We investigate the nonlinear optical rectification (NOR) of spherical quantum dots (QDs) under Hulthén plus Hellmann confining potential with the external tuning elements. Energy and wavefunction are determined by using the Nikiforov–Uvarov method. Expression for the NOR coefficient is derived by the density matrix theory. The results show that the applied external elements and internal parameters of this system have a strong influence on intraband nonlinear optical properties. It is hopeful that this tuning of the nonlinear optical properties of GaAs/Ga1–x Al x As QDs can make a greater contribution to preparation of new functional optical devices.
We investigate the nonlinear optical rectification (NOR) of spherical quantum dots (QDs) under Hulthén plus Hellmann confining potential with the external tuning elements. Energy and wavefunction are determined by using the Nikiforov–Uvarov method. Expression for the NOR coefficient is derived by the density matrix theory. The results show that the applied external elements and internal parameters of this system have a strong influence on intraband nonlinear optical properties. It is hopeful that this tuning of the nonlinear optical properties of GaAs/Ga1–x Al x As QDs can make a greater contribution to preparation of new functional optical devices.
The effects of quantum dot (QD) radius, incident light intensity, temperature and other factors on the optical absorption coefficients (OACs) of cylindrical QDs are investigated numerically for typical GaAs/Ga[Formula: see text]Al[Formula: see text]As. We theoretically studied the cylindrical QDs with like-inversely quadratic Hellmann potential and parabolic potential. The expressions for the energy levels and wave functions were obtained by the Nikiforov–Uvarov method, and then the expressions for the OACs were derived by using the density matrix theory and the iterative method. Finally, the results show that the structural and external parameters affect the sensitivity of the optical absorption properties by influencing the matrix elements and energy levels, and the quantum confinement effects affect their applicable frequencies, which makes the QD system easier to tune.
The study presents results of the linear and non-linear optical properties of GaAs quantum dots. The reported work aims to provide new results of the quantum dot optical properties confined in Hua plus modified Eckart (HPME) potential. To obtain analytical expressions for the energy eigenvalues and the wave functions, we solved the time-independent Schrödinger equation for the HPME potential by using the parametric Nikiforov-Uvarov (NU) method. Investigation of the linear, third-order nonlinear, and total absorption coefficients and refractive index changes was done with the help of the density matrix approach. The results showed that the energy decreases in a linear manner as the potential parameter, V0. Also, it is observed that as the barrier slope increases, the peaks of the linear, third-order linear, and total absorption coefficient tend to higher values of energy. Furthermore, as the barrier slope increases, the change in refractive indices increases, and their positions shift to higher energies. Additionally, an increase in the structure parameters and optical intensity greatly influences the absorption coefficients and the refractive index changes of the quantum dots.
Abstract This paper systematically explores the third-order nonlinear optical properties and modulation mechanisms of a spherical quantum dot system confined by a Mie-type potential. We analytically solve the Schrödinger equation with Nikiforov–Uvarov method based on effective mass approximation to obtain the eigenenergies and wave function of the system. Subsequently, key third-order nonlinear optical parameters, including the third-harmonic generation (THG) coefficient, total optical absorption coefficients, and refractive index changes, are derived via the density matrix formalism. The results indicate that the nonlinear optical responses strongly depend on the geometric dimensions and the microscopic confinement parameters. By adjusting these parameters, effective control over the THG coefficient can be achieved. Furthermore, this study reveals the significant modulation effects of environmental factors. The synergistic influence of quantum dot size, confinement potential, and environmental interactions is systematically analyzed, providing a theoretical basis for designing high-performance nonlinear optical devices based on quantum dots.
The optical properties of quantum dots (QDs) in modified Möbius squared (MMS) potential are studied. To obtain the energy expressions and the wave functions, we solved the Schrödinger equation by using Nikiforov-Uvarov (NU) method. We investigated the linear, third-order nonlinear and total absorption coefficients (AC) and refractive index changes (RIC) using the density matrix. The numerical results show that the structure parameters and optical intensity have a strong influence on AC and RIC.
Abstract In this paper, the effects of external electric, magnetic and non-resonant intense laser fields on the nonlinear optical rectification (NOR), second-harmonic (SH), and third-harmonic (TH) generation in a GaAs quantum well with asymmetrical Gaussian potential are theoretically investigated. Firstly, the energy eigenvalues and eigenfunctions of a single electron confined in the structure are obtained by using the diagonalization method within the framework of the effective-mass and parabolic band approaches. Then, using these energy eigenvalues and eigenfunctions, expressions derived within the compact density matrix approximation has been employed to calculate the coefficients of the nonlinear optical response in the structure. The obtained simulation results show that the influence of the external fields leads to significant changes in the coefficients of nonlinear optical rectification, second and third harmonic generation in the system. As a result, it has been seen that the amplitude and position of the peaks of nonlinear optical rectification, second and third harmonic coefficients can be controlled by changing the applied external fields.
In this paper, we have studied optical properties of spherical quantum dots by using Rosen-Morse potential. In this regard, we have first solved the Schrodinger equation and obtained energy levels and wave functions by applying Nikiforov-Uvarov (NU) method. Then, by using density matrix method, we have applied analytical expressions for the linear and third-order nonlinear absorption coefficient and refractive index changes. The results show that the total refractive index changes and the absorption coefficients increase and shift towards higher by enhancing height potential.