Abstract: From bio-physics to quantum simulators, many fields depend on sub-diffraction imaging of multiple point sources. Conventional wisdom suggests that using freely propagating waves to distinguish two or more identical, constantly scattering point sources is constrained by the diffraction limit. As the separation between sources decreases, their diffraction patterns increasingly overlap, complicating individual identification. We address this limitation by leveraging diffraction minima, rather than maxima, to image multiple sources simultaneously. Our theoretical and experimental results demonstrate the ability to distinguish two point sources at 1/80th of the wavelength (approximately 8 nm in our case). Contrary to expectations, our theory predicts improved measurement precision with decreasing distance between scatterers and increased scatterer density. This breakthrough paves the way for resolving clusters of optical point scatterers at minuscule fractions of the wavelength, promising advancements in various scientific and technological domains.
Preprint: https://www.biorxiv.org/content/10.1101/2024.01.24.576982v1