Frankfurt 2006 – wissenschaftliches Programm
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Q: Quantenoptik und Photonik
Q 59: Photonische Kristalle IV
Q 59.3: Vortrag
Donnerstag, 16. März 2006, 11:40–11:55, HI
Dramatic enhancement of nonlinear optical frequency conversion efficiency in one-dimensional photonic crystals — •Christiane Becker1, Sean Wong1, Georg von Freymann1, and Martin Wegener2 — 1Institut für Nanotechnologie, Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft, 76021 Karlsruhe — 2Institut für Angewandte Physik, Universität Karlsruhe, 76131 Karlsruhe
Photonic crystals posses optical properties not present in any naturally occuring material. For nonlinear frequency conversion it is essential to have perfect phase matching between pumping and generated beams. In bulk material with normal dispersion the χ(3)-frequency conversion process ωsignal=2ωpump−ωseed usually doesn’t fulfill phase matching condition in collinear propagation geometry and thus stays very inefficient. In photonic crystals, however, phase matching can be achieved due to the anomalous dispersion near the photonic stop gap without being accompanied by strong absorption.
We present nonlinear FDTD-simulations using the Bloch equations with two ultrashort optical pulses of frequencies ωpump and ωseed, collinearly propagating through a 80 period dielectric stack. The parameters are chosen to match real experimental conditions. Tuning the strong ωpump-pulse to the low-energy side of the photonic stop gap reveals perfect phase matching. This results in a great enhancement of the generated ωsignal beam, over that of a bulk reference sample, by two orders of magnitude.