Yazar "Salman Durmuşlar, Aysevil" seçeneğine göre listele

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    Effect of Razavy potential well parameters on the optical rectification, second, and third harmonic generation coefficients of Razavy quantum well in the presence of electric, magnetic, and THz laser fields
    (2022) Salman Durmuşlar, Aysevil; John Peter, A.; Ungan, Fatih
    The paper presents the nonlinear optical rectification, second and third harmonic generation properties of a quantum well-formed within AlGaAs/GaAs heterostructures under the Razavy potential function. The effects of well parameters as well as applied external fields such as electric, magnetic, and non-resonant intense laser on these parameters are examined. The energies of sub-bands and dipole moment matrix elements related to wave function probabilities are obtained by solving the Schrödinger equation within effective mass and parabolic band approximations. Optical coefficients are calculated in the framework of the density matrix approach. The findings point out that the potential distribution parameters strongly affect the magnitudes as well as the locations of nonlinear optical rectification, second and third harmonic generation peaks on the corresponding incident photon energies. Besides the influences of potential parameters, subjecting the system to intense laser field leads noticeable changes on the NOR, SHG, and THG coefficients. However the changes on these properties are quite slight when the system subjected to the external electric or magnetic field. Razavy potential parameters are more effective in controlling the optical properties in comparison to the electric and magnetic field perturbations.
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    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.
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    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.
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    Theoretical simulation of optical absorption coefficients in heterostructure based on semi-parabolic-double quantum wells
    (2022) Dakhlaoui, H.; Salman Durmuşlar, Aysevil; Rodriguez-vargas, I.; Ungan, Fatih
    In this work, we have performed a numerical calculation to obtain the lowest three electron subband energy levels and their density of probabilities in a n-doped heterostructure constituted by double semi parabolic quantum wells separated by square quantum well and surrounded by two outer barriers. The numerical investigation is carried out within the framework of the parabolic single band and effective mass approximations. Firstly, we have solved self-consistently the coupled Schrödinger and Poisson equations and have determined the electronic wave functions and subband energy levels. After that we have deduced the different contributions of the optical absorptions between the lowest three electron subband energy levels. The energy variations and the occupancy ratios are also discussed to show their accordance with the behavior of the total optical absorption coefficient. Throughout this study, two cases of doping were treated. The first one is a doping in the outer barriers and the second one was a doping in the inner barriers. The doping consists of inserting 1 nm of silicon layer in the middle of the barriers. The responses of different total optical absorption coefficients, subband energy levels and confining potential by increasing the concentration of the delta-doped layers are demonstrated and the two behaviors (red and blue shifted) are discussed in detail.