A color-switchable ring-shaped random laser in momentum space

TL;DR

This paper presents a novel color-switchable ring-shaped random laser in momentum space, achieved by coupling a random gain layer with an optical fiber, enabling low-threshold, directional, and tunable multi-color lasing for high-quality imaging.

Contribution

It introduces a simple method to create a color-switchable, ring-shaped random laser with low threshold and directional emission using fiber coupling and selective coating.

Findings

Achieved red and yellow random lasers with low threshold and good directionality.

Demonstrated ring-shaped lasing in momentum space for high-quality imaging.

Enabled flexible color switching by moving the pump position.

Abstract

A color-switchable random laser is designed through directly coupling random laser with a commercial optical fiber. By using a simple approach of selectively coating the random gain layer on the surface of fiber, the red and yellow random lasers are respectively achieved with low threshold and good emission direction due to the guiding role of optical fibers. Moreover, the unique coupling mechanism leads to the random lasing with ring-shape in momentum space, indicating an excellent illuminating source for high-quality imaging with an extremely low speckle noise. More importantly, random lasing with different colors can be flexible obtained by simply moving the pump position.