(color online) Sample structure of InAs/GaAs QDs with top and bottom DBRs and RF measurement setup of orthogonal excitation-detection geometry. The resonant laser guided by single mode fiber enters the QD planner waveguide through the cleaved edge of the sample, propagates along the waveguide and excites the QDs. RF is collected from the sample surface with an objective. He–Ne laser is used as an optical gate and focused on the QD through the collection objective.