Photonic-crystal superradiant laser: Effects of homogeneousand inhomogeneous broadening of an active medium

摘要

We investigate superradiant lasing in 1D photonic crystal taking into account both homogeneous and inhomogeneousbroadening in a two-level active medium. The latter may be based on, e.g., the quantum-well heterostructures and thefibers activated by color centers where Bragg structure can be fabricated artificially by means of a periodic modulationof the cladding layers. The truncated Maxwell-Bloch equations for the counter-propagating waves, the polarization andinversion of an inhomogeneously broadened two-level medium are used to analyze numerically the interplay between theback-scattering, amplification, dispersion, and de-phasing of waves. It is found that, if the photonic band gap is less thanthe coherent amplification bandwidth, there is a wide range of the pumping and relaxation parameters of a two-level me-dium where superradiant lasing exists and results in generation of a quasi-periodic and/or chaotic series of powerful andshort pulses similar to those of Dicke superfluorescence. It is the cavity mode selection due to distributed feedbackcaused by the resonant Bragg structure which is responsible for the existence of superradiant lasing. Typical parametersof superradiant photonic-crystal lasers, including lengths, photonic band gaps and relaxation rates, are indicated.