Self-Optimization of Optical Confinement and Lasing Action in Disordered Photonic Crystals

Light scattering is usually regarded detrimental to optical confinement in conventional lasers. In contrast, in random lasers, the confinement is caused by disorder-induced scattering. In strongly scattering media, the lasing is defined by the high-quality modes of the passive system. Thus, by incorporating and optimizing a degree of order, one can dramatically reduce the threshold of a random laser to the values comparable to those of photonic crystal (PhC) lasers. Unlike the latter, where the optical cavity has to be carefully designed and impeccably fabricated, in disordered systems the modes originate from the structure imperfections unintentionally introduced during the fabrication process. Optical gain