Active‐layer‐thickness dependence of Rabi splitting energies in ZnO microcavities

Abstract

We have investigated the active‐layer‐thickness dependence of Rabi splitting energies in ZnO microcavities. We fabricated ZnO microcavities using rf magnetron sputtering for the HfO2/SiO2 distributed Bragg reflector and pulsed‐laser deposition for the ZnO active layer. In order to control of the Rabi splitting energies, the active layer thickness was changed from λ/2 to 3λ/2. In angle‐resolved reflectance spectra at 10 K, the cavity polaritons resulting from the strong coupling between A, B, and C excitons peculiar to ZnO and the cavity photon were clearly detected. We estimated the energies of the exciton‐photon interaction, the so‐called Rabi splitting energies, from the analysis of the cavity polariton dispersions using the phenomenological Hamiltonian for the strong exciton‐photon coupling. The Rabi splitting energies markedly increase with an increase in the active layer thickness. The active‐layer‐thickness dependence of the Rabi splitting energies are explained by a semi‐quantitatively analysis. Consequently, we have succeeded in the control of the Rabi splitting energies in the ZnO microcavities. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Trapped Exciton–Polariton Condensate by Spatial Confinement in a Perovskite Microcavity

“…The square dots indicate that the coupling strength increases from 60 to 76 meV at more negative detuning energy by increasing active layer thickness (the thickness of the perovskite flakes varies from 126 to 162 nm, estimated from the dispersion curve). Similar phenomenon has been reported in a ZnO microcavity with different thicknesses of the ZnO layer and was explained as the increased overlap integral between exciton and photon field . However, this cannot compensate for the higher negative detuning energy, resulting in more photonic-like polariton and weak polariton–polariton interaction.…”

“…Similar phenomenon has been reported in a ZnO microcavity with different thicknesses of the ZnO layer and was explained as the increased overlap integral between exciton and photon field. 69 However, this cannot compensate for the higher negative detuning energy, resulting in more photonic-like polariton and weak polariton−polariton interaction. The threshold of the polariton condensate in the ground state of the LPB (blue dots) increases because of the less efficient polariton−polariton scattering.…”