# Helicity amplitudes, polarization of EM waves and Stokes parameters

## TL;DR

This paper demonstrates that helicity amplitudes effectively describe electromagnetic field properties, including polarization and Stokes parameters, bridging classical and quantum theories with a concise, relativistically meaningful framework.

## Contribution

It introduces the use of helicity amplitudes as a unified, relativistically consistent method to analyze electromagnetic polarization and related concepts.

## Key findings

- Helicity amplitudes encode polarization and Stokes parameters.
- They provide a relativistic description of electromagnetic properties.
- The approach bridges classical and quantum electromagnetic theory.

## Abstract

It is shown that the helicity amplitudes can be used to describe and analyze the properties of the electromagnetic field in classical and in quantum theory. On the one hand they embody the relativistic content of electromagnetic theory. On the other hand they give a concise description of such experimentally important notions as polarization, the Stokes parameters and the Poincar\'e sphere.