A note on optical activity and extrinsic chirality

TL;DR

This paper clarifies misconceptions about measuring optical activity, emphasizing that simply illuminating materials with circularly polarized light and analyzing differential responses can be misleading, especially regarding extrinsic chirality.

Contribution

It challenges the common assumption that optical activity can be measured by differential response to circular polarization, clarifying the distinction from extrinsic chirality.

Findings

Illumination with circularly polarized light does not reliably measure optical activity.

Misinterpretations have led to incorrect associations between extrinsic chirality and optical activity.

The paper clarifies the proper understanding of optical activity and extrinsic chirality.

Abstract

It has been assumed that optical activity can be measured by illuminating alternatively a material with left- and right- handed circular polarized light and analyzing the differential response. This simple and intuitive approach is in general incorrect, and has led to misleading idea that extrinsic chirality involves optical activity.