Solid-State Red Laser with a Single Longitudinal Mode from Carbon Dots

Miniaturized solid-state lasers with a single longitudinal mode are vital for various photonic applications. Here we prepare red-emissive carbon dots (CDs) with a photoluminescence quantum yield (PLQY) of 65.5 % by combining graphitic nitrogen doping and surface modification. High-concentration doping alters the CDs' emission from blue to red, while the electron-donating groups and polymer coating on their surfaces improve the PLQY and photostability. The CDs exhibit excellent stimulated emission characteristics, with a low threshold of amplified spontaneous emission (ASE) and long gain lifetime. A planar microcavity with only one resonant mode, which fitted with the CDs' ASE peak, was constructed. Combining the CDs and microcavity produced a solid-state laser with a single longitudinal mode, a linewidth of 0.14 nm and a signal-to-noise ratio of 14.8 dB (Q similar to 4600). Our results will aid the development of colorful solid-state micro/nano lasers with potential use in practical photonics.

Automated summary

Miniaturized solid-state lasers with single longitudinal mode are prepared by combining graphitic nitrogen doping and surface modification to create red-emissive carbon dots with high photoluminescence quantum yield. The CDs exhibit excellent stimulated emission characteristics fitting with a planar microcavity to produce a solid-state laser with single longitudinal mode.