Excitation-polarization-dependent dynamics of polariton condensates in the ZnO microwire at room temperature

Abstract

Based on ZnO microcavities with high quality factors, where the gain medium exhibits confinement of wave packets due to the intrinsically formed whispering gallery microcavity, strong coupling between excitons and cavity photons can be obtained at room temperature resulting in hybrid quasiparticles, e.g. exciton polaritons. In this work, polariton condensation is induced under the non-resonant excitation by linearly polarized femtosecond pulses with different polarization directions. The dynamical angle-resolved k-space spectra of the photoluminescence emission of polariton condensates are measured with sub-picosecond resolution by the self-developed femtosecond angle-resolved spectroscopic imaging technique. Our results show that the ultrafast dynamics of polariton condensation is sensitive to the polarization direction of the excitation pulses which can be explained qualitatively by the combined effect of selective excitation of distinct exciton modes in the sample and the effective coupling strength of the excitation pulses in the ZnO microcavity for various polarization directions. This work strengthened the understanding of the underlying physics of the condensation process for cavity exciton polaritons at room temperature.room temperature.

Size and Morphology Modulation in ZnO Nanostructures for Nonlinear Optical Applications: A Review

“…In order to better understand ZnO’s optical processes under laser excitation, it is necessary to characterize its NLA behavior. Some studies have been conducted on the nonlinear properties of ZnO in a narrow wavelength range or using a megahertz repetition-rate laser. − At present, the dynamic behaviors of ZnO semiconductor materials in different wavebands and pulse time domains have also been reported. − …”