Investigation of a point-like and plane-wave excitation in 2D photonic bandgap microcavities using Green’s function method

We report on a new model for simulating wave propagation in two-dimensional photonic crystals (PhCs) by means of Green’s functions rearranged to fit on the geometrical and physical properties of the structure under investigation. The model can take into account physical effects occurring when the PhC is excited by either a point-like source, for the analysis of extended crystals with line and point defects, or a plane wave coming from infinite, to investigate mirrors and microlenses. The model has been used for studying a Fabry–Peròt cavity to evaluate its response in presence of a Hankel source or a plane wave excitation. A parametric investigation of the filter response as a function of the cavity length has been carried out and the best conditions to obtain an increase of quality factor of each resonant cavity mode have been determined.