Generation of coupled orbital angular momentum modes from an optical vortex parametric laser source

TL;DR

This paper demonstrates the generation of coupled orbital angular momentum modes using a vortex optical parametric oscillator, with tunable wavelengths and high efficiency, advancing control over OAM in laser sources.

Contribution

It introduces a method to generate coupled OAM modes from a vortex OPO using a short coherence pump source, and extends to higher-order vortex outputs with longer coherence pumps.

Findings

Generated flower (wheel) OAM modes from vortex pump

Achieved tunable wavelength outputs in signal and idler

Maximum signal energy of 1.2 mJ with 15.6% efficiency

Abstract

We report on the generation of flower (wheel) modes, which manifest coupled orbital angular momentum (OAM) modes, from a vortex pumped optical parametric oscillator simply by employing a pump source with a short temporal coherence time. This vortex oscillator was also developed to generate a further higher-order vortex signal output with $l_s=2-4$ by replacement of the pump source with a longer coherence time. The signal and idler outputs were tuned within wavelength ranges of 745-955 nm and 1200-1855 nm, respectively. The maximum signal output energy of 1.2 mJ was measured with an optical efficiency of 15.6%.