Magnetically tunable metasurface comprising InAs and InSb pixels for absorbing terahertz radiation

A magnetically tunable metasurface comprising meta-atoms with InSb-patched, InAs-patched, and unpatched pixels was simulated using commercial software to maximize the absorption of normally incident radiation in the terahertz spectral regime, with the patches decorating the illuminated face of a gold-backed polyimide substrate. Maximum absorptance of 0.99 and minimum absorptance of 0.95 can be obtained in 0.14–0.23-THz-wide bands in the 2–4-THz spectral regime, with an average tuning rate of 0.3 THz T⁻¹ and 0.24-THz dynamic range when the controlling magnetostatic field is aligned parallel to the incident electric field. The use of both InSb and InAs patches is much superior to the use of patches of only one of those materials. The design can be adapted for neighboring spectral regimes by exploiting the scale invariance of the Maxwell equations.