Ultrafast dynamics of InAs/GaAs quantum-dot microdisk lasers

The dynamical response of InAs/GaAs quantum-dot microdisk lasers has been e xperimentally investigated using femtosecond optical pumping. Because surfa ce recombination and carrier diffusion are suppressed in the quantum dots, the response speed of a quantum-dot microdisk laser is much faster than tha t 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 depe ndence of the dynamical response of the quantum-dot microdisk lasers has al so been studied over a wide temperature range. At the same pumping level, t he 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 a t higher temperature. (C) 2001 American Institute of Physics.