Confined exciton-polaritons in parabolic and Gaussian quantum wells

Abstract

In order to study the confined polaritons in gradual quantum structures we have calculated the exciton binding energies of parabolic and Gaussian quantum wells using a variational perturbative approach. In the linear regime, we have established, by means of the semi-classical theory, the dispersion modes of a polariton confined in quantum wells, where the confining potentials are parabolic and Gaussian. In fact, we have evaluated the oscillator strength of each quantum well in order to get an idea about the confinement size and we have concluded that the polariton is more confined in a Gaussian quantum well than in a parabolic quantum well. To make a complete description of the confined polariton we have taken into account the electron-hole exchange energy. Numerical results show that the largest effect arising from the exciton-radiation interaction is the ZT and LT splittings, which strongly depend on the quantum confinement.

Reflectivity of Gradual Bragg Reflectors in Semiconductor Microcavities

“…Moreover, the solution of this problem is obtained by solving numerically the full equation (4) [6]. The association of these Bragg mirrors forms a gradual DBR with a period equal to l 1 l 2 .…”

Reflectivity of Gradual Bragg Reflectors in Semiconductor Microcavities

“…Setting l 1 53X7 nm, we can know get the width l 2 from the relation (8). Moreover, the solution of this problem is obtained by solving numerically the full equation (4) [6]. The association of these Bragg mirrors forms a gradual DBR with a period equal to l 1 l 2 .…”

“…The estimated thickness of one Bragg mirror is found to be superior to 50 nm in the case of GaAs/AlAs Bragg reflectors. Experimental studies realized on some GaAs/AlAs superlattices have shown that the excitonic energies are sensitive to the interface graduality structure [5,6]. In the same way, the light propagation inside a system built from gradual Bragg mirrors is also perturbed by the quality of the interface.…”