Room-Temperature Continuous-Wave Random Lasing from a GaAs Thin Film

The development of optically pumped continuous-wave (CW) random lasers is critical for advancing high-density integrated optoelectronic devices. However, achieving room temperature CW random lasing in GaAs thin films remains challenging due to insufficient optical feedback and thermal instability. This Article systematically investigates random lasing based on GaAs/AlAs/GaAs thin film under CW optical pumping. By introducing a low refractive index AlAs interlayer with controlled surface roughness, we realize the enhancement of scattering efficiency and optical feedback while preserving high crystal quality. The optimized structure exhibits a net optical modal gain of 64 cm –1 and a high characteristic temperature of 221 K, indicating superior light amplification efficiency and thermal stability. Finally, a proof-of-concept demonstration of speckle-free laser imaging using the low spatial coherence of the random lasers has been conducted. This research provides valuable insights into the development of GaAs-based CW random lasers and highlights their potential for applications in optical communications, sensing, and biomedical imaging.