Characterizing biexciton coherences with quantum spectroscopy

Abstract

The biexciton resonance in the absorption spectra of semiconductor quantum wells is analyzed with quantum-optical spectroscopy by projecting experimental pump-probe measurements into quantum-optical absorption spectra. More specifically, the measurements are converted into phase-space distributions using the cluster-expansion transformation. The quantum-optical responses can then be projected with full convergence, despite the unavoidable experimental noise. The calculations show that classical and quantum excitations produce significantly different results for the biexciton resonance. In particular, quantum-optical spectroscopy monitors the excitation-induced broadening of the biexciton resonance as a function of pump intensity much more sensitively than classical spectroscopy does.