Ultrafast photonic rainbow with controllable orbital angular momentum

TL;DR

This paper reports the first generation of multicolor ultrafast vortex beams with controllable orbital angular momentum using cascaded four-wave mixing in YAG, enabling new degrees of freedom for light manipulation and applications.

Contribution

Introducing a novel method to generate multicolor ultrafast vortex beams with controllable OAM using cascaded four-wave mixing in YAG.

Findings

Generated up to 9 multicolor ultrafast vortex sidebands.

Controlled topological charges matching theoretical predictions.

Potential applications in multicolor experiments and optical manipulation.

Abstract

Increasing any degree of freedom of light beam may open a wide application area of this special light beam. Vortex beam with a dimension of orbital angular momentum (OAM) as a useful light source has been widely applied in many fields. Here, unique multicolor concentric ultrafast vortex beams (MUCU-VBs), which are also named ultrafast photonic rainbow, with controllable orbital angular momentum are firstly generated using cascaded four-wave mixing (CFWM) in an yttrium aluminum garnet (YAG) plate. Up to 9 multicolor concentric annular ultrafast vortex sidebands are generated simultaneously. The topological charges of the sidebands, which are controllable by changing the topological charges of the two input pump beams, are measured and in according with the theoretical analysis very well. The novel MUCU-VBs can be manipulated simultaneously in temporal, spatial, spectral domains and OAM state, which open more than one new degree of freedoms of vortex light beam and will be of wide and special applications, such as multicolor pump-probe experiments, simultaneous microparticle manipulation and exploring, and optical communication. Moreover, the special focusing properties of the multicolor ultrafast sidebands, such as multi-focus of different wavelengths, may further extend their application area.