Regensburg 2004 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 27: Quantum Chaos

DY 27.1: Vortrag

Dienstag, 9. März 2004, 16:30–16:45, H3

Microwave measurements on dielectric quadrupole billards — •R. Schäfer and H.-J. Stöckmann — Fachbereich Physik, Philipps-Universität Marburg, Renthof 5, D-35032 Marburg, Germany

Quadrupole dielectic billiards have received a lot of attention because of their highly directed emission patterns [1] which is a welcome effect in the design of microdisc lasers. We measured transmission spectra from a fixed antenna inside the disc to a moveable antenna, thus scanning both the inside and outside region of the teflon disc. A Fourier transform of the spectra yields the pulse propagation. The long time behavior is dominated by the whispering gallery modes, which decay very slowly due to total internal reflection. The emission pattern of the quadrupole billiard is strongly influenced by the structures of its mixed phase space. Even for strong deformations with no stable islands left, a high directionality of the emission is found. This can be explained by the unstable manifolds of periodic orbits [2]. The internal dynamics of the pulse has been analyzed by means of Husimi distributions, while for the outer region the Poynting vector was calculated to obtain the emission pattern. Both are compared with classical ray dynamics taking into account the curvature-corrected Fresnel formula.

[1] J.U. Nöckel, A.D. Stone, Nature 385, 45 (1997)

[2] H.G.L Schwefel et al., arXiv:physics/0308001