Speckle-Free Imaging of Biological Samples using Random laser illumination

Laser illumination is widely used in imaging but suffers from speckle noise, which reduces contrast and obscures fine details in biological samples. This limitation stems from the high spatial coherence of conventional lasers. To address this challenge, we developed a random lasing source based on Rhodamine B dye doped with polystyrene beads, which offers multiple scattering to enable optical feedback. The resulting emission combines high brightness with low spatial coherence, enabling speckle-free illumination. We utilized this source to image HeLa cells and human buccal epithelial cells, observing a significant decrease in speckle artifacts compared to traditional laser illumination methods. The enhanced image clarity and structural visibility demonstrate that random lasing is a valuable source of light for biological imaging. By combining laser-level intensity with inherently speckle-free emission, this approach opens new opportunities for high-contrast biomedical imaging of complex tissues.