Yazar "Mora-Ramos, Miguel Eduardo" seçeneğine göre listele

Listeleniyor 1 - 8 / 8
  • Küçük Resim
    Öğe
    Effects of external fields on the nonlinear optical properties of an n-type quadruple ?-doped GaAs quantum wells
    (2022) Salman Durmuşlar, Aysevil; Dakhlaoui, H.; Mora-Ramos, Miguel Eduardo; Ungan, Fatih
    Linear, third-order, total optical absorption and relative refractive index change coefficients are investigated for an ntype δ-doped GaAs/AlxGa1−xAs quadruple quantum well with electric, magnetic as well as laser fields as external probes. The Hamiltonian operator of the quaternary δ-dopedwell iswritten with the inclusion of laser dressed potential term and electric, magnetic field energy operators, in order to obtain the electronic spectrum. Optical properties are calculated by obtained electronic states within the framework of compact density matrix approach. The results show that, in the presence of external electric, magnetic and intense laser fields, the evaluated optical coefficients exhibit similar shifting characteristic with different peak magnitude variations. These findings in the optical properties of quadruple δ-doped quantum wells in the presence of external fields may provide guidance to the practical studies.
  • Küçük Resim Yok
    Öğe
    Exploring the Nonlinear Optical Behaviour of InGaAs/GaAs Triple Quantum Wells via Structural Modulations and External Electric Fields
    (Iranian Nano Society, 2023) Sayrac, Muhammed; Dakhlaoui, Hassen; Mora-Ramos, Miguel Eduardo; Ungan, Fatih
    The nonlinear optical properties of the InxGa1-xAs/GaAs triple quantum well structure are studied for different structure parameters and applied external electric field. Within the framework of the effective mass and envelope function approximations, the one-dimensional time-independent Schrödinger wave equation is solved using the diagonalization method to obtain the energy eigenvalues and eigenfunctions of the structure. The coefficients of nonlinear optical properties such as nonlinear optical rectification (NOR), second harmonic generation (SHG), and third harmonic generation (THG) of the structure are numerically evaluated from the corresponding expressions derived within the compact density matrix approximation. The influence of adjustable structure parameters and the applied external electric field affects the separation of subband energy levels and the magnitudes of dipole moment matrix elements. These changes in the electronic properties of the structure cause the NOR, SHG, and THG peak positions to shift towards lower or higher energy regions. It is expected that these results will enable the appropriate design of new optoelectronic devices. © (2023), (Iranian Nano Society). All Rights Reserved.
  • Küçük Resim
    Öğe
    Intense terahertz laser field induced electro-magneto-donor impurity associated photoionization cross-section in Gaussian quantum wires
    (2022) John Peter, A.; Mora-Ramos, Miguel Eduardo; Ungan, Fatih
    Using expressions derived within the compact density matrix approach, the peaks of optical absorption and the changes of refractive index of a hydrogenic impurity in a GaAs/GaAlAs Gaussian quantum well wire are calculated taking into account the influence of static electric, magnetic and intense laser fields. The photoionization cross section, with normalized photon energy, is computed for different values of static electric field, magnetic field, and laser dressing parameter. The dipole moment matrix elements and the transition energy between ground and first excited state energy levels are computed as functions of quantum wire width and confinement potential depth, with and without external perturbations. Donor impurity binding energy is investigated in presence of the aforementioned electromagnetic probes, using parabolic band and effective mass approximations. The results show that the absorption coefficients depend on the transition energy difference between initial and final states involved as well as on the corresponding polarization response via dipole matrix elements. Discussed optical properties are field-sensitive and they can be tuned within the desired energy ranges using these external perturbations.
  • Küçük Resim Yok
    Öğe
    Investigation of the Structural and Thermodynamic Parameters on the Nonlinear Optical Properties of InGaAs/InP Triple Quantum Well Exposed to an External Electric Field
    (Iranian Nano Society, 2023) Sayrac, Muhammed; Dakhlaoui, Hassen; Mora-Ramos, Miguel Eduardo; Ungan, Fatih
    In this study, the effects of both tunable physical parameters and thermodynamic variables on the linear and nonlinear optical properties of the InGaAs/InP triple quantum well are theoretically investigated in detail. In addition, the effect of an external static electric field applied parallel to the growth direction of the structure was also studied. To carry out this analysis, firstly, the energy eigenvalues and eigenfunctions of the system were obtained as a result of solving the time-independent Schrödinger equation using the diagonalization method, under the effective mass and envelope function approach. Then, using these energy eigenvalues and eigenfunctions, the nonlinear optical properties of the structure were calculated from the expressions derived within the compact density matrix approach via the iterative method. The effect of adjustable structure parameters and applied external fields affects the difference in subband energy levels at which transitions occur and the magnitudes of the dipole moment matrix elements. These changes in the electronic properties of the structure cause the peak positions of the total (linear plus nonlinear) optical absorption coefficient and total relative refractive index change coefficient (RRIC) to shift towards lower or higher energy regions. These results are expected to enable the proper design of new optoelectronic devices. © (2023), (Iranian Nano Society). All Rights Reserved.
  • Küçük Resim
    Öğe
    The non-resonant intense laser field effects on the binding energies and the nonlinear optical properties of a donor impurity in Rosen– Morse quantum well
    (2022) Salman Durmuşlar, Aysevil; Türkoglu, Aslan; Mora-Ramos, Miguel Eduardo; Ungan, Fatih
    We analyze the influence of electron–donor impurity interaction as well as of a high-frequency non-resonant intense laser field on the intraband linear, third-order nonlinear, and total optical absorption coefficients in a GaAs/GaAlAs heterostructure with conduction band Rosen–Morse potential profile. For this, firstly, the binding energies associated with ground and first excited states (1s, 2s) of a hydrogenic donor center have been calculated as functions of the impurity position using the effective-mass approximation and a variational procedure. Then, the linear, third-order nonlinear, and total optical absorption coefficients were evaluated for transitions between the impurity and subband electronic states. Emphasis is made on understanding the role of structure parameters on the features of these nonlinear optical properties. The numerical results show that the impurity binding energies and lowest intersubband transitions depend strongly on the high-frequency intense laser field. The presence of impurity atom causes a blueshift in the optical spectrum and an increase in the amplitude of absorption coefficients. Additionally, it was observed that studied optical transitions are sensitive to the structure parameters and high-frequency intense laser field, thus affecting the optical absorption response.
  • Küçük Resim
    Öğe
    The nonlinear optical properties of GaAs/GaAlAs triple quantum well: Role of the electromagnetic fields and structural parameters
    (2022) Tüzemen, A. T.; Dakhlaoui, H.; Mora-Ramos, Miguel Eduardo; Ungan, Fatih
    Being relevant to the field of device applications, multiple semiconductor quantum wells are systems that exhibit remarkable optical and electronic properties. These can be properly tuned by suitably modifying the composition, structural parameters, and the application of external probes. Here, the electronic and optical properties of a GaAs/GaAlAs triple quantum well have been investigated under the influence of applied electric and magnetic fields, as well as the change of well and barrier widths. We have used the diagonalization method to numerically solve the Schr¨odinger equation under the effective mass approximation for obtaining the subband energy levels and related electronic wave functions. The expressions used for evaluating linear, third-order nonlinear, and total optical absorption coefficients (TOACs) and relative refractive index changes (RRICs) were previously derived within the compact density matrix method. According to our results, whilst an increment in the applied electric field causes a red shift in TOACs and RRICs, a blue shift of the optical responses occurs with increasing the applied magnetic field. Besides, a blue shift is observed as well by changing the width of the central well (LwL), whilst a red shift is noticed when changing left and right wells (LwL and LwR) and barrier (LbL and LbR) widths for zero fields. We believe that our study could make a contribution to designing new quantum-well-based optoelectronic devices.
  • Küçük Resim
    Öğe
    The nonlinear optical rectification, second and third harmonic generation coefficients of Konwent potential quantum wells
    (2022) Sayraç, Muhammed; Martinez-Orozco, Juan Carlos; Mora-Ramos, Miguel Eduardo; Ungan, Fatih
    We have theoretically investigated the effect of structure parameters and applied external fields on the Ga1−xAlxAs/GaAs Konwent quantum well structure. Results of theoretical simulation have clarified the impact of applied external electric and magnetic fields, non-resonant intense laser field, as well as of the change in structure parameters, on the nonlinear optical rectification (NOR), second harmonic generation (SHG), and third harmonic generation (THG) in quantum wells with the Konwent potential. To evaluate these coefficients, we have solved the Schrödinger wave equation using the diagonalization method within the framework of the effective mass and single parabolic band approximations.Wave functions and the subband energy levels for the lowest bounded four states confined within the structure have been obtained. Then, NOR, SHG, and THG coefficient expression have been evaluated as functions of the incident photon energy. It is concluded that the appropriate choice of structure parameters and applied external fields could control the nonlinear optical properties of the Konwent potential quantum wells. The energy levels and the corresponding wavefunctions change with the applied external fields. The energy level change results in the shift of the peak position while the wavefunction change causes the variation in the dipole moment matrix elements, which affect the amplitude of the resonant peaks.
  • Küçük Resim Yok
    Öğe
    Role of external fields on the nonlinear optical properties of a n-type asymmetric ?-doped double quantum well
    (Springer, 2020) Salman Durmuslar, Aysevil; Mora-Ramos, Miguel Eduardo; Ungan, Fatih
    The effects of in-growth applied electric fields and in-plane (x-oriented) magnetic fields on the nonlinear optical rectification (NOR), second harmonic generation (SHG) and third harmonic generation (THG) of n-type asymmetric double delta-doped GaAs quantum well are theoretically investigated. One-dimensional Schrodinger equation is solved by considering effective mass and parabolic band approximations to obtain subband energy levels and their related wave functions. The variations in the NOR, SHG and THG coefficients are determined by using the iterative solutions of the compact density matrix approach. Obtained results indicate that the applied electric field leads to optical red-shift on NOR, SHG and THG coefficients while the magnetic field causes optical blue-shift on that coefficients. Hence we can conclude that applied electromagnetic fields can be used to tune optical properties of devices working within the region of infrared electromagnetic spectrum.