scholarly journals Effects of Polaron and Quantum Confinement on the Nonlinear Optical Properties in a GaAs/Ga1-xAlxAs Quantum Well Wire

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
L. Caroline Sugirtham ◽  
A. John Peter ◽  
Chang Woo Lee
Keyword(s):  
Quantum Well ◽  
Quantum Confinement ◽  
Photoionization Cross Section ◽  
Third Order ◽  
Third Harmonic ◽  
Quantum Well Wire ◽  
Geometrical Effect ◽  
Theoretical Results ◽  
Order Susceptibility ◽  
Good Agreement

The binding energy of a polaron confined in a GaAs/Ga1-xAlxAs quantum well wire is calculated within the framework of the variational technique and Lee-Low Pines approach. The polaron-induced photoionization cross section as a function of normalized photon energy for a on-centre donor impurity in the quantum wire is investigated. The oscillator strength with the geometrical effect is studied taking into account the polaron effects in a GaAs/Ga0.8Al0.2As quantum well wire. The effect of polaron on the third-order susceptibility of third harmonic generation is studied. Our theoretical results are shown to be in good agreement with previous investigations.

Averaged third-order susceptibility of ZnO nanocrystals from Third Harmonic Generation and Third Harmonic Scattering

2018 ◽  
Vol 84 ◽  
pp. 579-585 ◽  
Author(s):  
V.V. Multian ◽  
J. Riporto ◽  
M. Urbain ◽  
Y. Mugnier ◽  
G. Djanta ◽  
...  
Keyword(s):  
Harmonic Generation ◽  
Third Harmonic Generation ◽  
Third Order ◽  
Third Harmonic ◽  
Zno Nanocrystals ◽  
Order Susceptibility

Polaron Effects on the Third-Order Susceptibility of a CdSe/ZnS Quantum Dot Quantum Well

2009 ◽  
Vol 64 (9-10) ◽  
pp. 625-631
Author(s):  
Xi Zhang ◽  
Guiguang Xiong ◽  
Xiaobo Feng
Keyword(s):  
Quantum Dot ◽  
Quantum Well ◽  
Photon Energy ◽  
Longitudinal Optical ◽  
Detailed Calculation ◽  
Phonon Modes ◽  
Third Order ◽  
The Third ◽  
Surface Optical ◽  
Order Susceptibility

Theoretical investigation of the polaron effects on the third-order susceptibility associated with the intersubband transition in the conduction band in a CdSe/ZnS quantum dot quantum well is presented. Contributions from the confined longitudinal optical (LO) and surface optical phonon modes are considered and the wave function is derived under the frame work of the perturbation theory. We carried a detailed calculation of third-harmonic generation (THG), Quadratic electro-optic effects (QEOE), and electro-absorption (EA) process on such a quantum dot as a function of pump photon energy with different incident photon energy and under different sizes. The results reveal that the polaron effects are quite important especially around the peak value of the third-order susceptibility. By increasing the size of the quantum dots, the peaks of χ(3)THG, χ(3)QEOE, and χ(3)EA will shift to the lower energy, and the intensities of the peaks will increase.

Diffused Quantum Well Structures: Advances in Materials and Device Realizations

1996 ◽  
Vol 450 ◽  
Author(s):  
E. Herbert Li
Keyword(s):  
Quantum Well ◽  
State Of The Art ◽  
Bulk Materials ◽  
Third Order ◽  
Quantum Well Structures ◽  
Future Developments ◽  
Multiple Phase ◽  
Reflectance Change ◽  
Multiple Species ◽  
Order Susceptibility

ABSTRACTThe Diffused Quantum Well (DFQW) structures created by both impurity induced and impurity free or vacancy promoted processes have recently been advanced to a higher level. The interdiffusion mechanism is no longer confined to two constituent atoms, but consists of two or multiple phase interdiffusion as well as multiple species, such as three cations interdiffusion and two pairs of cation-anion interdiffusion. Results show that the outcome of these interdiffusions is quite different. For instance, both compressive or tensile strain materials and both blue or red shifts in the bandgap can be achieved dependent on the type of interdiffusion. The advantage of being able to tune the material properties allows the realizations of higher performance lasers and modulators. Two lasing wavelengths (60 nm apart) are produced at λ ∼ 1.55μm, on the same substrate, with threshold currents of 290mA, and an extremely large relative reflectance change (over 10000) is predicted with power consumption reduced by 67%. A six fold enhancement of the third order susceptibility over that of the bulk materials can be achieved by using the inter-subband transitions in the DFQW at λ ∼ μm. Broadband (1000nm) detectors have also been realized due to the wide DFQW spectral bandwidth. Several state-of-the-art results of the DFQW will be summarized with an emphasis on the future developments and directions of the DFQW.

K-shell photoionization of Be-like nitrogen from the ground state: energies and Auger widths of the high-lying double-excited states for N IV

2018 ◽  
Vol 96 (11) ◽  
pp. 1183-1191
Author(s):  
Liang Liang ◽  
Chao Zhou
Keyword(s):  
Cross Sections ◽  
Ground State ◽  
Photoionization Cross Section ◽  
Coupling Scheme ◽  
Close Coupling ◽  
Resonance Energies ◽  
Auger Spectra ◽  
Distorted Wave Method ◽  
Theoretical Results ◽  
Good Agreement

The K-shell photoionization cross section of Be-like nitrogen (N IV) from the ground state is studied with the R-matrix and distorted-wave method for photon energies from 5.7 to 41.2 Ry. The close-coupling expansion includes 34 target states of N V with the 13 configurations in the LS-coupling scheme. The resonance energies, quantum defect and widths of 18 series of autoionization are determined from QB method and agree with these by cross sections. Our theoretical resonance energies and widths are compared with the existing experiments on the Auger spectra and other theoretical results. The results show that the calculated resonance energies are in rather good agreement with the experiment on the Auger spectra. For the autoionization width of some resonance states, good agreement is also found with recent theoretical results wherever available obtained using a saddle-point complex-rotation method.

scholarly journals Structural, optical, thermal and NLO behavior of zinc hydrogen maleate dihydrate single crystal

2018 ◽  
Vol 35 (4) ◽  
pp. 773-784
Author(s):  
S. Karuna ◽  
A.R. Balu ◽  
S. Muthu ◽  
D. Shyamala ◽  
Z. Delci ◽  
...  
Keyword(s):  
Single Crystal ◽  
Energy Gap ◽  
Basis Set ◽  
Potential Energy Distribution ◽  
Third Order ◽  
Tauc Plot ◽  
Ft Ir ◽  
Homo Lumo ◽  
Order Susceptibility ◽  
Good Agreement

Abstract Single crystal of zinc hydrogen maleate dihydrate (ZHMD) is grown by slow evaporation method at room temperature. The compound crystallizes in triclinic system with noncentrosymmetric space group P1. FT-IR and FT-Raman spectra of ZHMD are recorded. The versatile DFT is employed to understand the band structure of the crystal. Dipole moment of the molecule, ionization energy and electron affinity are established. The potential energy distribution PED of the vibrational modes is calculated using VEDA4. The results of the optimized molecular structure are compared with the single crystal XRD data. The Mulliken and NBO charges are calculated and interpreted. Optical properties of the grown crystal are analyzed using UV-Vis spectrum. Energy gap determined by Tauc plot is in a good agreement with the theoretical value calculated from HOMO-LUMO energies. Thermogravimetric analysis is done to assess the thermal behavior of the ZHMD crystal. Various thermodynamic parameters are calculated using the basis set B3LYP. The first order hyperpolarizability values of ZHMD establish its NLO nature. The molecular electrostatic potential MEP of the molecule is obtained. Third-order nonlinear response is studied using Z-scan technique and the corresponding parameters such as absorption coefficient, refractive index and third-order susceptibility are determined.

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