双能带三维光子晶体中二能级原子的自发辐射

研究了双能带三维光子晶体中二能级原子自发辐射的性质.由于双能带各向异性色散关系的影响，辐射场中的局域场和传输场不能共存，导致原子上能级占据数不再具有准周期性振荡的性质，而是随时间趋于常数，或者随时间按幂函数形式衰减，或者随时间按指数形式衰减.这些性质不仅与原子上能级和能带带边的相对位置有关，而且与光子晶体上、下能带之间的能隙宽度有关.这些性质也有别于单能带各向同性光子晶体中二能级原子自发辐射的性质. 关键词： 光子晶体 二能级原子 自发辐射

Spontaneous emission from a two-level atom embedded in two-band three-dimensional photonic crystals

We have studied the properties of the spontaneous emission from a two-level atom embedded in two-band photonic crystals. Due to the anisotropic two-band dispersion relation, the localized and propagating fields cannot coexist, this leads to the non-quasi-oscillation behaviour of the upper level population. Thus the upper level population will tend to a constant as time goes to infinity, or decay with time in a power law, or decay with time exponentially, different from that in the isotropic one-band dispersion relation case. These properties are directly related to the relative position of the upper level from the band edge and the width of the gap.