2-d Microcavities: Theory and Experiments
  An overview is provided over the physics of dielectric microcavities with non-paraxial mode structure; examples are microdroplets and edge-emitting semiconductor microlasers. Particular attention is given to cavities in which two spatial degrees of freedom are coupled via the boundary geometry. This generally necessitates numerical computations to obtain the electromagnetic cavity fields, and hence intuitive understanding becomes difficult. However, as in paraxial optics, the ray picture shows explanatory and predictive strength that can guide the design of microcavities. To understand the ray-wave connection in such asymmetric resonant cavities, methods from chaotic dynamics are required. 
Jens U. Noeckel and Richard K. Chang