Light amplification in active photonic band gap structures

The paper deals with the modeling, based on the Finite Difference Time Domain method, of active two-dimensional photonic crystals. The onset of laser oscillation is observed by simulating the active substance as having a negative frequency-dependent Lorentzian-shaped conductivity so including into Maxwell's equations an electric current density. The properties of the active two-dimensional photonic band gap structures are evaluated in presence of gain saturation effects.