Transient gain in photonic crystals

Kazuaki Sakoda

Xu Xing-Sheng, Chen Hong-Da

We study the transient behaviour of an external field induced transient emission of three-level atomic systems embedded in a photonic crystal with a pseudogap. The expressions for fluorescence spectra and emission dynamics for luminescent materials in the pseudogap are obtained. The properties of the transient gain in the pseudogap are discussed. It shows that the transient emission in the pseudogap can be effectively controlled.

Thomas Møller Søndergaard

XS Xu, By Cheng, Zhang Dz

Using the response formula of photonic crystals and Bloch equations, we analyzed the coherent emission in a two-level atom embedded in an arbitrary photonic crystal. We derived a formula for the transient emission expressed by the photon density of states (DOS), the Rabi frequency, and the background decay. Near the band edge, when the ratio of the Rabi frequency to the decay rate is a proper value, a transient gain occurs and the sharp structures of the DOS near the band edge lead to a drastic enhancement of the emission and the oscillation of the emission.

杜春光, 胡正峰

Without using the weak-field approximation,we investigate the transient properties of a Λ-type atom with one transition near resonant with a photonic bandgap edge.Whatever the initial state of the atom is,the atom can become transparent to a probe field,and strong gain without population inversion is also possible if the atom has been pre-excited.The defect mode formed by atomic doping can have a strong effect on the absorption properties of the atom.

Mikhail Boroditsky