Quantum Reference Beacon-Guided Super-Resolution Optical Focusing in Complex Media

TL;DR

This paper introduces a quantum reference beacon (QRB) technique using solid-state quantum emitters to achieve super-resolution optical focusing in complex media, surpassing the diffraction limit.

Contribution

The authors develop a novel QRB-guided wavefront shaping method utilizing nitrogen-vacancy centers for subdiffraction focusing inside complex media.

Findings

Achieved optical focusing with resolution below 186 nm.

Demonstrated QRB-guided imaging in complex media.

Enabled potential applications in deep-tissue sensing and quantum information.

Abstract

Optical random scattering is generally considered to be a nuisance of microscopy that limits imaging depth and spatial resolution. Wavefront shaping techniques have recently enabled optical imaging at unprecedented depth, but a remaining problem is also to attain super-resolution within complex media. To address this challenge, we introduce a new technique to focus inside of complex media by the use of a quantum reference beacon (QRB), consisting of solid-state quantum emitters with spin-dependent fluorescence. This QRB provides subwavelength guidestar feedback for wavefront shaping to achieve an optical focus below the microscope's diffraction limit. We implement the QRB-guided imaging approach using nitrogen-vacancy centers in diamond nanocrystals, which enable optical focusing with a subdiffraction resolution below 186 nm ($\approx \lambda/3.5\mbox{NA}$), where the microscope's NA=0.8. This QRB-assisted wavefront shaping paves the way for a range of new applications, including deep-tissue quantum enhanced sensing and individual optical excitation of magnetically-coupled spin ensembles for applications in quantum information processing.