Voltage-induced defect mode interaction in a one-dimensional photonic crystal with a twisted-nematic defect layer

TL;DR

This paper investigates how voltage can control defect modes in a one-dimensional photonic crystal with a twisted-nematic liquid crystal layer, revealing complex polarization interactions and avoided crossing phenomena.

Contribution

It provides a combined experimental and theoretical analysis of voltage-induced defect mode interactions in a tunable 1D photonic crystal with a twisted-nematic defect layer, including polarization effects.

Findings

Defect modes exhibit frequency shifts under applied voltage.

Polarized defect modes can interact and show avoided crossing.

The defect modes can have complex elliptic polarization structures.

Abstract

Defect modes are investigated in a band gap of an electrically tunable one-dimensional photonic crystal infiltrated with a twisted-nematic liquid crystal (1D PC/TN). Their frequency shift and interference under applied voltage are studied both experimentally and theoretically. We deal with the case where the defect layer thickness is much larger than the wavelength (Mauguin condition). It is shown theoretically that the defect modes could have a complex structure with the elliptic polarization. Two series of polarized modes interact with each other and exhibit an avoided crossing phenomenon in the case of opposite parity.