Linear and nonlinear optical absorption coefficients and refractive index changes with the screened cosine Kratzer potential

Linear and nonlinear optical absorption coefficients and refractive index changes in asymmetrical Gaussian potential quantum wells with applied electric field

Donor-impurity-related optical absorption and refractive index changes in GaAs/AlGaAs core/shell spherical quantum dots

Linear and nonlinear optical absorption coefficients (ACs) and refractive index changes (RICs) between the ground and the excited states of the GaAs spherical quantum dot (QD) under the effect of Kratzer confining potential and laser field have been investigated theoretically. The electronic energy levels and their corresponding wave functions are obtained by solving Schrodinger equation using finite difference method within the effective mass approximation. The dependency of energies, probability densities, dipole matrix elements on the Kratzer potential parameters and on the size of QD are investigated. The use of density matrix formalism is made to study the variations in linear, nonlinear ACs and RICs with the energy and intensity of the laser field. Also the effect of variation of the QD size and Kratzer potential parameters on linear, nonlinear ACs and RICs are studied.

Intersubband optical absorption coefficients and refractive index changes in modulation-doped asymmetric double quantum well

The effect of terahertz laser field on the optical absorption coefficients and refractive index changes of hyperbolic confinement quantum wells

The linear and nonlinear optical properties in a wurtzite In x Ga 1-x N / Al y Ga 1-y N strained spherical quantum dot (QD) subjected to a uniform external electric field with a direction opposite to that of the built-in electric (BEF) within the framework of effective-mass approximation have been investigated. The results show that the BEF has great effects on the linear and nonlinear optical absorption coefficients (ACs) and refractive index (RI) changes. Moreover, the dependence of the linear and nonlinear optical properties on the In composition, on the Al composition and on the inner sphere radius has been studied in detail. It is indicated that the ACs and RI changes of the Wurtzite spherical QD have strongly affected by these factors. The results may make a significant contribution to designing some important photodetectors and photonic crystal devices.

Optical properties of an off-center hydrogenic impurity in a spherical quantum dot with Gaussian potential

Linear and nonlinear intersubband optical absorption and refractive index change in asymmetrical semi-exponential quantum wells

Within the quasi-one-dimensional effective potential model and effective mass approximation, we obtain the wavefunctions and energy eigenvalues of the ground (j = 1) and first 2 excited states (j = 2 and 3) of a donor impurity in a rectangular GaAs quantum dot in the presence of electric field. The donor impurity-related linear and nonlinear optical absorption as well as refractive index changes for the transitions j = 1−2 and j = 2−3 are investigated. The results show that the impurity position, incident optical intensity and electric field play important roles in the optical absorption coefficients and refractive index changes. We find that the impurity effect induces the blueshift for j = 1−2 and redshift for j = 3−2 in the absence of the electric field, but it leads to redshift for j = 1−2 and blueshift for j = 3−2 in the existence of the field. Also, the optical coefficient for the higher energy transitions j = 2−3 is insensitive to variation of impurity positions, while that for the low energy transition j = 1−2 depends significantly on the positions of impurity. In addition, the saturation and splitting phenomenon of the optical absorption are observed as the incident optical intensity increases.

Electric field-induced modulation of electronic and optical properties in doped CdTe/CdS core/shell quantum dots embedded in an oxide matrix

A study of nonlinear optical properties of a negative donor quantum dot

Confinement effects of Kratzer potential on a Wannier-Mott Exciton(W-M) are studied in a spherical quantum dot(QD) in the presence of a static magnetic field. Time independent Schr$\ddot{o}$dinger equation is solved numerically to obtain the energy states. The excitonic transitions so realized have been used to explore the non-linear optical properties that are important for optical characterization of materials such as the optical absorption coefficients (ACs) and refractive index changes (RICs). Impact of magnetic field, strength of the laser field and transition parameters using familiar compact density matrix approach are also analyzed. It has been observed that optical properties get radically modified under confinement effects. Also, the shift of degeneracy of different excitonic energy levels with the magnetic field in confinement potential has been reported for the first time for W-M exciton in the spherical quantum dot, the study that may have crucial input to the literature and myriad of practical implications.

Studies aimed at understanding the nonlinear optical (NLO) properties of GaAs/Ga0.7Al0.3As morse quantum well (QW) have focused on the intersubband optical absorption coefficients (OACs) and refractive index changes (RICs). These studies have taken two complimentary approaches: (1) The compact-density-matrix approach and iterative method have been used to obtain the expressions of OACs and RICs in morse QW. (2) Finite difference techniques have been used to obtain energy eigenvalues and their corresponding eigenfunctions of GaAs/Ga0.7Al0.3As morse QW under an applied magnetic field, hydrostatic pressure, and temperature. Our results show that the hydrostatic pressure and magnetic field have a significant influence on the position and the magnitude of the resonant peaks of the nonlinear OACs and RICs. Simultaneously, a saturation case is observed on the total absorption spectrum, which is modulated by the hydrostatic pressure and magnetic field. Physical reasons have been analyzed in depth.

The effect of metal nano particle on optical absorption coefficient of multi-layer spherical quantum dot

Consequences of dielectric mismatch on linear and third order nonlinear optical properties for CdS/ZnSe core/shell QD-matrix