Random lasing in an Anderson localizing optical fiber

A directional random laser mediated by transverse Anderson localization in a disordered glass optical fiber is reported. Previous demonstrations of random lasers have found limited applications because of their multi-directionality and chaotic fluctuations in the laser emission. The random laser presented in this paper operates in the Anderson localization regime. The disorder induced localized states form isolated local channels that make the output laser beam highly directional and stabilize its spectrum. The strong transverse disorder and longitudinal invariance result in isolated lasing modes with negligible interaction with their surroundings, traveling back and forth in a Fabry–Perot cavity formed by the air–fiber interfaces. It is shown that if a localized input pump is scanned across the disordered fiber input facet, the output laser signal follows the transverse position of the pump. Moreover, a uniformly distributed pump across the input facet of the disordered fiber generates a laser signal with very low spatial coherence that can be of practical importance in many optical platforms including image transport with fiber bundles. Random lasers: Stable, directional output realized A random laser that produces spectrally stable and highly directional light could lead to new applications in micro and nanophotonics. Random lasers produce laser light from disordered materials, such as powders and porous glasses. They are attractive for creating useful optical structures, but their output suffers from multidirectionality and chaotic fluctuations. Now, Arash Mafi's group from the University of New Mexico and collaborators from Clemson University and University of California, San Diego in the USA have fabricated a random laser that produces highly directional and stable light thanks to local channels that form due to localized states induced by the disorder. The laser operated by confining light waves within a disordered glass optical fiber. It generated light with a very low spatial coherence and could find application in the transportation of images using fibre bundles.