The Properties Of Atomic Spontaneous Emission In Photonic Crystals

Spontaneous emission has turned out to be one of the most severe limiting factors for the storage and processing of quantum information, high frequency lasers, high precision measurement, and many other novel discoveries in modern quantum optics. An important interest of modern quantum optics is to devise ways to modify and control the spontaneous emission through the mechanism of quantum interference, and the study of spontaneous emission in photonic crystals is important one of it. Photonic crystals are artificially created periodic dielectric structures. Photonic crystals have many novel physical properties which provide a good way to control the movement of photons.The spontaneous emission of a four-level atom embedded in a one-dimensional photonic crystal is investigated. The atom has two upper levels coupled by the same vacuum modes to a common lower level and is driven by a coherent field to an auxiliary level. Spontaneous emission can be suppressed significantly due to the combinational influences of the interference effect and the band edge effect. The radiation field emitted by the atom is also studied. Spontaneous emission can be modified through controlling the Rabi frequency of the driving field.We also investigate the spontaneous emission properties of a two-level atom embedded in a three-dimensional anisotropic photonic crystal. In addition to the modified density of state, the atom is driven by a coherent intense low-frequency field, which creates additional decay channels with the exchange of one spontaneous photon during an atomic transition. Due to the low-frequency of applied field, the various transition pathways may interfere with each other and the band edge effect exists, Spontaneous emission can be suppressed significantly. The atomic population is related to the relative position of the upper levels from the band edge, the frequency of the low-frequency field and the relative intensity between the coupling strengths for transitions. Because of no singularity in the density of states, the characteristics of the spontaneous emis-sion is considerably different from what is obtained in photonic crystals with one-dimensional isotropic dispersion relation. We find the localized field can disappear and the diffusion field can become intense in some regions.