Plasmonic random lasing in silver nanoplate-incorporated donor–acceptor–donor organic dye-filled capillary fibers

Plasmonic random lasers (PRLs) with unique photophysical properties have attracted considerable attention owing to their promising applications in speckle-free imaging, biomedical diagnosis, and optical sensing. In this work, low-threshold PRLs were realized by infiltrating a synthesized donor–acceptor–donor organic dye into a capillary fiber coated with silver nanoplates (AgNPs). For the capillary fiber without a silver nanoplate coating, several distinct narrow emission peaks emerged and underwent a slight blueshift with increasing pump fluence, owing to the band-filling effect. After coating the capillary fiber with AgNPs, more randomly distributed emission spikes with narrower linewidths were observed. In addition, the lasing threshold was significantly reduced to 0.86 mJ/cm2, which can be attributed to the combined effects of enhanced recurrent light scattering and localized surface plasmon resonance. The as-prepared PRL, characterized by its low spatial coherence, enables speckle-reduced imaging with significantly suppressed granular artifacts and a speckle contrast as low as 0.032.