A simple model for analytical treatment of quantum confined Stark effect

H. J. Carmichael, Daniel F. Walls

E. Ficocelli Varracchio

Wu Wen-Guo, Jingbiao Chen

We report the long time dynamical behaviour of ac Stark effect in a simple quantum model in which two level atoms interact with quantized coherent radiation field. A new phenomenon of periodic quantum collapse and revival of the ac Stark shift of energy level due to ac Stark effect is expressed accurately by analysing the phase of transition probability amplitude. The analytic prediction is confirmed by the numerical results.

Eckehard Schöll

Electro-optical effects, such as the Franz-Keldysh effect in bulk materials or the quantum confined Stark effect in quantum well structures, lead to strong optoelectronic nonlinearities which form the basis for optical modulators and optically bistable devices. They result from a modification of the optical absorption properties by an applied electric field and are particularly pronounced in the case of low dimensional semiconductors. We review theoretical modelling and computer simulations of such optoelectronic devices in particular for ZnSe based quantum well structures, where excitonic features dominate even at room temperature. The field dependent absorption spectra are calculated by a many-body theory including the full electron-electron interaction. The transition from the quantum confined Stark effect, which is found for well widths smaller than the exciton Bohr diameter, to the Franz-Keldysh effect, which corresponds to the limit of wide wells, is studied. Optical bistability and switching is found in R-SEED and D-SEED configurations, and the optimization of the device performance is discussed.

F. Sattin

A classical model of the hydrogen atom in a static electric field is studied, basing upon the work [ Hooker A. et al, {\it Phys. Rev. A}, 55 (1997) 4609 ]. In that work the electrons are supposed to move along Kepler orbits around the nucleus, while interacting with the external field. That classical model reproduces very well the true energy shift of the linear Stark effect. The agreement with the second order effect is poor. It is shown here that the results for the quadratic Stark effect may be considerably improved if the electrons are still allowed to move along classical trajectories, but whose initial conditions are statistically sampled from a distribution resembling the quantum mechanical one.

D. T. Pegg