A study of optical vortices inside the Talbot interferometer

TL;DR

This paper demonstrates that the optical Talbot interferometer can effectively distinguish high-order optical vortex charges and their orbital angular momentum states using self-imaging patterns, enhancing capabilities in quantum and classical metrology.

Contribution

It introduces a method to identify high-order OAM states via Talbot patterns, improving upon previous interferometric techniques.

Findings

Talbot patterns can distinguish high-order vortex charges.

High sensitivity allows direct measurement of multiple OAM eigenvalues.

Experimental results confirm the theoretical predictions.

Abstract

The optical Talbot interferometer has been used to explore the topological charges of optical vortices. We recorded the self-imaging of a diffraction grating in the near-field regime with the optical vortex of several topological charges. Our twisted light was generated by a spatial light modulator (SLM). Previous studies showed that interferometric methods can determine the particular orbital angular momentum (OAM) states, but a large number of OAM eigenvalues are difficult to distinguish from the interference patterns. Here, we show that the Talbot patterns can distinguish the charges as well as the OAM of the vortices with high orders. Owing to high sensitivity and self-imaging of Talbot effect, several OAM eigenvalues can be distinguished by direct measurement. We assure the experimental results with our theory. The present results are useful for classical and quantum metrology as well as future implementations of quantum communications.