Theoretical Aspects of Spontaneous Photon-Emission from Atoms.

O. Zobay, G. Alber

In isolated-core excited Rydberg systems the destruction of quantum coherence by spontaneous emission of photons is investigated. For this purpose a theoretical description is developed which is based on a decomposition of the atomic density operator into N-photon contributions. Using methods from multichannel quantum defect theory, the relevant atomic transition amplitudes are represented in the form of semiclassical path representations which are associated with repeated returns of the Rydberg electron to the ionic core. Apart from numerical advantages, this approach also yields a clear physical picture of the intricate interplay between the incoherent photon emission process, the coherent laser-modified electron correlation effects, and the semiclassical aspects of the dynamics of the Rydberg electron. Various examples of this interplay are analyzed within the framework of the developed theoretical tools. \textcopyright{} 1996 The American Physical Society.

P. E. Gordon, N. M. Chase

Jiang Li, Ren-Gang Wan, Zhihai Yao

The spontaneous emission from a microwave-driven four-level atom embedded in an anisotropic photonic crystal is studied. Due to the modified density of state (DOS) in the anisotropic photonic band gap (PBG) and the coherent control induced by the coupling fields, spontaneous emission can be significantly enhanced when the position of the spontaneous emission peak gets close to the band gap edge. As a result of the closed-loop interaction between the fields and the atom, the spontaneous emission depends on the dynamically induced Autler–Townes splitting and its position relative to the PBG. Interesting phenomena, such as spectral-line suppression, enhancement and narrowing, and fluorescence quenching, appear in the spontaneous emission spectra, which are modulated by amplitudes and phases of the coherently driven fields and the effect of PBG. This theoretical study can provide us with more efficient methods to manipulate the atomic spontaneous emission.

Dmitri Smirnov, I. V. Sokolov, Evgenii Dmitrievich Trifonov

W. L. Lama, L. Mandeļ

Kai Ling, Jiang Li, Ren-Gang Wan +1 more

The spontaneous emission property of Λ-type three-level atom driven by the bichromatic field in the anisotropic double-band photonic crystal is calculated by n-times iteration method. The influence of different parameters on atomic spontaneous emission is studied, and the phenomena of atomic spontaneous emission are explained in the dressed state representation. It is found that the spontaneous emission spectra of the atom driven by the bichromatic field presents a multi-peak comb structure. The position of the emission peak is determined by the initial state of the atom, and the interval between the neighboring emission peaks is the detuning δ of the bichromatic field. When the ratio between Rabi frequency intensity and the detuning δ of the bichromatic field remains unchanged, the intensity of each emitted peak remains invariant. The spontaneously emitted peak can be annihilated in the band gap and enhanced near the band edge in the anisotropic photonic crystals. Meanwhile, we also observe the fluorescence quenching phenomenon in the spontaneous emission spectra. The research in this paper provides the theoretical guidance for the control of atomic spontaneous emission.