Polarization-selective window-mirror effect in inductive gold grids

A thin gold film perforated with an array of subwavelength holes is known to exhibit extraordinary transmission at normal incidence, irrespective of the state of polarization of illumination. We report that, at slightly non-normal incidence (∼8°), a properly designed inductive metal nanogrid may act as a window (with enhanced transmittance of 70%) or a mirror (with zero transmittance and enhanced reflectance) at a given wavelength, depending on the state of polarization of incident light. Experimental and numerical investigations reveal the role of surface plasmons as the underlying physical mechanism of this effect.