Electrically controlled lateral shift of the reflected optical beams from a nanocomposite structurally chiral medium

Abstract

In this paper, we theoretically investigate the influence of an external electric field on the lateral shifts of the reflected right-handed circularly polarized beam from a nanocomposite slab at the edge wavelengths of the photonic bandgaps of the structure. The nanocomposite slab is a non-dissipative dielectric chiral material with the randomly dispersed silver nanoparticles inside it. We show that the increase of the applied electric field results in the decrease of the positive lateral shift at the lower edge of the Bragg gap, while the negative lateral shift at the upper edge of the Bragg gap increases by increasing the applied field. Moreover, we show that the impact of the applied voltage is more noticeable at larger incident angles for both the lower and upper edge wavelengths of the Bragg gap. Also, it is shown that the tilt angle of the chiral structure and the slab thickness have considerable effects on the controlling behavior of the externally applied voltage. Finally, we investigate the effect of the filling fraction of nanoparticles and show that the inclusion of the nanoparticles can change the influence of the applied voltage on the lateral shift of the reflected beams.