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Q: Quantenoptik und Photonik
Q 20: Photonische Kristalle I
Q 20.2: Vortrag
Dienstag, 14. März 2006, 10:55–11:10, HI
Near field studies of resonances in multistep photonic crystal heterostructure nanocavities. — •Sushil Mujumdar1, A. Femius Koenderink2, and Vahid Sandoghdar1 — 1Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland. — 2FOM-Institute for Atomic and Molecular Physics (AMOLF), Kruislaan 407, 1098 SJ Amsterdam, The Netherlands.
We report on near-field studies of resonances in photonic crystal nanocavities realized in thin GaAs membranes. The nanocavities were created under a multistep photonic heterostructure design, wherein five crystal slabs, with lattice constants a1, a2, a1, a2 and a1 respectively (a1>a2) were seamlessly welded together[1]. A collinear W1 waveguide created through the structure exhibits an offset in the band diagram for the guided mode in the regions with different lattice constants. The confinement in the spatially narrow (width 2a1) region yields resonances of quality factors ∼104, depending on the width of the a2 region. An optical fiber tip mounted in a shear-force setup explored the near-field distribution of light in the nanocavity on and off resonance frequencies. The high-resolution (< 100 nm) intensity map in the nanocavity at the resonant frequency shows excellent agreement with 3D finite difference time domain simulations. Furthermore, the pre-resonant evolution of light intensity in the nanocavity shows an interesting behaviour as the mode-gap is scanned in frequency.
[1] Samples were fabricated by the Nanodevices for Photonics and Electronics group, Institute of Experimental Physics, University of Würzburg.