Yazar "Rodriguez-Magdaleno, K. A." seçeneğine göre listele

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    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.
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    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.
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    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.
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    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.
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    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.