Speckle-free laser imaging

TL;DR

This paper demonstrates that low-coherence random lasers enable speckle-free, high-resolution full-field imaging even in scattering environments, improving image quality over traditional coherent laser illumination.

Contribution

It introduces the use of engineered random lasers with low spatial coherence for speckle-free imaging, advancing imaging quality in scattering media.

Findings

Random lasers provide low spatial coherence suitable for speckle-free imaging.

Images with random laser illumination have higher resolution than those with coherent sources.

Random lasers are versatile for various full-field imaging applications.

Abstract

Many imaging applications require increasingly bright illumination sources, motivating the replacement of conventional thermal light sources with light emitting diodes (LEDs), superluminescent diodes (SLDs) and lasers. Despite their brightness, lasers and SLDs are poorly suited for full-field imaging applications because their high spatial coherence leads to coherent artifacts known as speckle that corrupt image formation. We recently demonstrated that random lasers can be engineered to provide low spatial coherence. Here, we exploit the low spatial coherence of specifically-designed random lasers to perform speckle-free full-field imaging in the setting of significant optical scattering. We quantitatively demonstrate that images generated with random laser illumination exhibit higher resolution than images generated with spatially coherent illumination. By providing intense laser illumination without the drawback of coherent artifacts, random lasers are well suited for a host of full-field imaging applications from full-field microscopy to digital light projector systems.