Optical parametric oscillators in isotropic photonic crystals and   cavities: 3D time domain analysis
  We investigate optical parametric oscillations through four-wave mixing in resonant cavities and photonic crystals. The theoretical analysis underlines the relevant features of the phenomenon and the role of the density of states. Using fully vectorial 3D time-domain simulations, including both dispersion and nonlinear polarization, for the first time we address this process in a face centered cubic lattice and in a photonic crystal slab. The results lead the way to the development of novel parametric sources in isotropic media. 
Claudio Conti, Andrea Di Falco, Gaetano Assanto