Engineering of photonic crystal (PC) cavities allows exceptional control over the resonant frequency and spatial extent of optical modes. Quantum dots (QDs), grown by Molecular Beam Epitaxy, and incorporated within the PC cavities form the ideal complement for studies of light-matter interactions at the nanoscale. Recent experiments have demonstrated the potential of such QD-PC cavity systems, including lasing behavior with extremely low thresholds. Further advances in understanding are needed to more precisely control the spatial and spectral resonances of the QDs and the PC cavity. This talk will focus on techniques for fine-tuning QD-PC cavity interactions. We will discuss a technique developed to position a single InAs QD within a PC cavity with 25 nm accuracy, allowing placement of the QD within the highest intensity regions of the cavity mode. A precision ‘digital etching’ approach allows controlled, uniform shifting of all cavity modes over a range of 80 nm in wavelength, without degradation of cavity characteristics. Finally, local AFM-induced oxidation of PC cavities allows fine tuning of individual cavity modes. These techniques should form the basis for higher-precision control of QD-PC cavity interactions.

ANL Physics Division Colloquium Schedule