Applications of THz Technology in Materials Characterization, Sensing, Communication, and Biomedical Fields

Terahertz (THz) technology has emerged as a versatile platform enabling advancements across materials characterization, sensing, wireless communication, and biomedical diagnostics. This review provides a unified perspective on these application domains by highlighting the central role of terahertz time-domain spectroscopy (THz-TDS) as a fundamental tool for probing material electrodynamics. THz-TDS enables simultaneous measurement of amplitude and phase of the electric field, allowing contact-free direct extraction of complex permittivity, conductivity and other dielectric properties. Building on this capability, the review connects material-level properties to device and system-level functionalities, including metamaterial-based sensors, graphene-enabled reconfigurable intelligent surfaces (RISs), and beam-steering architectures relevant to 6G and beyond communication systems. Furthermore, the potential of THz techniques in biomedical applications is discussed in detail, particularly for non-invasive tumor detection through dielectric contrast mapping and imaging-based reconstruction methods. By integrating developments across these domains, this review presents THz-TDS as a unifying framework that links materials physics to emerging technologies in sensing, communication, and healthcare, offering insights into future directions for THz research and applications. The principal contribution of this review is to present a cross-domain framework that relates THz field measurements and extracted material electrodynamics to sensing, reconfigurable wavefront control, communication technologies, and biomaterials characterization.