Spectral Features of a Two-Atom Dicke Model in a Narrow Bandwidth Squeezed Bath
In recent years the successful experimental generation of squeezed light has become a significant event for the quantum optics. The peculiar nature of the squeezed electromagnetic field is that the (plantain fluctuations in one of its quadrature is less than the vacuum level but the fluctuations in the conjugate quadrature is increased as required by the uncertainty principle. Many interesting aspects of the interaction of a single two-level atom with squeezed bath have been studied1,2. These studies include the decay of polarization and population, atomic absorption spectrum. resonance fluorescence spectrum and the Lamb shift etc.. In above studies the ordinary vacuum has been replaced by a multimode squeezed vacuum. This multimode squeezed vacuum may be a broad (or infinite) bandwidth squeezed vacuum or a narrow (or finite) bandwidth squeezed vacuum. However, in both the cases there exists a strong correlation between the modes. Since the presently available squeezed light from the degenerate parametric amplifier has got finite bandwidth so it is imperative to know the effects of finite bandwidth squeezed bath on the radiative properties of the atom. Some recent studies are emphasiug that the line narrowing degrades with the finite bandwidth3. Our this study concerns with investigation of the behaviour of a collection of atoms in a finite bandwidth squeezed bath. In particular, we derive the expression of steadystate spectrum of resonance fluorescence from a system of two identical coherently driven two-level atoms interacting with a finite bandwidth squeezed bath including the atomic dipole-dipole interaction between the atoms. The dipole-dipole interaction term is known to he important in the case of the Dicke model which assumes close spacing between the atoms. Such a terni results by retaining the atomic position dependent term in the Hamiltonian and going to the limit of small systems after eliminating bath operators from the equation of density matrix2. The novelty of this work is that the characterist ics of the spectral features are studied by solving the piaster equation analytically in the limit of strong driving field. Thus the steadystate resonance fluorescence spectrum can be analyzed analytically for the different values of squeezed vacuum parameters4.
KeywordsNarrow Bandwidth Lamb Shift Peculiar Nature Finite Bandwidth Atomic Absorption Spectrum
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