Wavefront engineering with optimally loaded absorbing metamirrors

Abstract

Modifying the wavefront of electromagnetic fields is one of the most significant operations in a variety of photonic components from spatial wave modulators and optical deflectors to focusing lenses and reflectarray nanoantennas. Metamirrors comprising dielectric and plasmonic layers back-to-back are found to serve well such a purpose of wavefront transformation for reflected waves with use of tiny scatterers placed at positions of enhanced field and by exploiting the absorbing mechanism of these bilayers. Even though the efficiency of the configurations is not high due to the presence of losses, the tailoring of the reflective wave pattern is successful given the simplicity of the considered setups. In particular, numerous optimal designs that anomalously reflect the incoming plane waves or convert them into cylindrical ones have been determined by trying and testing every combination from a large set of available media. Thus, extra degrees of freedom are provided in modeling such modules that are vital for several wavefront engineering applications.