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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.

Theoretical studies on excitonic and optical properties of a single exciton confined in an InP/ZnS heterostructure core/shell quantum dot embedded in various dielectric environments are investigated. The energies are found with and without the inclusion of dielectric mismatch employing single band effective mass approximation using variational formulism. The solution of Poisson-Schrodinger wave equations for the attractive term between the electron and hole is carried out using a self consistent approach in the Hartree approximation. The binding energy due to an exciton and oscillator strength is found with the effect of geometrical confinement. The total absorption coefficients, the injection current density for the optical output and the corresponding threshold optical pump intensity studied in the presence of various dielectric environments are investigated in the InP/ZnS heterostructure core/shell quantum dot. The ratio of core/shell hetero-structured quantum dot radius for various values of dielectric matrices immersed is found. The results show that the obtained properties are considerably enhanced with the incorporation of dielectric environment matrices immersed in the core/shell quantum dot particularly the highest dielectric constant will bring out the better results. It is hoped that to the present study will contribute the understanding of excitonic and optical properties in the group II–VI core/shell heterostructure quantum dots for the potential applications in photovoltaic and light emitting diodes.

Effects of laser field on electromagnetically induced transparency is investigated in a GaAs/InAs/GaAs quantum well. The taken system is InAs sandwiched between GaAs semiconducting materials. The confinement potential and the well size of the quantum well are kept constant. The three atomic sub-levels are considered and the system is considered using a density matrix approach. Laser field induced intersubband electromagnetically induced transparency in the three level single quantum well is discussed theoretically. Laser field related optical susceptibilities, Rabi frequency and the detuning parameters are computed in the present work. The variation of real and imaginary parts of optical susceptibility as a function of normalized detuning, in the influence of laser field, is obtained. The refractive index and the group velocity of the probe light pulse are found in the presence of laser field intensity. The variation of group index as a function of probe field energy, with the application of laser field, is reported. For the five units of laser parameter, the reduction of Δp∕Ωc value is found to be 0.0762. The laser field dependence on the optical susceptibilities on the normalized detuning, refractive index and the group index is brought out.

Effect of intense high frequency laser field on the electronic and optical properties of heavy hole exciton in an InAsP/InP quantum well wire is investigated taking into consideration of the spatial confinement. Laser field induced exciton binding energies, optical band gap, oscillator strength and the optical gain in the InAs0.8P0.2/InP quantum well wire are studied. The variational formulism is applied to find the respective energies. The laser field induced optical properties are studied. The optical gain as a function of photon energy, in the InAs0.8P0.2/InP quantum wire, is obtained in the presence of intense laser field. The compact density matrix method is employed to obtain the optical gain. The results show that the 1.55 μm wavelength for the fibre optic telecommunication applications is achieved for 45 A wire radius in the absence of laser field intensity whereas the 1.55 μm wavelength is obtained for 40 A if the amplitude of the laser field amplitude parameter is 50 A. The characterizing wavelength for telecommunication network is optimized when the intense laser field is applied for the system. It is hoped that the obtained optical gain in the group III-V narrow quantum wire can be applied for fabricating laser sources for achieving the preferred telecommunication wavelength.

The spin dependent electron transmission phenomenon in a diluted resonant semiconductor heterostructure is employed theoretically to investigate the output transmission current polarization at zero magnetic field. Transparency of electron transmission is calculated as a function of electron energy and the well width, within the one electron band approximation along with the spin orbit interaction. Enhanced spin-polarized resonant tunneling in the heterostructure due to Dresselhaus and Rashba spin-orbit coupling induced splitting of the resonant level is observed. We predict that a spin-polarized current spontaneously emerges in this heterostructure and we estimate theoretically that the polarization can reach 40%. This effect could be employed in the fabrication of spin filters, spin injectors and detectors based on non-magnetic semiconductors.

Exciton binding energies as a function of core/shell radius ratio are studied for the InP/ZnS core/shell quantum dot and ZnS/InP inverted core/shell quantum dot theoretically. The self-interaction potential due to the interaction between the exciton and its image charge and the built-in internal fields between inner and outer core materials are included in the Hamiltonian. The optical nonlinear susceptibilities for the second-harmonic generation and the third-harmonic generation with the photon energy for a constant radius are obtained for the core/shell and inverted core/shell quantum dots. The third-order Kerr effect as a function of photon energy is found for core/shell and inverted core/shell quantum dots of InP/ZnS and ZnS/InP semiconductors, respectively. The Kerr effect is studied using the real part of the third-order optical susceptibility.