Wavelength-adaptive spin-orbit orbital angular momentum management in three-wave mixing

TL;DR

This paper introduces an adjustable liquid crystal spin-orbit device for shaping bi-colour structured light, demonstrating its use in nonlinear optics for novel light modulation and characterization techniques across spectral domains.

Contribution

It presents a new wavelength-adaptive spin-orbit device integrated with three-wave mixing, enabling dynamic control and analysis of bi-colour structured light in nonlinear optics.

Findings

Successfully demonstrated bi-colour light shaping with the device.

Showed reversible switching between light characterization and unraveling.

Revealed new methods for light manipulation and analysis across spectra.

Abstract

Here we propose the use of an adjustable liquid crystal spin-orbit device to shape bi-colour structured light to create bimodal states. We demonstrate the proof-of-principle for two individual wavelengths in a nonlinear optics framework. The spin-orbit device has an inhomogeneous optical axis orientation and birefringence, allowing it to modulate two wavelengths of light with pre-selected transmission functions by simply tuning a voltage. We combine this bi-colour functionality in a nonlinear optical experiment by employing three-wave mixing in a periodically poled crystal to show how the combined effect of linear spin-orbit transformation rules and nonlinear selection rules gives rise to novel approaches for light to modulate light, and light to unravel light. We show that the roles of the nonlinear crystal and spin-orbit device can be switched to either characterise the device with known light, or unravel unknown light with the device. This synergy between spin-orbit and nonlinear optics offers a novel paradigm where light manipulates and reveals its own structure across spectral domains.