Statistically Identified Dual Type Random Lasing from Carbon Dots

Abstract

Random lasers (RLs) attract a growing interest in photonics as laser-like sources featuring specific benefits over traditional lasers for some applications. Carbon dots (CDs) are well-recognized as one of the most appealing fluorescent nanomaterials for light emitting devices. However, achieving unambiguous and controllable RL emission from CDs remains challenging. Here, we demonstrate RL emission at ∼565 nm from green emitting CDs (gCDs), and we use the emitted light as a light source for the speckle-free microscopy of biological tissues and microparticles. The emission of the CD-based RL is thoroughly studied as a function of the experimental conditions, and well-established mathematical tools in the field are used to perform a detailed statistical study of the lasing output. The CD-based RL displays ultranarrow (∼0.70 nm) emission lines over a comparatively broader (∼10 nm) background. These two emissions are due to the so-called coherent and incoherent RL. Their relative weight can be controlled by an appropriate choice of experimental conditions, allowing us to tune the characteristics of RL light. The results demonstrate the potential of gCDs as a viable alternative to environmentally unfriendly, scarce, or chemically unstable nanomaterials as gain media for RL with customizable emissions.