Optical properties of an exciton trapped by an ionized donor in ellipsoidal quantum dots under electric field and hydrostatic pressure

2019 ◽  
Vol 33 (12) ◽  
pp. 1950108 ◽  
Author(s):  
Lei Shi ◽  
Zu-Wei Yan
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Perturbation Theory ◽  
Hydrostatic Pressure ◽  
Electric Field ◽  
Absorption Coefficients ◽  
Third Order ◽  
Ellipsoidal Quantum Dot ◽  
Index Changes ◽  
Shape And Size

The optical properties of an exciton trapped by an ionized donor in an ellipsoidal quantum dot (QD) with both oblate and prolate shapes under applied electric field and hydrostatic pressure have been studied. We have calculated the linear and third-order nonlinear absorption coefficients (ACs) and refractive index changes (RICs) by using a variational method within the perturbation theory. The results show that the QD shape and size have a significant influence on the positions and magnitudes of the peaks of the (ACs) and RICs, moreover, the influence of hydrostatic pressure and electric field under different QD shape is also different.

Linear and nonlinear optical absorption coefficients and refractive index changes in Morse quantum wells under electric field

2016 ◽  
Vol 30 (30) ◽  
pp. 1650209 ◽  
Author(s):  
S. Sakiroglu
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Optical Absorption ◽  
Electric Field ◽  
Quantum Wells ◽  
Nonlinear Optical ◽  
Absorption Coefficients ◽  
Nonlinear Optical Absorption ◽  
Index Changes ◽  
Linear And Nonlinear

In this paper, we investigate theoretically the effects of electric field on the linear and nonlinear optical properties of Morse quantum wells considering a two-level system. The effective mass approximation and the envelope function approach are used to calculate the energy levels and wave functions. The analytical expressions of the optical properties are obtained by using the compact density-matrix approach. The linear and third-order nonlinear optical absorption coefficients and the refractive index changes are investigated as a function of the incident photon energy for several configurations of the structural parameter and the applied electric field. Numerical results, presented for a typical GaAs/AlGaAs quantum well, reveal that the electric field has a significant effect on the optical characteristics of these structures and intersubband transitions can be modified by tuning the structural range parameter of the potential.

scholarly journals Linear and Nonlinear Intersubband Optical Properties of Direct Band Gap GeSn Quantum Dots

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 124 ◽  
Author(s):  
Mourad Baira ◽  
Bassem Salem ◽  
Niyaz Madhar ◽  
Bouraoui Ilahi
Keyword(s):  
Quantum Dots ◽  
Refractive Index ◽  
Absorption Coefficient ◽  
Electron Energy ◽  
Energy State ◽  
Total Absorption ◽  
Absorption Coefficients ◽  
Third Order ◽  
Index Changes ◽  
Total Absorption Coefficient

Intersubband optical transitions, refractive index changes, and absorption coefficients are numerically driven for direct bandgap strained GeSn/Ge quantum dots. The linear, third-order nonlinear and total, absorption coefficients and refractive index changes are evaluated over useful dot sizes’ range ensuring p-like Γ-electron energy state to be lower than s-like L-electron energy state. The results show strong dependence of the total absorption coefficient and refractive index changes on the quantum dot sizes. The third order nonlinear contribution is found to be sensitive to the incident light intensity affecting both total absorption coefficient and refractive index changes, especially for larger dot sizes.

Electron–phonon interaction influence on optical properties of parallelogram quantum wires

2014 ◽  
Vol 28 (22) ◽  
pp. 1450142 ◽  
Author(s):  
H. Bahramiyan ◽  
R. Khordad ◽  
H. Azari
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Quantum Wire ◽  
Quantum Wires ◽  
Energy Levels ◽  
Moment Matrix ◽  
Absorption Coefficients ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Index Changes

In the present work, we have studied the effect of electron–phonon (e–p) interaction on optical properties of a GaAs quantum wire with parallelogram cross-section. For this goal, we have calculated refractive index changes and absorption coefficients by using compact-density-matrix approach and iterative method. The results show that the refractive index changes and absorption coefficients are obviously increased and the peak positions shift toward higher energies after considering the e–p interaction. We have also studied polaronic effect on electric dipole moment matrix elements and the energy levels for different quantum wire sizes. We have found that the line-width of absorption coefficients and refractive index changes is approximately constant after considering e–p interaction.

scholarly journals Study of non-linear optical properties of center and edge delta-doped multiple quantum wells

2018 ◽  
Vol 64 (5) ◽  
pp. 439 ◽  
Author(s):  
Monica Gambhir ◽  
Vinod Prasad
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Optical Absorption ◽  
Quantum Wells ◽  
Multiple Quantum ◽  
Absorption Coefficients ◽  
Non Linear ◽  
Linear Optical Properties ◽  
Index Changes ◽  
Linear Optical

In the present paper, the linear and non-linear optical properties of GaAs/AlGaAs multiple quantum well with on-center and on-edge delta doping are studied within the effective mass approximation. The delta potential is analytically modeled within each quantum well potential to obtain the energy levels and the corresponding wave functions using the robust finite difference method. The linear and non-linear optical absorption coefficients and changes in the refractive index are studied in the presence of a static magnetic and a periodic laser field using the density matrix approach. The obtained results show that the position of resonances and the amplitude of the optical absorption coefficients and the refractive index changes can be modified by varying the magnetic field and strength and position of doping potential. Lastly, an increase of the optical intensity appreciably changes the total absorption coefficient, as well as the total refractive index changes. Obtained results are important for the design of various electronic components such as high-power FETs and infrared photonic devices based on the intersubband transition of electrons in δ-doped multiple quantum wells.

LINEAR AND NONLINEAR INTERSUBBAND OPTICAL ABSORPTION OF FINITE AND INFINITE SEMI-PARABOLIC QUANTUM WELLS

2011 ◽  
Vol 25 (07) ◽  
pp. 497-507 ◽  
Author(s):  
M. J. KARIMI ◽  
A. KESHAVARZ ◽  
A. POOSTFORUSH
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Optical Absorption ◽  
Quantum Well ◽  
Quantum Wells ◽  
Resonant Peak ◽  
Energy Eigenvalues ◽  
Finite Case ◽  
Infinite Case ◽  
Index Changes

In this work, the optical absorption coefficients and the refractive index changes for the infinite and finite semi-parabolic quantum well are calculated. Numerical calculations are performed for typical GaAs / Al x Ga 1-x As semi-parabolic quantum well. The energy eigenvalues and eigenfunctions of these systems are calculated numerically. Optical properties are obtained using the compact density matrix approach. Results show that the energy eigenvalues and the matrix elements of the infinite and finite cases are different. The calculations reveal that the resonant peaks of the optical properties of the finite case occur at lower values of the incident photon energy with respect to the infinite case. Results indicate that the maximum value of the refractive index changes for the finite case are greater than that of the infinite case. Our calculations also show that in contrast to the infinite case, the resonant peak value of the total absorption coefficient in the case of the finite well is a non-monotonic function of the semi-parabolic confinement frequency.

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