Exploiting plasmon resonances in a composite photonic crystal for polarization-sensitive dichroic filtering

In this communication, we describe the operating principle of a polarization-sensitive dichroic filter consisting of a multilayered photonic structure with an embedded anisotropic composite layer. Our goal is to obtain two separate narrow passbands for two mutually orthogonal polarizations of light. To that effect, we propose to combine a photonic crystal structure with a two-dimensional array of spheroidal metallic nanoparticles. The former consists of two distributed Bragg reflectors surrounding a cavity layer that ensures the existence of narrow transmission peaks (defect modes) in the photonic bandgaps of the structure. The polarization sensitivity of transmittivity and reflectivity is provided by the rectangular array of spheroidal metallic nanoparticles embedded at the center of the cavity layer, in which the excitation of surface plasmon resonances depends on the relative orientations of the anisotropy axes of the nanoparticles and the polarization direction of the incoming light wave.