title: Separatrix modes in weakly deformed microdisk cavities.
abstract: Optical modes in deformed dielectric microdisk cavities often show an unexpected localization along unstable periodic ray orbits. We reveal a new mechanism for this kind of localization in weakly deformed cavities. In such systems the ray dynamics is nearly integrable and its phase space contains small island chains. When increasing the deformation the enlarging islands incorporate more and more modes. Each time a mode comes close to the border of an island chain (separatrix) the mode exhibits a strong localization near the corresponding unstable periodic orbit. Using an EBK quantization scheme taking into account the Fresnel coefficients we derive a frequency condition for the localization. Observing far field intensity patterns and tunneling distances, reveals small differences in the emission properties.
authors.forename: Chang-Hwan
authors.initials: CH
authors.lastname: Yi
authors.forename: Julius
authors.initials: J
authors.lastname: Kullig
authors.forename: Ji-Won
authors.initials: JW
authors.lastname: Lee
authors.forename: Ji-Hwan
authors.initials: JH
authors.lastname: Kim
authors.forename: Hyeon-Hye
authors.initials: HH
authors.lastname: Yu
authors.forename: Jan
authors.initials: J
authors.lastname: Wiersig
authors.forename: Chil-Min
authors.initials: CM
authors.lastname: Kim