Tunable physical effects in Bi-mica hyperbolic structures

Recent years, the need to create tunable THz devices emerged due to rapid development of THz photonics. As a rule, such devices are based on semiconductors and phase change materials, and the use of hyperbolic media based on these materials is a promising approach to realize terahertz wave near-field control. In this work, the dispersion of complex effective permittivity tensor of a layered structure consisting of 40 nm, 70 nm and 120 nm semimetallic Bi films on a top of 21 μm mica dielectric substrate, calculated on the basis of THz time-domain spectroscopy method, is used to theoretically estimate such effects as Purcell enhancement, Van Hove singularity, and Compton effect. The influence of continuous-wave optical pumping onto the optical properties of Bi-based hyperbolic medium and related effects is also studied in this work. The studied effects may be used in THz radiation enhancement, thermoelectric engineering and thermophotovoltaics, optical and electronic detection, molecular sensing, and even in development of spasers. The obtained results prove the possibility of application of Bi-mica composite in a development of fast-acting terahertz hyperbolic materials which are easy to produce due to their simple structure. •The optical control of the Purcell factor in Bi-film was studied for the first time.•The optical pumping effect on Van Hove and Compton effects in Bi-film was studied.•The Purcell factor enhancement in Bi-film was theoretically investigated.•The slow light mode presence,the change in THz wave and electrons pulse were studied.•The ability of using Bi with optically controlled parameters in photonics is shown.