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We investigate switching response for an Optical Bistable (OB) device consisting of homogeneously broadened two-level atoms in a ring cavity supported by a Kerr Nonlinear Blackbody (KNB) radiation reservoir in the high-Q cavity regime for both absorptive and dispersive cases. In the resonant case and below a transition temperature, faster switching processes for OB devices with KNB can be triggered by a small perturbation of the incident field in the vicinity of the critical transition point. The switching time increases with increasing atomic detuning parameter. A thermal switching process is obtained for a fixed incident field and is triggered by small perturbation in the relative reservoir temperature, T b say. The switching time is reduced considerably by slightly increasing the temperature T b . Comparison with other cases of radiation reservoir is made, namely, normal, thermal and squeezed vacuum. [ABSTRACT FROM AUTHOR]

The steady state bistable behaviour of a three-level Λ-shape is examined in the presence of a control field $({\rm \Omega} +\chi \left( t\right) e^{i\varphi})$ : Ω is the strong Rabi component, $\chi \left( t\right) $ is the stochastic part with relative phase ϕ; with quantum interference between decay channels taken into account. One- and two-way phase switching effect for the transmitted field against the phase are predicted at fixed values for the incident input field. Also cooperative switching effect shows multistable/bistable behaviour. Quantum interference tends to diminish the dispersive effects responsible for multistable behaviour (in the input-output relation and the cooperative switching diagram) and asymmetry (in the phase switching diagram). Equivalence of the role of the stochastic part of the control field with that of the “classically” squeezed field is shown to occur only in the absence of quantum interference. [ABSTRACT FROM AUTHOR]

Abstract: In the present communication we investigate the usual Jaynes–Cummings Hamiltonian model, describing two-level atom interacting with an electromagnetic field, in the presence of the second harmonic generation (degenerate parametric amplifier). Exact solutions of the wave function in the Schrödinger picture have been obtained for two different cases. In the first case the field frequency ω is not equal to the splitting photon frequency ε, where the canonical transformation has been invoked to obtain the solution of the wave function. In the second case, we considered both frequencies are equal (ε=ω) and the system is taken to be at exact resonance. Both solutions have been used to discuss the atomic inversion as well as the entropy squeezing. It has been shown that the system is sensitive to any change in the coupling parameter responses of the second harmonic generation as well as to the atomic phase angle. [Copyright &y& Elsevier]