Reflection band gap for a transversely stretched composite cholesteric elastomer

Abstract

We have studied the conduction of electromagnetic waves, impinging normally in a composite cholesteric elastomer slab, doped with metallic inclusions, aleatory distributed in the structure. We performed a theoretical and numerical model, which allows us to obtain the reflection and transmission spectra, when the system is under the action of mechanical forces in a transverse direction with respect to the cholesteric axis. We have found that by stretching the elastomer slab transversely after the critical value of stretching in which the helical structure gets unwound, it transform from a discriminatory circular filter to a polarization-independent device. Intervals of conversion, from right to left circularly-polarized waves in the reflection spectra, are alternated with regions of resembling transmission of both circularly polarized waves. The spectra of the pure cholesteric elastomer can be modulated specially nearby the metallic resonance where the transmittances are greatly damped and reflection is considerably increased.