Dual-channel dynamic modulation for polarization-dependent absorption by gating ultrathin TiN films in the near-infrared region

Abstract

Ultrathin titanium nitride (TiN) is a novel material flatform for constructing active metasurfaces in the near-infrared region (NIR). In this paper, we numerically achieved the dual-channel dynamic modulation for polarization-dependent absorption by adjusting incident angles and gating ultrathin TiN films. To enhance the active modulation effect of ultrathin TiN film, the “卍” shaped gold resonator is integrated with ultrathin TiN film for constructing a metasurface Salisbury screen (MSS). By electrical reducing TiN carrier concentration by 12%, the absorption peak of TE wave blueshifts 100 nm. The magnitude and the frequency of the polarization-dependent absorption are independently tuned by changing incident angles or the carrier concentration in TiN film. The ultrathin TiN film based polarization-dependent metasurface enabling versatile dual-channel modulation has great potentials in the applications of optical communication, information encryption, real-time imaging etc.