Interplay of Goos-Hänchen shift and boundary curvature in deformed microdisks

As the fabrication of wavelength-scale optical microcavities is becoming feasible, extended ray models which include first-order wave corrections have attracted considerable interest. By using such a model, we find an unexpected shift of phase-space structures in momentum direction which can be attributed to the Goos-Hänchen shift in position direction and the boundary curvature ("periodic orbit shift," POS); this shift is calculated analytically for a general cavity shape. By comparing it to wave calculations in the special case of a limaçon-shaped microcavity, it is shown that mode localization occurs on the shifted, rather than the original, phase-space structures. Comparing of our analytical result to literature data, we find good agreement, which suggests that the POS may be responsible for many cases of previously reported, but unexplained, mismatches between Husimi functions and the ray-dynamical phase space.