Single-mode lasing in CH₃NH₃PbBr₃ perovskite microplates via micro-manipulation

Abstract

Recently, lead halide perovskites have achieved extensive research attentions, for their low-cost fabrication process, large absorption coefficient and long electron-hole diffusion length. The optically pumped micro- and nano- lasers have been demonstrated and the estimated quantum yields even approach 100%. In this manuscript, we synthesized perovskite microplates in our experiment with one-step solution self-assembly method. However, as most of the perovskite microplates have large sizes, the lasing modes of them are usually multiple modes. To improve the monochromaticity of the perovskite microlasers, we have introduced a simple way to control the mode number in the microplates. By pushing another microplate to attach the lasing one, the number of lasing modes has been reduced and single-mode lasing emission has been realized in a microplate more than 10 μm. It is to be noted that, the additional microplate has huge loss, so it wouldn't lase during the manipulation. The corresponding extinction ratio can be more than 10 dB. Our experimental data indicates that the attached microplate would increase the loss of some lasing modes which have strong field distribution at the connected area. And the large mode spacing and the extremely narrow gain region plays a key role in formation of the single-mode lasing emission. We believe that this feasible and simple method is not limited in Fabry-Perot modes, it could be further used in other microcavities and will find its potential applications in the lead halide perovskite microplate lasers.