A general expression of emission spectrum for a two-level atom interacting with gray-body radiation field is given in this paper. We investigate how the photon-number distribution of the incident field, the absorptivity of the cavity and the temperature of the system affect the time-dependent physical spectrum.
The time-dependent two-photon emission spectra of a two-level atom interacting with a single-mode radiation field in an ideal cavity have been studied. The expressions of the system operators as a function of time have been derived based on the two-photon Jaynes-Cummings model and Heisenberg equation. As a result, the theoretical curves of the time-dependent two-photon emission spectra have been given. The features of two-photon emission spectra depend not only on the photon statistical distribution of the initial field, such as the thermal field, the squeezed vacuum field, and the coherent field, but also on the passband width of the filter detector \ensuremath{\Gamma}. The two-photon emission spectra exhibit multi- peaked structures when \ensuremath{\Gamma}(two-photon coupling constant).
The emission spectrum of a pair of two-level atoms interacting with a single mode of radiation field in an ideal cavity is investigated, where the interaction of each atom with the field may be different. A general expression for the emission spectrum is presented and the spectrum is studied numerically when the radiation field is initially in the vacuum state, pure number state and squeezed-vacuum state, respectively. The effects of the ratio of two coupling constants (R=g 2 /g 1 ) on the emission spectrum are discussed. In contrast with the spectrum of a one-atom system, the spectrum of a two-atom system is much more complicated. Generally, the emission spectrum shows a 12-peak structure for the vacuum state and 16-peak structure for the pure number state. For the squeezed-vacuum state, it is found that the Rabi splitting is most apparent when R=1.
By means of time-evolution operator,the emission spectrum of a Λ-type three-level atom interacting resonantly with two-mode thermal radiation cavity fields was studied.The physical spectrum expression of radiation emitted by the atom was given.The structure of the emission spectrum for a thermal input was discussed.The results indicate that whether two lower levels are degeneracy or not,Rabi splitting occurred in the emission spectra of Λ-type three-level atom when the average photon number of two-mode thermal radiation cavity fields is very small.And the structure of the resonant emission spectra of the atomic system has ten peaks generally.
The emission spectrum of a two-level atom interacting dispersively with a single mode radiation field in the dissipative cavity is investigated. A general expression for the emission spectrum is derived. The numerical results for the initial field in coherent state are calculated. It is found that the spectrum structure is influenced significantly by the cavity damping constant κ, and the spectrum structure is dependent on the interaction time T when the cavity dissipation is present. Only one peak located at ω a appears in the atomic spectra for larger T.
The multiphoton emission spectrum of a pair of coupling two-level atoms interacting with two modes of the radiation field is studied. A general expression for the two-mode multiphoton emission spectrum is presented. The non-degenerate two-photon emission spectra of two atoms are calculated when the two modes of the field are in various number states and some new results are obtained. It is found that the two-atom emission spectrum in the two-mode vacuum field reflects the atomic dipole-dipole interaction more sensitively than in the case of a single-mode vacuum field.