Multiparameter estimation for the superresolution of two incoherent sources

TL;DR

This paper demonstrates a method for simultaneously estimating multiple parameters of two incoherent optical sources in the superresolution regime, surpassing traditional diffraction limits and approaching quantum bounds.

Contribution

The authors experimentally achieve joint estimation of separation, centroid, and brightness of incoherent sources using spatial-mode demultiplexing, demonstrating superresolution capabilities in a single setup.

Findings

Successfully estimate parameters below the diffraction limit.

Achieve sensitive joint estimation over various scene configurations.

Benchmark performance against quantum Cramér-Rao bounds.

Abstract

We experimentally demonstrate the simultaneous estimation of the three parameters characterizing a pair of incoherent optical sources in the sub-Rayleigh regime, enabling super-resolved scene characterization. Using spatial-mode demultiplexing (SPADE) with two demultiplexers--one deliberately shifted--we determine separations well below the diffraction limit and achieve sensitive joint estimation of separation, centroid, and relative brightness over a broad range of scene configurations in a single experimental setting. We benchmark our performance using Fisher-information-based Cram\'er-Rao bounds, and discuss the corresponding quantum limits. We investigate two complementary scenarios: a realistic case with slightly non-identical sources, and an idealized case of indistinguishable sources.