Exciton-related nonlinear optical properties in cylindrical quantum dots with asymmetric axial potential: combined effects of hydrostatic pressure, intense laser field, and applied electric field
Abstract:The exciton binding energy of an asymmetrical GaAs-Ga1−xAlxAs cylindrical quantum dot is studied with the use of the effective mass approximation and a variational calculation procedure. The influence on this quantity of the application of a direct-current electric field along the growth direction of the cylinder, together with that of an intense laser field, is particularly considered. The resulting states are used to calculate the exciton-related nonlinear optical absorption and optical rectification, whose … Show more
“…On the other hand, the nonlinear optical properties of QD structures have also been considered quite extensively in the literature (see, for instance, , and references therein). Actually, it is not possible to underrate the importance of the study of the optical responses in these quantum nanosystems.…”
Section: Introductionmentioning
confidence: 99%
“…In particular, the finite element method (FEM) allows for solving the quantum mechanical problem of finding the allowed carrier states in all spatial dimensions and in the cases where the geometry of the system shows irregularities or symmetries that cannot be treated analytically [20]. On the other hand, the nonlinear optical properties of QD structures have also been considered quite extensively in the literature (see, for instance, [21][22][23][24][25][26][27][28], and references therein). Actually, it is not possible to underrate the importance of the study of the optical responses in these quantum nanosystems.…”
The optical absorption response of an elliptical quantum‐dot‐type nanostructure is investigated by numerically determining the electron states within the effective mass and parabolic approximations via the finite element method, taking into account the effect of an externally applied electric field. Validation of the numerical procedure is discussed through the comparison with analytical results of previous works for zero external field conditions. For finite field, the comparison is made with the outcome of degenerate perturbation theory. The calculated electron energies and wavefunctions are used to evaluate the linear and nonlinear light absorption and refractive index change coefficients in the system. Their corresponding expressions are those typically derived within a perturbative approach for solving the density matrix equation of motion. It is shown how the electric field and the change in the elliptical geometry affect the optical response of the considered structures. The extension of the treatment to consider the properties of elliptic nanoparticles under external field influences is briefly discussed.
“…On the other hand, the nonlinear optical properties of QD structures have also been considered quite extensively in the literature (see, for instance, , and references therein). Actually, it is not possible to underrate the importance of the study of the optical responses in these quantum nanosystems.…”
Section: Introductionmentioning
confidence: 99%
“…In particular, the finite element method (FEM) allows for solving the quantum mechanical problem of finding the allowed carrier states in all spatial dimensions and in the cases where the geometry of the system shows irregularities or symmetries that cannot be treated analytically [20]. On the other hand, the nonlinear optical properties of QD structures have also been considered quite extensively in the literature (see, for instance, [21][22][23][24][25][26][27][28], and references therein). Actually, it is not possible to underrate the importance of the study of the optical responses in these quantum nanosystems.…”
The optical absorption response of an elliptical quantum‐dot‐type nanostructure is investigated by numerically determining the electron states within the effective mass and parabolic approximations via the finite element method, taking into account the effect of an externally applied electric field. Validation of the numerical procedure is discussed through the comparison with analytical results of previous works for zero external field conditions. For finite field, the comparison is made with the outcome of degenerate perturbation theory. The calculated electron energies and wavefunctions are used to evaluate the linear and nonlinear light absorption and refractive index change coefficients in the system. Their corresponding expressions are those typically derived within a perturbative approach for solving the density matrix equation of motion. It is shown how the electric field and the change in the elliptical geometry affect the optical response of the considered structures. The extension of the treatment to consider the properties of elliptic nanoparticles under external field influences is briefly discussed.
“…There has been extensive work devoted to investigate the influence of these aspects on the electronic structure and optical properties of semiconductor QDs [30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55].…”
“…In the researches above, changing the shapes and sizes of quantum systems is often used to do researches on nonlinear optical effects. For example, cubic [3,4], spherical [5][6][7][8], diskshaped [9][10][11][12], cylindrical [13][14][15], ring [16] quantum dots are studied by some researchers. Besides, there are many physical factors that have great influences on nonlinear optical effects.…”
Section: Introductionmentioning
confidence: 99%
“…Therefore, some authors do some researches by adding the number of electrons such as two electrons [9,17,18] and consider polaron [13,[19][20][21] and excitonic [22][23][24] effects. Moreover, the application of an electric field [14,16,18,25], a magnetic field [12,13,26], impurity [10,16,25], spin-orbit interaction [4,27] and external perturbation like hydrostatic pressure [14,16], temperature [14,16] and intense laser field [14,28,29], exhibits novel nonlinear optical phenomena. Besides, changing the confinement potential in quantum structures is a very useful method.…”
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