Strong exciton–photon coupling and polariton lasing in GaN microrod

Abstract

We report on the studies of strong exciton photon coupling and polariton lasing at room temperature from single GaN microrods grown by metal-organic vapor phase epitaxy technique. Emission spectra were recorded at room temperature by exciting GaN microrods with pulsed Nd:YAG laser of 355 nm wavelength at different excitation power density. Clear mode formation corresponding to Whispering gallery modes in GaN microrod cavity has been observed. Strong exciton–photon coupling as well as large Rabi splitting energy of maximum 400 ± 40 meV has been observed from the microrods. This is attributed to the formation of new quasi-particles named polaritons with much lighter mass than free electron mass. Among those polariton modes, one of the modes increases super linearly with the increase in excitation power density which is an indication of polariton lasing.