A new study from the University of Portsmouth has outlined a possible way to improve how we distinguish between two closely spaced light sources, an issue that has long challenged classical imaging systems.

The approach, published in Physical Review Applied, uses principles from quantum physics to estimate small separations between light-emitting objects, with potential future applications in fields like microscopy, astronomy, and remote sensing.

The research suggests that a relatively simple quantum set-up could be used to extract spatial information that is traditionally limited by the so-called Rayleigh criterion—a rule dating back over a century that defines the limits of classical resolution.