Line Width-Tunable Random Laser Based on ManipulatingPlasmonic Scattering

Line width-tunable lasers have wide applications in the fields of high-resolution spectroscopy, optical communications, and other industry and scientific research. Here, manipulating plasmonic scattering of metal particles with plenty of nanogaps is proposed as an effective method to achieve line width-tunable random lasers. Assisted by the nonlinear optical effect of the surrounding medium, the multiscale scattering material demonstrates the transition from local scattering of nanogaps to large-scale profile scattering by increasing the pump power density. Based on these two scattering processes, random lasers can be continuously driven from a narrow-line-width configuration to a broad-line-width regime, demonstrating that line width variation exceeds 2 orders of magnitude. This phenomenon may provide a platform for further studying the conclusive mechanism of random lasing and supply a new approach to tune the line width of random lasers for further applications in high-illumination imaging and biology detection.