Circular dichroism in a three-dimensional semiconductor chiral photonic crystal

TL;DR

This paper demonstrates broadband circular dichroism in a 3D semiconductor chiral photonic crystal, achieved through innovative design and fabrication, with results aligning well with simulations.

Contribution

It introduces a novel 3D chiral photonic crystal structure with significant circular dichroism in the telecommunication band, fabricated from GaAs using micro-manipulation.

Findings

Achieved 85% transmittance for right-handed circular polarization at 1300 nm

Demonstrated wide wavelength range of circular dichroism due to high refractive index contrast

Experimental results agree with numerical simulations

Abstract

Circular dichroism covering the telecommunication band is experimentally demonstrated in a semiconductor-based three-dimensional chiral photonic crystal (PhC). We design a rotationally-stacked woodpile PhC structure where neighboring layers are rotated by 60 degrees and three layers construct a single helical unit. The mirror-asymmetric PhC made from GaAs with sub-micron periodicity is fabricated by a micro-manipulation technique. Due to the large contrast of refractive indices between GaAs and air, the experimentally obtained circular dichroism extends over a wide wavelength range, with the transmittance of right-handed circularly polarized incident light being 85% and that of left-handed light being 15% at a wavelength of 1300 nm. The obtained results show good agreement with numerical simulations.