Random Plasmonic Laser Based on Bismuth/Aluminum/Yttria/Silver Co-Doped Silica Fiber with Microcavity Shaped Tip

In this study, we demonstrate a proof of principle of an all-fiber random laser due to the plasmonic effect. This was achieved with a fiber co-doped with bismuth/aluminum/yttria/silver in which a microsphere (microcavity) at the fiber’s tip was made using a splicing machine. The presence of bismuth and silver nanoparticles in the fiber along with bismuth–aluminum phototropic centers stands behind the observed phenomenon. The effect can be attributed to the in-pair functioning of this unit as an active medium and volumetric plasmonic feedback, resulting in lasing at 807 nm under 532 nm pumping with a notably low (~2 mW) threshold.