Room-temperature near-infrared whispering-gallery-mode lasing from two-dimensional CdSe microplates

Abstract

Near-infrared (NIR) micro/nanolasers are attractive for their potential in biological and nonlinear optics applications. Despite the great advances, challenge remains due to low quantum efficiency and small exciton binding energy. Herein, we demonstrate a planar room-temperature NIR microlaser based on two-dimensional CdSe microplates (MPs). Whispering-gallery-mode lasing is achieved from individual CdSe MPs with a typical threshold (∼38.4 μJ cm⁻²) and spectral coherence (∼0.95 nm). Time-resolved photoluminescence measurements suggest that the lasing originates from the electron–hole plasma recombination. The better lasing performance and photostability of hexagonal MPs over their triangular counterparts are attributed to stronger light confinement, as verified by theoretical simulations. Moreover, the size-dependent lasing threshold study reveals that the threshold of hexagonal MPs scales inversely with the square of cavity size. These CdSe-based microlasers can be potentially used for on-chip integration.