Eradicating backscattering through circular conversion dichroism in optical regime

Abstract

Circular dichroism (CD) and asymmetric transmission (AT) are two outstanding chiroptical effects, which can be produced by planar chiral devices due to their distinct response to oppositely handed input light. The chiroptical effects have so far been used in realization of different applications including chiral imaging and sensing. This research realizes CD in the optical regime to attain AT for an optical wavelength regime by employing a supercell of hydrogenated amorphous Silicon nano-bars. The supercell is made of four achiral nanofins which are engineered in such a way that they exhibit a notable CD and AT. The design successfully achieves a CD of 55% and that of AT of 58% at the operating wavelength of 633 nm. The supercell absorbs the right circularly polarized light and transmits left circularly polarized light, thus behaving as a perfect circular polarization wave isolator i.e. the presented design can completely eradicate backscattering by minimizing reflectance.