Nonlinear manipulation of orbital angular momentum spectra with second- and third- harmonic generation in a quasi-periodically poled crystal

TL;DR

This paper demonstrates a novel nonlinear method to manipulate optical orbital angular momentum spectra using simultaneous second- and third-harmonic generation in a specialized nonlinear crystal, enabling new applications in classical and quantum optics.

Contribution

It introduces a new approach for nonlinear manipulation of OAM spectra using quasi-periodically poled crystals, especially for customized harmonic spectra at shorter wavelengths.

Findings

Confirmed theoretical predictions with experimental results.

Achieved manipulation of OAM spectra at shorter wavelengths.

Enabled potential applications in multiplexing and high-dimensional quantum information.

Abstract

Optical orbital angular momentum (OAM), as an important degree of freedom of light, has been attracted extensive attention, due to its intrinsic feature of natural discrete infinite dimension. Manipulation of OAM spectra is crucial for many impressive applications from classical to quantum realms, in particular, nonlinear manipulation of OAM spectra. Here we realized the nonlinear manipulation of OAM spectra by using the simultaneous second- and third-harmonic generation in a single nonlinear crystal of quasi-periodically poled potassium titanyl phosphate, for fundamental waves with a variety of OAM spectra, especially for customized OAM spectra of the second and third harmonics. The experimental results confirmed the theoretical predictions. Our approach not only provides a novel way to manipulate OAM spectra at new shorter wavelengths that are hard to be directly generated, but also may find new applications towards multiplexing in classical optics and high-dimensional information processing in quantum optics.