Terahertz pulse generation via optical rectification in photonic crystal   microcavities
  Using a 3D fully-vectorial nonlinear time-domain analysis we numerically investigate the generation of terahertz radiation by pumping a photonic crystal microcavity out of resonance. High quality factors and a quadratic susceptibility lead to few-cycle terahertz pulses via optical rectification. Material dispersion as well as linear and nonlinear anisotropy is fully accounted for. 
Andrea Di Falco, Claudio Conti and Gaetano Assanto