Regular Spectra and Universal Directionality of Emitted Radiation from a   Quadrupolar Deformed Microcavity
  We have investigated quasi-eigenmodes of a quadrupolar deformed microcavity by extensive numerical calculations. The spectral structure is found to be quite regular, which can be explained on the basis of the fact that the microcavity is an open system. The far-field emission directions of the modes show unexpected similarity irrespective of their distinct shapes in phase space. This universal directionality is ascribed to the influence from the geometry of the unstable manifolds in the corresponding ray dynamics. 
Jeong-Bo Shim, Hai-Woong Lee, Sang-Bum Lee, Juhee Yang, Songki Moon,   Jai-Hyung Lee, Kyungwon An, Sang Wook Kim