Ultrafast dynamics of InAs/GaAs quantum-dot microdisk lasers

Abstract

The dynamical response of InAs/GaAs quantum-dot microdisk lasers has been experimentally investigated using femtosecond optical pumping. Because surface recombination and carrier diffusion are suppressed in the quantum dots, the response speed of a quantum-dot microdisk laser is much faster than that of a quantum-well microdisk laser. A turn-on time as short as 7.8 ps has been achieved in a quantum-dot microdisk laser at 5 K. The temperature dependence of the dynamical response of the quantum-dot microdisk lasers has also been studied over a wide temperature range. At the same pumping level, the turn-on time of the laser decreases as the temperature increases from 5 to 120 K. Such behavior may be due to a faster carrier relaxation process at higher temperature.