Topologically protected measurement of orbital angular momentum of light

TL;DR

This paper presents a topologically robust weak measurement scheme for accurately detecting the orbital angular momentum of light using polarization pre- and postselection, enabling rapid, spatial-resolution-free measurements resilient to phase noise.

Contribution

It introduces a novel topological measurement method for OAM that leverages spin-orbit coupling and polarization techniques, enhancing robustness and speed over traditional approaches.

Findings

Single-shot detection of OAM without spatial resolution

Measurement robustness against phase perturbations

Potential applications in optical computing and communication

Abstract

We develop a weak measurement scheme for measuring orbital angular momentum (OAM) of light based on the global topology in wave function. We introduce the spin-orbit coupling to transform the measurement of OAM to the pre- and postselected measurement of polarization. The OAM number can be precisely and promptly recognized using single-shot detection without the need for spatial resolution. More significantly, the measurement results exhibit topological robustness under random phase perturbations. This scheme has the potential to be applied as a paradigm in the OAM-based optical computing, metrology and communication.