Enhanced light amplification due to group velocity anomaly in two-dimensional photonic crystals

Summary form only given. Photonic crystals can control the nature of radiation field. In addition to their peculiar optical properties such as suppression of spontaneous emission due to photonic band gaps, the small group velocity at band edges and so on, which will be called group-velocity anomaly hereafter, brings about the enhancement of sum-frequency generation and stimulated emission. In this paper, we will derive an analytical expression for the enhancement of light amplification and evaluate it numerically for two-dimensional crystals with finite thickness to show that an extremely large enhancement can be observed even for very thin samples.