Linearly polarized lasing based on coupled perovskite microspheres
The polarization of lasing, as a fundamental property related to the emission coherence of microlasers, is one of the criteria for high quality laser beam but has been rarely investigated. Unlike conventional lasers which can be induced by highly polarized seed light or use polarizing film, the microlaser for on-chip integrated photonics circuits generally possesses low degree of polarization due to unpolarized spontaneous emission. Here, we firstly demonstrate that the Vernier effect can be used to improve the degree of polarization from ~0.2 to 0.78 based on metal halide perovskite microspheres. After coupling, linearly polarized single-mode lasing with low threshold and high quality can be obtained. In addition, by finite element method, the mode distributions of CsPbBr3 microspheres before and after coupling are analyzed systematically and clearly physical diagram of coupled resonances is presented. Our work clearly suggests coupled linearly polarized single-mode microlaser by Vernier effect would offer a real step closer to the platform for the integrated on-chip photonic.