# Realizing polarization conversion and unidirectional transmission by using a uniaxial crystal plate

## TL;DR

This paper demonstrates how a thin uniaxial crystal plate can be used to manipulate polarization states of electromagnetic waves, enabling complete polarization conversion and unidirectional transmission through simple device design.

## Contribution

It introduces a method to achieve polarization conversion and unidirectional transmission using a uniaxial crystal plate with controlled thickness and orientation, explaining experimental results with metamaterials.

## Key findings

- Complete polarization conversion between TE and TM waves achieved.
- Off-diagonal permittivity element is crucial for polarization conversion.
- Proposed device enables unidirectional transmission via polarization control.

## Abstract

We show that polarization states of electromagnetic waves can be manipulated easily using a single thin uniaxial crystal plate. By performing a rotational transformation of the coordinates and controlling the thickness of the plate, we can achieve a complete polarization conversion between TE wave and TM wave in a spectral band. We show that the off-diagonal element of the permittivity is the key for polarization conversion. Our analysis can explain clearly the results found in experiments with metamaterials. Finally, we propose a simple device to realize unidirectional transmission based on polarization conversion and excitation of surface plasmon polaritons.

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Source: https://tomesphere.com/paper/1703.00554