# Polarization exchange of optical eigenmode pair in twisted-nematic Fabry-P\'erot resonator

## TL;DR

This paper experimentally demonstrates polarization exchange in a twisted-nematic Fabry-Pérot resonator, showing voltage-controlled polarization rotation and potential for spectral-selective linear polarization filtering.

## Contribution

It provides the first experimental confirmation of polarization exchange effects in twisted-nematic Fabry-Pérot resonators under various conditions.

## Key findings

- Polarization of output light is linear at transmission peaks.
- Polarization deflects from nematic director, exchanging directions.
- Voltage untwisting rotates the polarization plane.

## Abstract

The polarization exchange effect in a twisted-nematic Fabry-P\'erot resonator is experimentally confirmed in the regimes of both uniform and electric-field-deformed twisted structures. The polarization of output light in the transmission peaks is shown to be linear rather than elliptical. The polarization deflection from the nematic director grows from $0^\circ$ to $90^\circ$ angle and exchanges the longitudinal and transverse directions. Untwisting of a nematic by a voltage leads to the rotation of the polarization plane of light passing through the resonator. The polarization exchange effect allows using the investigated resonator as a spectral-selective linear polarizer with the voltage-controlled rotation of the polarization plane.