Determination of oscillator strength of confined excitons in a semiconductor microcavity

Abstract

We have achieved a significant experimental Rabi-splitting (3.4 meV) for confined polaritons in a planar semiconductor λ microcavity for only a single quantum well (SQW) of GaAs (10 nm) placed at the antinode. The Rabisplitting phenomena are discussed in detail based on the semiclassical theory, where two coupled harmonic oscillators (excitons and photons) are used to describe the system. In this way, we can obtain the dispersion curve of polaritons, the minimum value for the cavity re2ectance and the oscillator strength to reach the strong coupling regime. This approach describes an ensemble of excitons confined in a SQW and includes a dissipation component. The results present a weak coupling regime, where an enhanced spontaneous emission takes place, and a strong coupling regime, where Rabi-splitting in the dispersion curve can be observed. The theoretical results are confronted with experimental data for the re2ectance behavior in resonant and off-resonant conditions and present a great accuracy. This allows us to determine the oscillator strength of the confined excitons in the SQW with great precision. © E.A. Cotta, P.M.S. Roma, 2014.