Encoding and display with stereo split-ring resonator arrays.

In this Letter, we report on encoding and display based on stereo standing U-shaped resonator (SUSR) arrays. The SUSR serves as a perfect absorber at a structure-dependent frequency when the polarization of incident light is parallel to the bottom rim of the SUSR. When the incidence polarization is rotated for 90° (perpendicular to the bottom rim of the SUSR), the SUSR turns to a perfect reflector at broadband frequencies. Further, the resonant frequency sensitively depends on the height of the arms of the SUSR. By introducing SUSRs with different arm heights, a resonant absorption state may occur at different frequencies. By defining the resonant absorption state as "dark" and the reflection state as "bright," we can encode and display binary patterns. Beside, when the SUSR rotates with the direction of the standing arms as axis, a different reflectivity, hence, a different shade will be generated. In this way, we may realize a grayscale display. Experimentally, we demonstrate that this encoding and display scheme indeed works.