Directional emission random lasers based on conical structure for micro-imaging

Abstract

Advancements in directional emission and partial coherence of light sources offer significant potential applications in optical communication, light detection and ranging, and optical imaging. Our study introduces a conical structure, that renders random laser emission directional, with energy primarily concentrated between −5 degrees and 5 degrees. Furthermore, the strong scattering and local surface plasmon resonance of gold nanoparticles enhance the random laser’s performance, resulting in a low threshold and high brightness. The low spatial coherence of the random laser effectively inhibits speckle formation, while its directional emission improves imaging clarity. These two complementary advantages result in the contrast-to-noise ratio of image as high as 16.74. Finally, we demonstrate the proposed random laser’s advantages in biological imaging by imaging a mouse tail section specimen. This research presents a novel light source scheme for applications in optical communication, optical imaging and damage detection.