Effects of pressure and thickness on the transmittance spectrum in a PS/PMMA photonic crystal

Abstract

We can calculate the transmittance spectrum of a one-dimensional photonic crystal with alternating polystyrene (PS) and poly (methyl methacrylate) (PMMA) layers using the transfer matrix method. In this work, we have considered the dependence of the dielectric constant of polymers on the applied hydrostatic pressure. We observed that the spectrum exhibited a shift toward regions of high frequencies because of a decrease in the dielectric constant of the materials with an increase in the applied pressure while maintaining a constant layer thickness. Further, the spectrum was observed to shift to short frequencies when the pressure was maintained constant and the layer thickness was increased. In addition, we introduced a PMMA defective layer into the structure. In the defect mode, we observed a gap inside, which changed its position at large frequencies with an increase in the fixed layer thickness values. Further, the defect mode is tuned to short frequencies by varying the layer thickness for a given hydrostatic pressure value.