Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 3: Quantum dots: Microcavities and photonic crystals
HL 3.3: Vortrag
Montag, 25. Februar 2008, 11:45–12:00, ER 270
Observation of Non-Resonant Dot-Cavity Coupling in Two-Dimensional Photonic Crystal Nanocavities — •Michael Kaniber, Arne Laucht, Andre Neumann, Max Bichler, and Jonathan J. Finley — Walter Schottky Institut, TU-München, Am Coulombwall 3, D-85748 Garching
We report the observation of non-resonant coupling between a single quantum dot (QD) and a photonic crystal (PC) nanocavity. Low density self-assembled In0.50Ga0.50As QDs were grown by MBE at the midpoint of a GaAs slab. Nanocavities with ωcav/Δω∼800−4000 are formed by introducing point defects into the PC. Photon auto- and cross-correlation measurements were performed on different transitions from the same QD with a small spectral detuning (|Δ|<2ω) from the cavity mode. These measurements were then repeated after Δ was increased up to +10Δω by the adsorption of molecular nitrogen. For weak detuning different transitions from the same QD exhibit pronounced photon anti-bunching in both auto- and cross-correlation measurements, demonstrating that the different transitions arise from the same dot. The auto-correlation anti-bunching dip is shallower for transitions with smaller Δ due to the presence of an additional cavity mode background emission. Upon increasing the detuning to ∼10Δω the depth of the anti-bunching recovers. Most remarkably, cross-correlation measurements between the QD and the strongly detuned mode reveal correlated emission. This observation indicates the presence of a coupling mechanism between the spectrally detuned QD and the cavity. We discuss likely mechanisms mediating the remote coupling process.