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.

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 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.

Nonlinear Intersubband Optical Absorption Coefficient and Refractive Index Changes in Asymmetric Parabolic Double Quantum Wells

2017 ◽  
Vol 6 (1) ◽  
pp. 121-125 ◽  
Author(s):  
Menberu Mengesha Woldemariam
Keyword(s):  
Refractive Index ◽  
Optical Absorption ◽  
Absorption Coefficient ◽  
Quantum Wells ◽  
Optical Absorption Coefficient ◽  
Double Quantum ◽  
Absorption Coefficients ◽  
Total Change ◽  
Left Handed ◽  
Index Changes

The change in optical absorption coefficients and refractive index in GaAs-AlGaAs asymmetric parabolic double quantum wells (DQWs) with applied electric field are studied in detail. Analytical expressions for the linear, nonlinear and total intersubband absorption coefficient and refractive index changes are obtained by using compact density matrix approach. It is found that the magnitude of the nonlinear part of the change in refractive index and absorption coefficients are larger than the linear part in the given frequency region. The value of the total change in refractive index is negative and the asymmetric DQWs becomes left handed media. This property is of great importance for metamaterials science and can contribute substantially to the present search for simple and inexpensive left handed media. Moreover the negative value of the total change in absorption coefficient may be used for developing optical device such as maser at different frequency regime.

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