Ground-state power quenching in two-state lasing quantum dot lasers

The paper analyses theoretically the quenching of the ground state (GS) power observed in InAs/GaAs quantum dot lasers when emitting simultaneously from both ground state and excited state. The model, based on a set of rate equations for the electrons, holes, and photons, shows that the power quenching is caused by the different time scales of the electron and hole intra-level dynamic, as well as by the long transport time of the holes in the GaAs barrier. The results presented also evidence how the very different dynamics of electrons and holes have other important consequences on the laser behavior; we show for example that the electron and hole carrier densities of the states resonant with lasing modes are never clamped at the threshold value, and that the damping of relaxation oscillations is strongly influenced by the hole dynamics. (C) 2012 American Institute of Physics. [doi:10.1063/1.3682574]