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Öğe Donor impurity atom effect on the inter-subband absorption coefficient for symmetric double n-type ?-doped GaAs quantum well(Academic Press Ltd- Elsevier Science Ltd, 2021) Rodriguez-Magdaleno, K. A.; Turkoglu, A.; Ungan, F.; Mora-Ramos, M. E.; Martinez-Orozco, J. C.In this work, the electronic structure and the inter-subband absorption coefficient (IAC) are theoretically studied for symmetric double n-type delta-doped GaAs quantum well considering the donor impurity atom effect. The electron states are determined by a diagonalization procedure, working within the effective mass and parabolic band approximations, and the effect of donor center is treated via the variational method. Meanwhile, linear and nonlinear contributions for the inter-subband absorption coefficient were evaluated from expressions usually derived within the perturbative solution of the Von Neumann equation for density matrix. We report the impurity binding energy by considering a donor atom located at the center of the system (at z(i) = 0). We found that the reported physical properties become more sensitive to the inter-well separation distance L-w than to the delta-doping density, N-2d. In the former case the total optical absorption coefficient undergoes an important red-shift as well as a significant decrease in its magnitude. When N-2d values increase, the binding energy exhibits a contrary effect, and the total optical absorption coefficient exhibits an small blue-shift with no significant changes in its magnitude. The presence of the donor impurity atom in the system represents one factor that can modify the location of inter-subband absorption coefficient, by inducing a blue-shift of the optical response. The resonant peak energies are within the range of several terahertz, showing potential device applications within this range of the electromagnetic spectrum.Öğe Effect of applied electric field on the nonlinear optical properties of modulation-doped GaAs/AlxGa1-x As double quantum well(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2019) Ungan, F.; Martinez-Orozco, J. C.; Restrepo, R. L.; Mora-Ramos, M. E.; Duque, C. A.In the present study, the effects of varying doping concentration and applied electric field on the intersubband-related optical absorption and relative refractive index change coefficients in modulation-doped GaAs/AlxGa1-x As double quantum wells are theoretically investigated. The allowed energy levels and the corresponding wave-functions are calculated by solving the Schrodinger and Poisson equations self-consistently within the framework of the effective-mass and parabolic band approximations. The optical coefficients are evaluated using the compact density matrix formalism within an iterative procedure. The numerical results are presented for two different doping concentration and several values of the electric field. They show that both the peak position and the magnitude of the calculated total optical absorption coefficients and refractive index changes are significantly affected by the applied electric field and the doping concentration. The treatment is suitable to consider the general problem with different wells and barrier sizes, although the barrier width should preferably be small enough as to allow for an effective inter-well coupling.Öğe Effect of the magnetic field on the nonlinear optical rectification and second and third harmonic generation in double delta-doped GaAs quantum wells(ELSEVIER SCIENCE BV, 2017) Martinez-Orozco, J. C.; Rojas-Briseno, J. G.; Rodriguez-Magdaleno, K. A.; Rodriguez-Vargas, I.; Mora-Ramos, M. E.; Restrepo, R. L.; Ungan, F.; Kasapoglu, E.; Duque, C. A.In this paper we are reporting the computation for the Nonlinear Optical Rectification (NOR) and the Second and Third Harmonic Generation (SHG and THG) related with electronic states of asymmetric double Si-d-doped quantum well in a GaAs matrix when this is subjected to an in-plane (x-oriented) constant magnetic field effect. The work is performed in the effective mass and parabolic band approximations in order to compute the electronic structure for the system by a diagonalization procedure. The expressions for the nonlinear optical susceptibilities, chi((2))(0), chi((2))(2 omega), and chi((3))(3 omega), are those arising from the compact matrix density formulation and stand for the NOR, SHG, and THG, respectively. This asymmetric double d-doped quantum well potential profile actually exhibits nonzero NOR, SHG, and THG responses which can be easily controlled by the in-plane (x-direction) externally applied magnetic field. In particular we find that for the chosen configuration the harmonic generation is in the far-infrared/ THz region, thus and becoming suitable building blocks for photodetectors in this range of the electromagnetic spectra.Öğe Effects of electromagnetic fields on the nonlinear optical properties of CrossMaric asymmetric double quantum well under intense laser field(ELSEVIER SCIENCE BV, 2017) Yesilgul, U.; Sari, H.; Ungan, F.; Martinez-Orozco, J. C.; Restrepo, R. L.; Mora-Ramos, M. E.; Duque, C. A.; Sokmen, I.In this study, the effects of electric and magnetic fields on the optical rectification and second and third harmonic generation in asymmetric double quantum well under the intense non-resonant laser field is theoretically investigated. We calculate the optical rectification and second and third harmonic generation within the compact density -matrix approach. The theoretical findings show that the influence of electric, magnetic, and intense laser fields leads to significant changes in the coefficients of nonlinear optical rectification, second and third harmonic generation. (C) 2017 Elsevier B.V. All rights reserved.Öğe Electron Raman scattering in a double quantum well tuned by an external nonresonant intense laser field(ELSEVIER SCIENCE BV, 2017) Tiutiunnyk, A.; Mora-Ramos, M. E.; Morales, A. L.; Duque, C. M.; Restrepo, R. L.; Ungan, F.; Martinez-Orozco, J. C.; Kasapoglu, E.; Duque, C. A.In this work we shall present a study of inelastic light scattering involving inter-subband electron transitions in coupled GaAs-(Ga,AI)As quantum wells. Calculations include the electron related Raman differential cross section and Raman gain. The effects of an external nonresonant intense laser field are used in order to tune these output properties. The confined electron states will be described by means of a diagonalization procedure within the effective mass and parabolic band approximations. It is shown that the application of the intense laser field can produce values of the intersubband electron Raman gain above 400 cm(-1). The system proposed here is an alternative choice for the development of Al chi Ga1-chi As semiconductor laser diodes that can be tuned via an external nonresonant intense laser field. (C) 2017 Elsevier B.V. All rights reserved.Öğe Intermediate band formation in a delta-doped like QW superlattices of GaAs/AlxGa1-xAs for solar cell design(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2018) Del Rio-De Santiago, A.; Martinez-Orozco, J. C.; Rodriguez-Magdalen, K. A.; Contreras-Solorio, D. A.; Rodriguez-Vargas, I.; Ungan, F.It is reported a numerical computation of the local density of states for a delta-doped like QW superlattices of AlxGa1-xAs, as a possible heterostructure that, being integrated into a solar cell device design, can provide an intermediate band of allowed states to assist the absorption of photons with lower energies than that of the energy gap of the solar-cell constituent materials. This work was performed using the nearest neighbors sp(3)s* tight binding model including spin. The confining potential caused by the ionized donor impurities in delta-doped impurities seeding that was obtained analytically within the lines of the Thomas-Fermi approximation was reproduced here by the Al concentration x variation. This potential is considered as an external perturbation in the tight-binding methodology and it is included in the diagonal terms of the tight-binding Hamiltonian. Special attention is paid to the width of the intermediate band caused by the change in the considered aluminium concentration x, the inter-well distance between delta-doped like QW wells and the number of them in the superlattice. In general we can conclude that this kind of superlattices can be suitable for intermediate band formation for possible intermediate band solar cell design. (C) 2018 Elsevier Ltd. All rights reserved.Öğe Intra and interband optical absorption coefficient for asymmetric double AlGaAs/GaAs quantum well under hydrostatic pressure and electric field effects(Elsevier, 2024) Maldonado-Villa, B. E.; Rodriguez-Magdaleno, K. A.; Nava-Maldonado, F. M.; Duque, C. A.; Ungan, F.; Martinez-Orozco, J. C.In this work, we have studied the effects of hydrostatic pressure and an electric field applied along the confinement direction on the absorption coefficient for asymmetric double AlGaAs/GaAs quantum wells within the framework of the effective mass theory. The hydrostatic pressure considered ranges from 0 to 40 kbar, while the chosen electric field ranges from-25 to 30 kV/cm, yielding the most interesting results. We have reported the system's energy levels, the associated dipole matrix elements, and the inter- and intra-band absorption coefficient for the most probable transition, considering each external factor separately. We found that the hydrostatic pressure induces a significant blueshift in the interband absorption coefficient, while it induces a slight redshift in the intraband transitions. On the other hand, the electric field initially redshifts the signal, and later it becomes blue- shifted for the interband absorption coefficient, exhibiting a very similar behavior for intraband transition as the electric field changes. These results show that the hydrostatic pressure, as well as the electric field, can be used as efficient mechanisms to tune both inter and intraband optical transitions.Öğe Linear and nonlinear optical properties in an asymmetric double quantum well under intense laser field: Effects of applied electric and magnetic fields(ELSEVIER SCIENCE BV, 2016) Yesilgul, U.; Al, E. B.; Martinez-Orozco, J. C.; Restrepo, R. L.; Mora-Ramos, M. E.; Duque, C. A.; Ungan, F.; Kasapoglu, E.In the present study, the effects of electric and magnetic fields on the linear and third-order nonlinear optical absorption coefficients and relative change of the refractive index in asymmetric GaAs/GaAlAs double quantum wells under intense laser fields are theoretically investigated. The electric field is oriented along the growth direction of the heterostructure while the magnetic field is taken in-plane. The intense laser field is linear polarization along the growth direction. Our calculations are made using the effective-mass approximation and the compact density-matrix approach. Intense laser effects on the system are investigated with the use of the Floquet method with the consequent change in the confinement potential of heterostructures. Our results show that the increase of the electric and magnetic fields blue-shifts the peak positions of the total absorption coefficient and of the total refractive index while the increase of the intense laser field firstly blue-shifts the peak positions and later results in their red-shifting. (C) 2016 Elsevier B.V. All rights reserved.Öğe Nonlinear optical rectification and second-harmonic generation in a semi-parabolic quantum well under intense laser field: Effects of electric and magnetic fields(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2015) Ungan, F.; Martinez-Orozco, J. C.; Restrepo, R. L.; Mora-Ramos, M. E.; Kasapoglu, E.; Duque, C. A.The effects of electric and magnetic fields on the nonlinear optical rectification and second harmonic generation coefficients related with intersubband transitions in a semi-parabolic quantum well under intense laser field are theoretically studied. The energy levels and corresponding wave functions are obtained by solving the conduction band Schrodinger-like equation in the parabolic approximation and the envelope function approach. Numerical calculations are presented for a typical GaAs/Ga1-xAlxAs quantum well. The results show that both the non-resonant intense laser field and the static external fields have significant influences on the magnitude and resonant peak energy positions of the coefficients under study. (C) 2015 Elsevier Ltd. All rights reserved.Öğe Optical responses in asymmetric hyperbolic-type quantum wells under the effect of external electromagnetic fields(Elsevier, 2020) Ungan, F.; Bahar, M. K.; Martinez-Orozco, J. C.; Mora-Ramos, M. E.In the present work, some optical properties related to intersubband transitions in finite depth asymmetric hyperbolic-type quantum wells are theoretically investigated. The use of a hyperbolic potential configuration would account for the actual - non abrupt - confinement potential in the heterostructure, in the case of modulated growing or when compositional diffusion across the interfaces turns out to be relevant. In the investigation, the presence of externally applied electromagnetic fields is considered. Electron conduction band states are determined within the parabolic band an effective mass approximation. With the electronic structure information at hand, it is possible to evaluate the linear and third-order nonlinear light absorption and relative refractive index change coefficients, from expression arising in the framework of the compact density matrix approach. According to the theoretical outcome, it is found that: (i) There is a significant influence of the structural configuration on the magnitude and resonant peak position of the total optical coefficients. (ii) Under the effect of increasing external electric and magnetic fields, the peak energy positions are shifted towards higher values, whereas their amplitude decrease for the optical absorption case, and that of the refractive index relative variation is reduced. From these results it can be concluded that both the modification of the confinement profile and the presence of electric and/or magnetic fields are suitable tool to control the optical response of asymmetric hyperbolic-type semiconductor quantum wells.Öğe Studies on the nonlinear optical properties of two-step GaAs/Ga1-xAlxAs quantum well(Iop Publishing Ltd, 2020) Martinez-Orozco, J. C.; Ungan, F.; Rodriguez-Magdaleno, K. A.In this paper, the numerical computation for the absorption coefficient and the relative refractive index change, considering the third order correction nonlinear optical properties, is reported. This study was performed for a symmetric two-step GaAs/Ga1-xAlxAs quantum well, subjected to a constant electric field applied along the growth direction z, and an in-plane constant magnetic field B. We also consider the intense laser field effect, characterized through the laser-dressing parameter alpha(0). The electronic structure computation was obtained by working under the effective mass approximation and the Schodinger equation was solved by diagonalization procedure. The optical properties are calculated by using the well-established compact density matrix formalism expressions for the nonlinear optical properties of interest. In general, we found that the structural parameters, as the step-like potential or the central barrier, permit the resonant peak and the amplitude design. We also found that the system becomes more sensitive to electric than to magnetic field, and finally that the intense, non-resonant, laser field can strongly change the optical properties of interest. Our results indicate that the implementation of the step-like potential profile, experimentally feasible, enhance the optical properties of interest, that falls within the THz electromagnetic range, and can be used to design a photodetector, or even can be used for quantum cascade lasers design.Öğe Third harmonic generation of a 12-6 GaAs/Ga1-xAlxAs double quantum well: effect of external fields(Springer Heidelberg, 2024) Rodriguez-Magdaleno, K. A.; Demir, M.; Ungan, F.; Nava-Maldonado, F. M.; Martinez-Orozco, J. C.In this paper, we report the third harmonic generation in a 12-6 potential profile-shaped GaAs/Ga1-xAlxAs double quantum well. We investigate the effects of the well width size and the presence of the external fields: electric, magnetic, and intense laser. The electronic structure is calculated within the effective mass approximation using a diagonalization method to solve the Schrodinger equation. The expression for third harmonic generation comes from the compact density matrix method. Our results show that the intense laser field effect strongly affects the optoelectronic properties; the electric field (well width) redshifts (blueshifts) the third harmonic generation peaks. Additionally, we observe that the magnetic field has a negligible impact on the studied properties for this potential profile. It is important to stress that the optical signal is in the THz range and that these results can be considered to design possible systems for THz radiation in optoelectronic devices.
