Angular dependence in light propagation through silver material based ultra-compact photonic crystal

Abstract

This paper presents the light propagation efficiency in ultra-compact photonic crystal (UCPC) of silver (Ag) material filled with square air background in periodical lattice structure. In different angles of incidence θ, we extremely investigate the effect exerted by the angular selective in modifying the optical properties of reflection, transmission and absorption spectra. To this aim, we applied the finite-differential time-domain (FDTD) simulations under Lumerical FDTD Solutions; the broadband fixed angle source technique (BFAST) which is based on the split-field FDTD algorithm was selected for the plane wave source injection. This allows to standardize all the interested wavelengths by having the same incident angle and therefore avoided the wavelength dependence issues. It revealed that the increase of reflection is satisfied by incidence angle θ<π/4 rad and wavelength λ > 550 nm. In this spectral range, similar trends of reflection are seen in lower angles of incidence. The transmission is approximately 50% far to the unity due to the high reflection backed and describes divergent features to those of reflection. Addition in layers avoids high reflection, optimizes the field transmitted and enhances significantly the absorption over the Ag UCPC. The optimization of transmission is either occurs with increase in angle of incidence. Consequently, these characteristics opening the way to ensure that such structure may act as filter in electromagnetic light propagation with respect to the position of the angle of incidence and the size of the thickness.