Exploiting disorder for perfect focusing

TL;DR

This paper demonstrates that disordered scattering can be exploited to enhance focusing resolution beyond the diffraction limit using wavefront shaping, with experimental and theoretical validation showing the scattering medium's role in focus size.

Contribution

It introduces a method to use disordered media for perfect focusing, surpassing traditional limits, and provides both experimental and theoretical evidence for this approach.

Findings

Focus as small as one tenth of the diffraction limit achieved

Disordered media can be used to improve focusing resolution

The focus profile matches the theoretical optimal focus

Abstract

We demonstrate experimentally that disordered scattering can be used to improve, rather than deteriorate, the focusing resolution of a lens. By using wavefront shaping to compensate for scattering, light was focused to a spot as small as one tenth of the diffraction limit of the lens. We show both experimentally and theoretically that it is the scattering medium, rather than the lens, that determines the width of the focus. Despite the disordered propagation of the light, the profile of the focus was always exactly equal to the theoretical best focus that we derived.