Regensburg 2004 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 20: Photonische Kristalle IV
HL 20.5: Vortrag
Dienstag, 9. März 2004, 16:15–16:30, H17
Cavity QED phenomena in Photonic Crystal Microcavities containing self-assembled Quantum Dots — •A. F. Kreß, F. Hofbauer, H. J. Krenner, D. Schuh, R. Meyer, and J. J. Finley — Walter Schottky Institut, TU München, 85748 Garching, Germany
We present optical investigations of active photonic crystal defect mircocavities (PCµC) formed from a hexagonal lattice of air-holes in a GaAs-(Al)GaAs slab waveguide. Incorporation of one or more layers of self assembled InGaAs quantum dots (QD) into the waveguide enable us to directly probe the nature of the cavity modes using spatially resolved photoluminescence (µPL) spectroscopy. Moreover, cavity-QED phenomena have been directly observed using time resolved spectroscopy.
The fully localised PCµC modes show strongly enhanced light emission with Q>500 for a modevolume of ∼ 3(λ /n)3. Time resolved measurements clearly demonstrate Purcell enhancement of the spontaneous emission rate with Purcell factors up to ∼4 having been observed.
Control of the design and symmetry of the PCµC allows us to engineer the cavity modes. µPL measurements on a series of H2 PCµCs demonstrate our ability to tune the wavelength of the cavity modes over ∼±30nm around ∼950nm with a precision better than ∼1nm. Tuneable cavity states are investigated in different hexagonal crystals and exhibit mode structure in good accordance with our calculations. Improved PCµC designs for reduced symmetry ultra high Q-cavities will also be presented. Finally, we will discuss a device concept for an electronically tuneable PCµC for planned single QD cavity QED experiments.