State-of-the-Art Emerging Materials under a Terahertz Emission Spotlight

The generation and manipulation of photoinduced transient currents, as well as characterization of the emission of resultant electromagnetic waves, are crucial for the design and coherent operation of advanced optoelectronic devices. An ultrafast optical pulse-driven transient photocurrent lasts for picosecond time scale bursts as a terahertz (THz) emission. The emitted radiation, permitted by the intrinsic structural properties of materials, is remarkably enriched with information on associated ultrafast transients and can potentially explore microscopic insights into fascinating nonlinear dynamical characteristics. This review aims to understand terahertz (THz) emission and the underlying ultrafast photophysics in contemporary matter systems. Since THz emission is the manifestation of photocurrents and induced dynamic polarization that sustain a picosecond time scale, it offers a noncontact and noninvasive platform for studying such ultrafast phenomena.