Terahertz superlattice modes in moiré metasurface composed of twisted square and hexagonal lattices

Abstract

Abstract We numerically investigate the terahertz superlattice mode in a moiré metasurface containing fringe of squares and hexagonal structures. The edge of moiré fringes works as a route of uni-directional surface current driven by the incident terahertz polarization. As such, each lateral edge of moiré fringe works as dipole oscillator, which collectively resonate in-phase leading to the lattice mode. A large twisted angle leads to a relatively high resonance frequency, as well as, a high quality factor. Our finding manifest a new method to tuning the lattice mode by terahertz twistronics.