title: Lasing threshold control in two-dimensional photonic crystals with gain.
abstract: We demonstrate how the lasing threshold of a two dimensional photonic crystal containing a four-level gain medium is modified, as a result of the interplay between the group velocity and the modal reflectivity at the interface between the cavity and the exterior. Depending on their relative strength and the optical density of states, we show how the lasing threshold may be dramatically altered inside a band or, most importantly, close to the band edge. The idea is realized via self-consistent calculations based on a finite-difference time-domain method. The simulations are in good agreement with theoretical predictions.
authors.forename: Sotiris
authors.initials: S
authors.lastname: Droulias
authors.forename: Chris
authors.initials: C
authors.lastname: Fietz
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Thomas
authors.initials: T
authors.lastname: Koschny
authors.forename: Costas M
authors.initials: CM
authors.lastname: Soukoulis