many recent research introduced modulation of the physical properties of materials or combine appropriate structures. We will examine in detail the studies that regulate the physical properties of the material itself by external stimuli such as optical, electrical, or thermal excitation, and the fundamental governing mechanisms by which optical constants can be controlled. This review highlights the potential of the terahertz devices for high-sensitivity sensing technology and its future applications in various fields, along with the challenges of the latest technology.