Biexcitonic resonance in the nonlinear optical response of an InAs quantum dot ensemble

Transient spectral hole burning measurements are applied to an ensemble of InAs self-assembled quantum dots. In addition to the expected exciton hole, we observe an “antihole” due to an induced absorption corresponding to the biexciton state. The biexciton binding energy is consistent with previous measurements in similar systems. The variation of the binding energy over the inhomogeneous quantum dot distribution is also measured, and is found to be consistent with expectations for strongly confined systems as a function of confinement.