Determination of oscillator strength of confined excitons in a semiconductor microcavity

TL;DR

This paper reports the experimental observation and theoretical analysis of Rabi-splitting in confined polaritons within a semiconductor microcavity, enabling precise determination of exciton oscillator strength in a single quantum well.

Contribution

It introduces a semiclassical coupled oscillator model to accurately describe polariton dispersion and extract oscillator strength in a semiconductor microcavity with a single quantum well.

Findings

Achieved a 3.4 meV Rabi-splitting in a GaAs quantum well microcavity.

Demonstrated strong and weak coupling regimes with detailed theoretical and experimental analysis.

Precisely determined the oscillator strength of confined excitons.

Abstract

We have achieved a significant experimental Rabi-splitting (3.4 meV) for confined polaritons in a planar semiconductor $\lambda$ microcavity for only a single quantum well (SQW) of GaAs (10 nm) placed at the antinode. The Rabi-splitting 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 reflectance 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 reflectance 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.