Quantum confined stark effect in wide parabolic quantum wells: real density matrix approach

Abstract

Abstract.We show how to compute the optical functions of wide parabolic quantum wells (WPQWs) exposed to uniform electric F applied in the growth direction, in the excitonic energy region. The effect of the coherence between the electron-hole pair and the electromagnetic field of the propagating wave including the electron-hole screened Coulomb potential is adopted, and the valence band structure is taken into account in the cylindrical approximation. The role of the interaction potential and of the applied electric field, which mix the energy states according to different quantum numbers and create symmetry forbidden transitions, is stressed. We use the real density matrix approach (RDMA) and an effective e-h potential, which enable to derive analytical expressions for the WPQWs electrooptical functions. Choosing the susceptibility, we performed numerical calculations appropriate to a GaAs/GaAlAs WPQWs. We have obtained a red shift of the absorption maxima (quantum confined Stark effect), asymmetric upon the change of the direction of the applied field (F → −F), parabolic for the ground state and strongly dependent on the confinement parameters (the QWs sizes), changes in the oscillator strengths, and new peaks related to the states with different parity for electron and hole.

A Theoretical Study of Interband Absorption Spectra of Spherical Sector Quantum Dots under the Effect of a Powerful Resonant Laser

“…In 1986 [ 30 ], the split, or more particularly the exciton optical Stark effect, was identified for the first time in quantum wells. Due to its potential use in ultrafast nonlinear optical devices, such as optical gating [ 32 , 33 ] and high-speed all-optical switching [ 30 , 34 ], as well as its contribution to the understanding of the interaction between photons and semiconductors [ 35 ], this separation has received considerable theoretical and experimental attention [ 30 , 31 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ]. There are two types of separation: two-level [ 60 ] and three-level [ 60 , 61 ].…”

“…There are two types of separation: two-level [ 60 ] and three-level [ 60 , 61 ]. Several theoretical approaches, such as the renormalized wave function formulation [ 48 ], the finite difference method [ 49 ], the many-body perturbation theory [ 50 ], the photoemission theory [ 51 ], or the density matrix approach [ 52 , 53 ], have been utilized to study the separation thus far. Despite the fact that each of these methods has its own benefits, the first approach is usually used for the study of the three-level effect, since it provides a clear quantum-mechanical explanation of the phenomenon.…”

Three-Level Optical Stark Effect of Excitons in GaAs Cylindrical Quantum Wires

“…The excitonic optical Stark effect can be experimentally studied by the pump-probe technique [40,41]. For theoretical research, methods to be deployed can be the renormalized wave function theory [42], the density matrix approach [43,44], the finite difference method [45], the photoemission theory [46], or the nonequilibrium many body perturbation theory [47]. In our viewpoint, the renormalized wave function formulation has many advantages such as it only renormalizes the wave function of exciton, or it is easy to confirm the existence of the effect as well as to reveal its physical properties.…”