The effects of the electric and magnetic fields on the nonlinear optical properties in the step-like asymmetric quantum well

In the present work, total optical absorption coefficient (the linear and third-order nonlinear) and total refractive index change for transition between two first lower-lying electronic levels in the step-like GaAs/Ga1-xAlxAs quantum well under the electric and magnetic fields are investigated and also the effect of relaxation time on saturation is investigated. A compact density-matrix approach is applied to investigate optical properties. The obtained results show that both total absorption coefficient and refractive index change are sensitive to well dimensions more than external fields. With the increase of quantum well width, total absorption coefficient and refractive index change shift to lower photon energies (red shift), the magnitude of total refractive index increases significantly while total absorption coefficient is reduced. Furthermore, the electric and magnetic fields induce a blue-shift on absorption coefficient and refractive index change. (C) 2014 Elsevier B.V. All rights reserve