Improved Spatial Resolution Achieved by Chromatic Intensity Interferometry

TL;DR

This paper demonstrates that chromatic intensity interferometry with color erasure detectors can significantly surpass diffraction limits, achieving higher spatial resolution and phase recovery in astronomical imaging.

Contribution

The work introduces an experimental method using color erasure detectors to enhance spatial resolution beyond diffraction limits and recover phase information in intensity interferometry.

Findings

Achieved 40-fold resolution improvement over diffraction limit.

Successfully measured source separation of 4.2 mm at 1.43 km.

Recovered Fourier phase information with modest noise.

Abstract

Interferometers are widely used in imaging technologies to achieve enhanced spatial resolution, but require that the incoming photons be indistinguishable. In previous work, we built and analyzed color erasure detectors which expand the scope of intensity interferometry to accommodate sources of different colors. Here we experimentally demonstrate how color erasure detectors can achieve improved spatial resolution in an imaging task, well beyond the diffraction limit. Utilizing two 10.9 mm-aperture telescopes and a 0.8 m baseline, we measure the distance between a 1063.6 nm source and a 1064.4 nm source separated by 4.2 mm at a distance of 1.43 km, which surpasses the diffraction limit of a single telescope by about 40 times. Moreover, chromatic intensity interferometry allows us to recover the phase of the Fourier transform of the imaged objects - a quantity that is, in the presence of modest noise, inaccessible to conventional intensity interferometry.