# Experimental characterization of quantum polarization of three-photon states

## TL;DR

This paper experimentally explores the quantum polarization properties of various three-photon states, revealing unique features like maximum sum-uncertainty and hidden polarizations across different state classes.

## Contribution

It introduces a classification of three-photon quantum states based on polarization symmetry and experimentally characterizes their quantum polarization features.

## Key findings

- Identification of six classes of three-photon states based on polarization symmetry
- Observation of maximum sum-uncertainty in certain states
- Detection of hidden polarization phenomena

## Abstract

We experimentally investigate various quantum polarization features of three-photon quantum states, including product and entangled states with varying purity. The three-photon quantum states are categorized into six classes based on the rotation symmetry of mean, variance, and skewness of the polarization distribution. The representative three-photon quantum states in each category is prepared from double-pair emission from pulsed spontaneous parametric down-conversion and quantum interferometry. We demonstrate that the three-photon quantum states show interesting quantum polarization properties, such as, maximum sum-uncertainty and hidden polarizations.