Spontaneous Emission Decay of a Two-level Atom in a Structure with Modified Density of Spectrum

Xiangqian Jiang, B. Zhang, Zhenzhong Lu +1 more

The spontaneous emission spectrum of a three-level $\ensuremath{\Lambda}$-type atom driven by a microwave field was studied. For the two transitions coupled to the same modified reservoir, we discussed the influence of photonic band gap and Rabi frequency of the microwave field on the emission spectrum. The emission spectrum is given for different locations of the upper band-edge frequency. With the transition frequencies moving from outside the band gap to inside, the number of peaks decreases in the emission spectrum and the multipeak structure of spectral line is finally replaced by a strong non-Lorentzian shape. With increase of the Rabi frequency of the microwave field, we find the spectral line changes from a multipeak structure to a two-peak structure, originating from the inhibition of spontaneous emission for the corresponding decay channel.

Vladimír Bužek

G M Teka

Gao‐xiang Li, Jörg Evers, Christoph H. Keitel

We 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 states, the atom is driven by a coherent intense low-frequency field (LFF), which creates additional multiphoton decay channels with the exchange of two low-frequency photons and one spontaneous photon during an atomic transition. Due to the low frequency of the applied field, the various transition pathways may interfere with each other and thus give rise to a modified system dynamics. We find that even if all the atomic (bare and induced) transition frequencies are in the conducting band of the photonic crystal, there still may exist a photon–atom bound state in coexistence with propagating modes. The system also allows us to generate narrow lines in the spontaneous-emission spectrum. This spectrum is a function of the distance of the observer from the atom due to the band gap in the photonic crystal. The system properties depend on three characteristic frequencies, which are influenced by quantum interference effects. Thus these results can be attributed to a combination of interference and band-gap effects.

Nian-Hua Liu

The memory function of non-Markovian spontaneous emission decay process is investigated.We obtained the non-Markovian memory function and the reservoir coupling spectrum of a two-level atom embedded in a sandwich structure by the means of quantum optics.Because the modes interact with different weights to the atom,a weight factor is considered in the spectrum.As the emission field is perturbed by the sandwich structure,some pulse-like oscillations occur in memory function.The memory function is related to the Fourier transform of the spectrum,thus the wider spectrum leads to the shorter memory time.

H. J. Carmichael