Directional emission from asymmetric resonant cavities
  Asymmetric resonant cavities (ARCs) with highly non-circular but convex cross-sections are predicted theoretically to have high-Q whispering gallery modes with very anisotropic emission. We develop a ray dynamics model for the emission pattern and present numerical and experimental confirmation of the theory. 
Jens U. Noeckel, A. Douglas Stone, Gang Chen, Helene L. Grossman and   Richard K. Chang