Polariton lasing of quasi-whispering gallery modes in a ZnO microwire

We report the experimental observation of the quasi-whispering-gallery mode (quasi-WGM) polariton lasing in a one dimensional ZnO microrod cavity at room temperature. Under nonresonant optical pulsed excitation, we measure the pumping power dependence of the emission intensity and the blueshift of the polariton modes, and a fairly low lasing threshold for the quasi-WG mode is determined. We also measure the lasing threshold versus the photon-exciton detuning by dispersion simulations. These experiment results show that both of the WGMs with higher Q factors and the quasi-WGMs with lower Q factors can lase when the detuning between the optical modes and the exciton energies is optimum.