Use of dielectric nanoparticles for designing high-reflection coatings and dielectric mirrors

In this contribution, we investigate the use of high-index nanoparticles as a possible solution for realizing ultra-thin dielectric mirrors working at a desired frequency of the optical spectrum. First, exploiting the Mie theory for spherical scatterers, we will show that it is possible engineering the optical response of a high-index nanoparticle and maximizing the difference between its forward and backward scattering. Then, we will show that, when such optimized nanoparticles are arranged in a proper lattice, they behave as perfect optical mirrors with 20 % fractional bandwidth. A possible realistic implementation, based on crystalline silicon, is also proposed and checked with full-wave simulations.