# Scattering of Poincare beams: polarization speckles

## TL;DR

This paper explores how scattering Poincaré beams through a ground glass plate creates polarization speckles, analyzing their polarization properties and how speckle size varies with the beam's index.

## Contribution

It demonstrates the generation and analysis of polarization speckles from Poincaré beams and reveals how speckle size depends on the beam's vector index.

## Key findings

- Scalar speckle size is independent of the vector beam index.
- Polarization speckle size decreases with increasing vector beam index.
- Spatial variation of polarization is characterized using Stokes parameters.

## Abstract

Polarization speckle is a fine granular light pattern having spatially varying random polarization profile. We generate these speckle patterns by using the scattering of Poincar\'e beams, a special class of vector vortex beams, through a ground glass plate. Here, the Poincar\'e beams are generated using a polarization sensitive spatial light modulator displaying an on-axis hologram corresponding to an optical vortex phase profile. The different inhomogeneities of the rough surface experience different polarizations, which control the ability for scattered waves to interfere at the detection plane and causes a spatially varying polarization profile. We experimentally determined the spatial variation of local degree of polarization and orientation of the polarization ellipse for these speckle patterns from the Stokes analysis. We also determined the size of scalar speckles using the auto-correlation function of Stokes parameter S0 and the size of polarization speckles using the sum of auto-correlation functions of remaining three Stokes parameters. We found that the scalar speckle size is independent of index of the vector beam but the size of polarization speckles decreases with the increase in index of the vector beam.