Sparse and trapping dressed states in a quasi-continuum system

Piers Coleman, P. L. Knight

Sam Tarzi, PAUL M. RADMORE, Stephen Mark Barnett

The authors study a quasicontinuum system for which there exists a sparse dressed state composed of the ground state and a single state of the true continuum. In general, the loss of population from the ground state to a true continuum via the quasicontinuum is total. In a special case, however, population is trapped in the ground state and the sparse dressed state is replaced by a trapping state containing no contribution from the true continuum.

Piers Coleman, P. L. Knight

N. K. Rahman, A. Lami

Indranil Bayal, Bibhas Kumar Dutta, Pradipta Panchadhyayee +1 more

We have studied a photonic structure, based on a semi-classical approach, considering simultaneous interaction of two side-coupled bent waveguides having variable coupling interactions (Gaussian and exponential-type) with a dressed continuum. We have examined the condition of optical trapping in spatial domain during propagation of a light field through the waveguide. The variation in parametric conditions leading to a typical trapping (quasi-trapping) phenomenon for both the cases of exponential and Gaussian coupling interactions is discussed. Simulation of such phenomenon of trapping in our macroscopic photonic structure is possible for all even relative positions of the side waveguides coupled to the dressed continuum. As far as the onset of quasi-trapping is concerned, the coupling width in the Gaussian coupling case is smaller than that in the exponential case. In this context, the Gaussian profile is found more tolerant than the exponential one so far as the separation between the side-coupled waveguides is concerned. Perfect trapping is observed to sustain by setting proper conditions while launching initial light in the side waveguides.

Stanley L. Haan, G. S. Agarwal

Complex dressed states and photoelectron spectra are considered for a model system containing two discrete states that are coupled by separate lasers to a continuum that supports a resonance such as an autoionizing state. Spontaneous radiative decay from the structured continuum has been included and its effects are examined. It is shown that population can be trapped within the model atom even when radiative decay is included provided (1) the two Fano q values which characterize the discrete-state--continuum interactions are equal, and (2) the two-photon resonance condition is satisfied.