Hackaday

Random lasers generate coherent light through photon scattering in a gain medium rather than using mirrors like conventional lasers. The scattering medium (rough crystals or nanoparticles) causes photons to bounce randomly, and when gain exceeds losses along certain paths, laser emission occurs. While outputs are locally coherent, they may not be globally coherent across different emission points or time scales. These devices are simple to construct, tolerant of defects, but difficult to predict. Applications include speckle-free illumination, identification markers, and biological tagging using tissue as the scattering medium.

The Random Laser