Ustoglu Unal, V. | Aksahin, E. | Aytekin, O.

Article | 2013 | Physica E: Low-Dimensional Systems and Nanostructures47 , pp.103 - 108

The effect of an applied static field is studied on the optical properties of a quantum well (QW) represented by a Modified Pöschl-Teller potential. This potential allows analytical solution of the eigen-values and eigen-functions which in turn makes the numerical calculation of optical properties quite transparent. In this work, we concentrate on the linear and nonlinear refractive index changes. Comparison of the results using the finite Modified-Pöschl-Teller (MPT) potential with those in the literature using the infinite Pöschl-Teller (PT) potential shows that the main difference between the two potentials is coming from the dep . . .th differences of the two wells. The changes in the refractive indices are bigger than those using infinite PT potential. If one wants a larger change in the total refractive index, one should try to reduce the applied electric fields and the optical intensities. © 2012 Elsevier B.V. All rights reserved Daha fazlası Daha az

E. Aksahin | V. Ustoglu Unal | M. Tomak

Article | 2015 | Physica E: Low-Dimensional Systems and Nanostructures74 , pp.258 - 263

Abstract The nonlinear optical properties of an exciton in a spherical quantum dot (QD) is studied analytically. The nonlinear optical coefficients are calculated within the density matrix formalism. The electronic problem is solved within the effective mass approximation. The contributions from the competing effects of the confinement, the Coulomb interaction, and the applied electric field are calculated and compared with each other. We have made no assumptions about the strength of the confinement. We concentrate the effect of the Coulomb interaction. Our results may provide an input for optimization of the nonlinear optical coef . . .ficients. © 2015 Published by Elsevier B.V Daha fazlası Daha az

Aytekin, O. | Turgut, S. | Üstoglu Ünal, V. | Akşahin, E. | Tomak, M.

Article | 2013 | Physica E: Low-Dimensional Systems and Nanostructures54 , pp.257 - 261

A theoretical study of the effect of the confining potential on the nonlinear optical properties of two dimensional quantum dots is performed. A three-parameter Woods-Saxon potential is used within the density matrix formalism. The control of confinement by three parameters and an applied electric field gives one quite an advantage in studying their effects on the nonlinear properties. The coefficients investigated include the optical rectification, second and third-harmonic generation and the change in the refractive index. Their dependence on the electric field values, dot size and the energy of the incoming photons is studied ext . . .ensively. It is shown that the Woods-Saxon potential can be used to model the confinement in quantum dots with considerable success. © 2013 Elsevier B.V Daha fazlası Daha az