Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 24: Photonic crystals II

HL 24.10: Talk

Tuesday, February 26, 2008, 12:00–12:15, EW 202

GaAs Micropyramids as Optical Resonators — •Torsten Beck, Matthias Karl, Frank M. Weber, Jaime Lupaca-Schomber, Shunfeng Li, Dongzhi Hu, Daniel M. Schaadt, Heinz Kalt, and Michael Hetterich — Universität Karlsruhe (TH) and Center for Functional Nanostructures (CFN), 76128 Karlsruhe, Germany

We fabricate and study GaAs micropyramids for future applications in quantum optics. Such pyramids are promising since high quality factors and small mode volumes should be feasible. The pyramidal shape is achieved by a combination of molecular-beam epitaxy, electron-beam lithography and a wet-chemical etching process. In contrast to self-assembled growth the chemical etching method allows control of the exact geometry of the pyramids especially the angle of the facets. To obtain a high optical confinement the pyramids are placed on a GaAs/AlAs distributed Bragg reflector (DBR). Besides the emission of the embedded InAs quantum dots the micro-photoluminescence spectra of the pyramidal structures show peaks of cavity modes. We investigate the mode arrangement depending on geometry. For comparison we simulate the modes with a finite-difference time-domain method. For an improvement of the optical confinement we deposite metallic films and overgrow the pyramids with DBRs. Furthermore, coupled resonator structures are fabricated.