弯曲氧化锌微米线微腔中的回音壁模

本文用微区共聚焦荧光光学显微镜在垂直于氧化锌微米线c轴的方向测量微米线上不同位置的光谱,通过对比直的和弯曲的微米线上TE和TM偏振的光谱,观察到了弯曲氧化锌微米线中不同位置的回音壁模式的移动,其机理是在弯曲应力作用下激子能级发生了移动,带边附近的介电常数也随之变化,导致微腔中的回音壁模式发生移动.

Whisp ering gallery mo des in a bent ZnO microwire

Micro-cavities play an important role in the light-matter interaction. The cross section of wurtzite-structured ZnO microwire is a hexagon, which gives a high quality factor. Exciton-polariton, micro-and nanowire lasers and polariton condensation have been investigated using the micro-cavities of ZnO microwires at room temperature. Strain, which changes the dielectric index of a material, is one of the methods to tune the interaction between the light and the matter. In this work, the photoluminescence spectra of strain free and bent ZnO microwires are measured across the wires, and the modes shifts are observed only in the bent one near the band edge. Shifting of the cavity modes across the wire can be observed in both TE and TM polarized spectra. For a bent ZnO microwire, the microcavity can be modified by the strain from bending, and the exciton energies may shift due to the strain. The shifted exciton energy induces a change of dielectric constant, resulting in the shifting of the cavity modes across the microwire.
Keywords：ZnO microwiremicro-cavitywhispering gallery modestrain