Fatih Ungan

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Nicole Herbots

Arizona State University

M. Reza Dousti

Universidade Federal Rural de Pernambuco

Adebayo D Agunbiade

Olabisi Onabanjo University, Ago-Iwoye, Nigeria

Khaled Dine

University of Dr moulay taher

Arunkumar Paulraj

Chonnam National University

Nikos Mantzakouras

National & Kapodistrian University of Athens

María Cecilia Tomasini

Universidad de Buenos Aires

SELVIN YESILAY

Princeton University

Franz Giessibl

University of Regensburg

Airán Ródenas

Universidad de La Laguna

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Papers by Fatih Ungan

Fibonacci hyperbolic quantum wells: a model for two-level non-linear optical response

Optical and Quantum Electronics

$Research paper thumbnail of The effect of impurity position and doping concentration on the binding energies and total optical absorption coefficients in a $${\delta }$$-doped quantum well$

The effect of impurity position and doping concentration on the binding energies and total optical absorption coefficients in a $${\delta }$$-doped quantum well

The European Physical Journal Plus

In this present work, for different impurity position and ionized doping concentrations, we have ... more In this present work, for different impurity position and ionized doping concentrations, we have theoretically investigated the linear, third-order nonlinear, and total optical absorption coefficients corresponding to the $$(1\rightarrow 2)$$ intersubband transitions between the ground and first-excited conduction band states in a single $$\delta $$ -doped GaAs well, with and without the presence of a donor impurity. Impurity binding energies were calculated using the effective-mass and parabolic band approximations within a variational scheme. The linear, third-order nonlinear, and total optical absorption coefficients for the intersubband transitions are calculated within the compact density matrix approach. The obtained results show that adding an impurity positioned at the symmetry center of the well, as well as the increase in the ionized donor concentrations, shifts the total optical absorption coefficients to higher photon energies. However, the off-center positions of impurities together with the varying ionized donor concentrations lead to blue or red shifts in relation to the values of binding energies. The results in this study may be useful for the design and applications of the devices based on the $$\delta $$ -doped structures.

$Research paper thumbnail of Role of external fields on the nonlinear optical properties of a n-type asymmetric $$\delta$$-doped double quantum well$

Role of external fields on the nonlinear optical properties of a n-type asymmetric $$\delta$$-doped double quantum well

Optical and Quantum Electronics, 2020

The effects of in-growth applied electric fields and in-plane (x-oriented) magnetic fields on the... more 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.

Electron-related nonlinear optical properties of cylindrical quantum dot with the Rosen–Morse axial potential

Communications in Theoretical Physics, 2020

We present a theoretical study on the effects of intense laser field (ILF) and static electric fi... more We present a theoretical study on the effects of intense laser field (ILF) and static electric field on the linear and nonlinear optical properties of a cylindrical quantum dot with Rosen–Morse axial potential under the framework of effective mass and parabolic band approximations. This study also takes into account the effects of the structure parameters (η, V1, and R). The analytical expressions of the linear, third-order nonlinear and total optical absorption coefficients (TOACs) and the relative refractive index changes (RRICs) are obtained by using the compact-density-matrix approach. The results of numerical calculations show that the resonant peak position of the TOACs and RRICs shifts towards lower energies and the magnitude of the peak increases with the effect of the static electric field and ILF. In addition, it is observed that while the resonant energies of the TOACs and RRICs of system shift towards the higher (lower) energies with the enhancement of η, V1, they decrease with the augmentation of R. Thus, the findings of this study show that the optical properties of the structure can be adjusted by changing the magnitude of structure parameters and applied external fields.

Optik, 2019

In the present work, a detailed investigation of the influence of external perturbations, in part... more In the present work, a detailed investigation of the influence of external perturbations, in particular intense terahertz radiation, static electric and magnetic fields on the electron-related optical responses such as total optical absorption coefficients and relative refractive index changes for a quantum well with the square tangent potential is presented. The subband energy levels and their corresponding wave functions are obtained by solving the one-electron Hamiltonian of the system under the framework of the effective-mass and parabolic band approximations. Optical coefficients are reported for varying incident photon energies. The numerical results show that the optical response is shifted towards the blue with the increase in the magnitude of the applied external fields. These results can provide an input for use in optoelectronic device applications.

Fatih Ungan

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