Coherent transfer of optical orbital angular momentum in multi-order Raman sideband generation

TL;DR

This paper demonstrates the coherent transfer of optical orbital angular momentum across multiple Raman sidebands using experimental interference techniques, confirming theoretical selection rules for topological charges.

Contribution

It introduces a method to generate and analyze Raman sidebands with optical vortices, revealing discrete topological charges consistent with cascaded Raman process predictions.

Findings

Topological charges are discrete in all orders.

Interference patterns confirm helicity and topological charge transfer.

Selection rules for topological charges are validated.

Abstract

Experimental results from the generation of Raman sidebands using optical vortices are presented. By generating two sets of sidebands originating from different locations in a Raman active crystal, one set containing optical orbital angular momentum and the other serving as a reference, a Young's double slit experiment was simultaneously realized for each sideband. The interference between the two sets of sidebands was used to determine the helicity and topological charge in each order. Topological charges in all orders were found to be discrete and follow selection rules predicted by a cascaded Raman process.