Subwavelength focusing inside an open disordered medium by time reversal at a single point antenna

TL;DR

This paper demonstrates that broadband time reversal at a single antenna, combined with near-field interactions and multiple scattering, enables subwavelength light focusing inside open disordered media, comparable to ideal cavity conditions.

Contribution

It introduces a theoretical approach showing subwavelength focusing in open media using single-point time reversal, expanding potential applications in optical imaging and nanoscale control.

Findings

Achieves subwavelength focusing comparable to closed cavities

Utilizes broadband time reversal with near-field interactions

Enables super-resolved optical imaging in complex media

Abstract

We study theoretically light focusing at subwavelength scale inside a disordered strongly scattering open medium. We show that broadband time reversal at a single point antenna, in conjunction with near-field interactions and multiple scattering, produces spatial focusing with a quality comparable to that obtained in an ideal closed cavity. This gives new perspectives for super-resolved optical imaging and coherent control of single nanosources or absorbers in complex media.