ABSTRACT
Lasing effects based on individual quantum dots have been investigated in optically pumped high-Q micropillar cavities. We demonstrate a lowering of the threshold pump power from a off-resonance value of 37 microW to 18 microW when an individual quantum dot exciton is on-resonance with the cavity mode. Photon correlation studies below and above the laser threshold confirm the single dot influence. At resonance we observe antibunching with g((2))(0) = 0.36 at low excitation, which increases to 1 at about 1.5 times the threshold. In the off-resonant case, g((2))(0) is about 1 below and above threshold.
Subject(s)
Computer-Aided Design , Lasers, Semiconductor , Models, Theoretical , Quantum Dots , Transducers , Computer Simulation , Equipment Design , Equipment Failure AnalysisABSTRACT
We report the observation of whispering gallery modes (WGM) in high quality GaAs/AlAs pillar microcavities defined by electron-beam lithography and electron cyclotron resonance reactive ion etching. Photoluminescence experiments, conducted using InAs quantum dots as an internal probe, reveal a remarkably simple WGM spectrum, consisting of a single series of TE modes. For diameters ranging from 3 to 4 mum, Q-factors in excess of 15 000 were measured, allowing for WGM lasing. Noticeably, sub-micron diameter micropillars also display high Qs (~ 1000), close to the limit set by intrinsic radiative losses. These results open the way to the development of original microlasers and improved quantum-dot single photon sources.