Magnetic-field enhancement of the exciton-polariton splitting in a semiconductor quantum-well microcavity: The strong coupling threshold

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Abstract
We investigate the influence of strong magnetic confinement on an exciton coupled to the resonant mode of a semiconductor microcavity. Cavity mode coupling to a variety of discrete exciton resonances is described in direct relation to the quantum-well magnetoabsorption spectra. We show that the magnetic-field-enhanced vacuum Rabi splitting and time-resolved oscillation frequency obey the predicted square-root dependence on the exciton oscillator strength computed directly from the integrated absorption spectra. Anticrossing curves measured in zero field and in 11.25 T evidence an interesting three-oscillator coupling observable only at high fields due to enhanced higher-order light-hole-exciton transitions. The data are in excellent agreement with a theoretical model which deduces magnetic-field-dependent oscillator strengths and corresponding reflectance spectra from a variational calculation combined with a transfer matrix method. © 1996 The American Physical Society.