Time-division multiplexing of the orbital angular momentum of light

TL;DR

This paper introduces an optical system that encodes orbital angular momentum of light into temporal sequences, enabling controlled pulse trains and OAM-to-time conversion for applications like digital spiral spectroscopy.

Contribution

It presents a novel optical setup using a single q-plate in a ring resonator to generate and manipulate light pulses with specific OAM and temporal properties.

Findings

Generated pulse trains with increasing OAM values.

Demonstrated OAM-to-time conversion for different OAM states.

Enabled digital spiral spectroscopy of pulsed light.

Abstract

We present an optical setup for generating a sequence of light pulses in which the orbital angular momentum (OAM) degree of freedom is correlated with the temporal one. The setup is based on a single $q$-plate within a ring optical resonator. By this approach, we demonstrate the generation of a train of pulses carrying increasing values of OAM, or, alternatively, of a controlled temporal sequence of pulses having prescribed OAM superposition states. Finally, we exhibit an "OAM-to-time conversion" apparatus dividing different input OAM states into different time-bins. The latter application provides a simple approach to digital spiral spectroscopy of pulsed light.