Whispering-gallery-mode based CH3NH3PbBr3 perovskite microrod lasers with high quality factors

TL;DR

This paper reports the development of high-Q whispering-gallery-mode perovskite microrod lasers with significantly improved FWHM and Q factors, achieved through partial excitation and high-quality crystal synthesis.

Contribution

The study introduces a novel partial excitation method for perovskite microrods that enhances light confinement and laser quality, achieving record-high Q factors.

Findings

FWHM at threshold reduced to around 0.1 nm

Q factor exceeded 5000

Single-mode or few-mode laser emission achieved

Abstract

Lead halide perovskite based micro- and nano- lasers have been widely studied in past two years. Due to their long carrier diffusion length and high external quantum efficiency, lead halide perovskites have been considered to have bright future in optoelectronic devices, especially in the "green gap" wavelength region. However, the quality (Q) factors of perovskite lasers are unspectacular compared to conventional microdisk lasers. The record value of full width at half maximum (FWHM) at threshold is still around 0.22 nm. Herein we synthesized solution-processed, single-crystalline CH3NH3PbBr3 perovskite microrods and studied their lasing actions. In contrast to entirely pumping a microrod on substrate, we partially excited the microrods that were hanging in the air. Consequently, single-mode or few-mode laser emissions have been successfully obtained from the whispering-gallery like diamond modes, which are confined by total internal reflection within the transverse plane. Owning to the better light confinement and high crystal quality, the FWHM at threshold have been significantly improved. The smallest FWHM at threshold is around 0.1 nm, giving a Q factor over 5000.