Random lasing in an Anderson localizing optical fiber

TL;DR

This paper demonstrates a directional, stable random laser in a disordered optical fiber operating via Anderson localization, enabling low-coherence laser emission with potential applications in optical imaging.

Contribution

It introduces a new type of random laser based on Anderson localization that is highly directional and spectrally stable, overcoming limitations of previous random lasers.

Findings

Laser operates in Anderson localization regime

Output beam is highly directional and stable

Low spatial coherence suitable for imaging applications

Abstract

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.