Full Stokes polarimetry using Dual-Frequency Liquid Crystals

TL;DR

This paper demonstrates a novel application of dual-frequency liquid crystals in full Stokes polarimetry, utilizing their frequency-dependent switching properties to develop a polarization modulator capable of broadband operation from 600 to 900 nm.

Contribution

It introduces a new polarization modulation technique using DFLCs combined with static retarders for full Stokes polarimetry across a broad wavelength range.

Findings

Successful design of a DFLC-based polarization modulator

Optimization of modulator angles for balanced Stokes parameter measurement

Potential for polychromatic operation in the 600-900 nm range

Abstract

In a dual-frequency liquid crystal (DFLC), when the frequency of the applied voltage is more than a critical value ($f_c$), the dielectric anisotropy of the material changes from positive to negative. This causes the director to switch its orientation from parallel to the field (for $f < f_c$), to perpendicular to it ($f > f_c$). Hence DFLC can be used in modulating the light by switching the frequency of an externally applied voltage. We present in this work about application of DFLCs in full Stokes polarimetery. A polarization modulator has been worked out based on two DFLCs and two static retarders. The combination of DFLCs' switching and static retarders are chosen such that more or less equal weightage is given to all the Stokes parameters. Initial results on the optimization of position angles of the modulators are presented towards the goal of achieving polychromatic modulator in the wavelength range 600-900 nm.