Measuring Optical Activity with Unpolarised Light: Ghost Polarimetry

TL;DR

This paper introduces ghost polarimetry, a novel method using entangled photons to measure optical activity with unpolarised light, enabling low-light and less perturbative analysis of chiral samples.

Contribution

It presents a new technique that measures optical activity without requiring polarised light, expanding capabilities for delicate or sensitive samples.

Findings

Enables measurement of optical activity with unpolarised light.

Reduces perturbation of samples during measurement.

Allows low-light optical activity analysis.

Abstract

Quantifying the optical chirality of a sample requires the precise measurement of the rotation of the plane of linear polarisation of the transmitted light. Central to this notion is that the sample needs to be exposed to light of a defined polarisation state. We show that by using a polarisation-entangled photon source we can measure optical activity whilst illuminating a sample with unpolarised light. This not only allows for low light measurement of optical activity but also allows for the analysis of samples that would otherwise be perturbed if subject to polarised light.