Towards optical toroidal wavepacket through tightly focusing of cylindrical vector two dimensional spatiotemporal optical vortex

TL;DR

This paper introduces a novel method for generating highly confined optical wavepackets with toroidal topology using tightly focused cylindrical vector 2D spatiotemporal optical vortices, opening new avenues in photonics and quantum technologies.

Contribution

It proposes the first cylindrical vector 2D-STOVs with orthogonal transverse OAMs and investigates their tight focusing to produce toroidal wavepackets with controllable topologies.

Findings

Generation of toroidal wavepackets with Yo-Yo ball shape

Radially polarized 2D-STOVs produce magnetic toroidal wavepackets

Azimuthally polarized 2D-STOVs produce electric toroidal wavepackets

Abstract

Spatiotemporal optical vortices (STOVs) carrying transverse orbital angular momentum (OAM) are of rapidly growing interest for the field of optics due to the new degree of freedom that can be exploited. In this paper, we propose cylindrical vector two dimensional STOVs (2D-STOVs) containing two orthogonal transverse OAMs in both x-t and y-t planes for the first time, and investigate the tightly focusing of such fields using the Richards-Wolf vectorial diffraction theory. Highly confined spatiotemporal wavepackets with polarization structure akin to toroidal topology is generated, whose spatiotemporal intensity distributions resemble the shape of Yo-Yo balls. Highly focused radially polarized 2D-STOVs will produce wavepackets towards transverse magnetic toroidal topology, while the focused azimuthally polarized 2D-STOVs will give rise to wavepackets towards transverse electric toroidal topology. The presented method may pave a way to experimentally generate the optical toroidal wavepackets in a controllable way, with potential applications in electron acceleration, photonics, energy, transient light-matter interaction, spectroscopy, quantum information processing, etc.