Space Time Nonseparable Electromagnetic Vortices

TL;DR

This paper introduces space-time nonseparable electromagnetic vortices with complex topological structures, advancing high-dimensional information transfer and electromagnetic field control.

Contribution

It presents a new family of space-time nonseparable electromagnetic vortices and applies quantum-mechanics methods to characterize their properties.

Findings

Exhibit complex spatiotemporal topological structures

Contain multiple singularities and energy backflow

Potential applications in information transfer and toroidal electrodynamics

Abstract

In structured light with controllable degrees of freedom (DoFs), the vortex beams carrying orbital angular momentum (OAM) give access to provide additional degrees of freedom for information transfer, and in classic field, the propagation invariant space time electromagnetic pulses are the possible approach to high dimensional states. This paper arose an idea that coupling the space polarization nonseparable states of vortex beams and space time nonseparable states of spatiotemporal pulse can generate numerous unique and beneficial effects. Here, we introduce an family of space time nonseparable electromagnetic vortices (STNEV). The pulses exhibit complex and robust spatiotemporal topological structure of the electromagnetic fields, multiple singularities in the Poynting vector maps and distributions of energy backflow. We apply a quantum-mechanics methodology for quantitatively characterizing space time nonseparability of the pulse. Our findings facilitate their applications in fields of information transfer, toroidal electrodynamics and inducing transient excitations in matter.