Carrier dynamics of the intermediate state in InAs/GaAs quantum dots coupled in a photonic cavity under two-photon excitation

Abstract

We have studied the time-resolved intraband transition from the intermediate state to the continuum state of the conduction band in InAs/GaAs self-assembled quantum dots (QDs) embedded in a one-dimensional photonic cavity structure using two-color photoexcitation spectroscopy. The resonant energy of the photonic cavity was tuned to enhance the intraband transition with an energy smaller than the interband transition energy between the intermediate state and the quantized hole states. The interband photoluminescence intensity was observed to be drastically reduced due to the pumping out of carriers in the intermediate state using near-infrared laser light. We proposed a model describing the carrier relaxation process in the InAs/GaAs QD system, where the two-photon absorption and the Pauli blocking in QDs are considered. © 2012 American Physical Society.