Tuning of nonlinear optical characteristics of a cylindrical quantum dot by external fields and structure parameters
Abstract
In this present study, we have theoretically investigated the
effect of applied external electric field and non-resonant
intense laser field, as well as the adjustable physical
parameters (A, M, and η) of the system, on the linear and
nonlinear of GaAs/GaAlAs cylindrical quantum dot. The
confinement potential of the quantum dot is composed of
the axial potential with a Razavy-type quantum well in the
z-direction, and the cylindrical-type potential in the radial
direction. To achieve this goal, the wave functions, and the
corresponding eigenvalues of the electron are investigated
by resolving the time-independent Schrödinger equation
using the diagonalisation technique in terms of the
effective mass approximation. The linear and nonlinear
optical properties’ expressions have been calculated with
the help of the compact density matrix method. Our
numerical results show that by changing the A, M, and η
parameters, we can see a blueshift or redshift in the total
optical absorption coefficients (TOACs) and relative
refractive index changes (RRICs). Additionally, they are
redshifted, and their extrema increase as the radius
increases. The increase in electric field or laser field
intensities generates a strong displacement of the resonant
peak position towards the higher energies, diminishes the
TOACs magnitude, and shrinks RRICs extrema. The model
potential used in the computation is important, and the
study of it will be practical in the development and
research of nanostructures systems.