Papers by amin h. al-khursan
Chinese Journal of Physics, Apr 1, 2021
Electromagnetically induced grating (EIG) in the ladder-plus-Y double quantum dot system is model... more Electromagnetically induced grating (EIG) in the ladder-plus-Y double quantum dot system is modeled and the diffraction grating properties are explored in this structure. A high transmission function is obtained under the high pump field. This function is reduced under increasing the probe field due to the Kerr effect. The phase of this function depends on pumping. It is shown that the application of another two fields from the wetting layer (WL)-quantum dot (QD) type is more efficient in obtaining very high diffraction intensity. So, EIG with high diffraction intensity is obtained under a four-field application. Note that, WL-QD field effect is not studied earlier. Neglecting the WL effect reduces the transmission by five times. The diffraction intensity of this system is six times higher than that obtained from a single QD structure.
Applied optics, Sep 7, 2016
The ladder-plus-Y double quantum dot structure was modeled for all-optical processing by combinin... more The ladder-plus-Y double quantum dot structure was modeled for all-optical processing by combining the density matrix theory with the pulse width description of the applied pulse. The momentum matrix elements are calculated including the wetting layer. The ladder-plus-Y structure exhibits pattern-free output with high bit rate (50 Tbps), which is critical in optical communication applications. It is shown that very high ground-state occupation with periodic shape for state occupations is critical in obtaining a pattern-free eye diagram.
Superlattices and Microstructures, Sep 1, 2017
Optical stability behavior in a unidirectional ring cavity containing a ladder-plus-Y double QD (... more Optical stability behavior in a unidirectional ring cavity containing a ladder-plus-Y double QD (DQD) structure was modeled in this work using the density matrix theory in parallel with Momentum matrix elements including interdot QD-QD transitions. QD-WL transitions, which were not included in any other bistability work in QD structures, are also modeled here. Pumping optical field reduces the threshold of optical bistability (OB). The coupling field, which dressing DQD states and strengthens Kerr nonlinearity are increased. It is shown that optical multistability (OM) was the figure of merit for the stability behavior in DQD system, in the contrary with other researches, as a result from considering the calculation of all transition
Optical and Quantum Electronics, 2020
Electromagnetically induced grating (EIG) in the ladder-plus-Y double quantum dot system is model... more Electromagnetically induced grating (EIG) in the ladder-plus-Y double quantum dot system is modeled and the diffraction grating properties are explored in this structure. A high transmission function is obtained under the high pump field. This function is reduced under increasing the probe field due to the Kerr effect. The phase of this function depends on pumping. It is shown that the application of another two fields from the wetting layer (WL)-quantum dot (QD) type is more efficient in obtaining very high diffraction intensity. So, EIG with high diffraction intensity is obtained under a four-field application. Note that, WL-QD field effect is not studied earlier. Neglecting the WL effect reduces the transmission by five times. The diffraction intensity of this system is six times higher than that obtained from a single QD structure.
Results in Physics, 2018
Extending optoelectronics into the nano-regime seems problematic due to the relatively long wavel... more Extending optoelectronics into the nano-regime seems problematic due to the relatively long wavelengths of light. The conversion of light into plasmons is a possible way to overcome this problem. Plasmon's wavelengths are much shorter than that of light which enables the propagation of signals in small size components. In this paper, a 3D simulation of surface plasmon polariton (SPP) excitation is performed. The Finite integration technique was used to solve Maxwell's equations in the dielectric-metal interface. The results show how the surface plasmon polariton was generated at the grating assisted dielectric-metal interface. SPP is a good candidate for signal confinement in small size optoelectronics which allow high density optical integrated circuits in all optical networks.
Recent Patents on Electrical Engineeringe, 2008
A theory of gain, refractive index, and linewidth enhancement factor in the quantum dots (QDs) in... more A theory of gain, refractive index, and linewidth enhancement factor in the quantum dots (QDs) in the nonthermal coupling (NTC) case is discussed. The ground and excited state transitions are included. Effect of parameters, like recombination time and radiative transition time, is studied. The study shows that the QDs can have zero linewidth enhancement factor. The present review covers important patents useful in this field.
Solid State Laser, 2012
It can be seen in the asymptotic, values are independent of the active medium length.
Physica E: Low-dimensional Systems and Nanostructures, 2006
... a Physics Department, Science College, Thi-Qar University, Nasiriya, Iraq. Received 29 August... more ... a Physics Department, Science College, Thi-Qar University, Nasiriya, Iraq. Received 29 August 2005; revised 27 February 2006; accepted 27 February 2006. Available online 26 July 2006. Abstract. In this work, we simulate the ...
Photonics and Nanostructures - Fundamentals and Applications, 2009
... a Physics Department, Science College, Thi-Qar University, Nassiriya, Iraq. b Physics Departm... more ... a Physics Department, Science College, Thi-Qar University, Nassiriya, Iraq. b Physics Department, Science College, Babylon University, Hillah, Iraq. c Physics Department, Science College, Al-Mustansiriyah University, Baghdad, Iraq. ...
Optik, 2013
Four wave mixing analysis is stated for quantum dot semiconductor optical amplifiers (QD SOAs) us... more Four wave mixing analysis is stated for quantum dot semiconductor optical amplifiers (QD SOAs) using the propagation equations (including nonlinear propagation contribution) coupled with the QD rate equations under the saturation assumption. Long wavelength III-nitride InN and AlInN QD SOAs are simulated. Asymmetric behavior due to linewidth enhancement factor is assigned. P-doping increases efficiency. Lossless efficiency for InAlN QDs for longer radii is obtained. Carrier heating is shown to have a considerable effect and a detuning dependence is expected at most cases. InN QD SOAs shown to have higher efficiency.
Physica Scripta, Sep 21, 2021
This work proposes a double quantum dot structure as an intermediate-band layer to developing sol... more This work proposes a double quantum dot structure as an intermediate-band layer to developing solar cell performance for the first time. The continuity-current equation is coupling with the density matrix equations, which are solved numerically to obtain the quantum efficiency. This modeling will calculate the momentum matrix elements of transitions, consider the orthogonalized plane wave for wetting layer- quantum dot transitions, and covers more characteristics than the rate equations by considering all the possible interactions between the states. The results simulate both the excitonic and nonexcitonic (electron-hole) cases. The work emphasizes adding the double quantum dot layer, which gives flexibility in choosing the energy difference between states controlling the recombination rates. The work refers to the importance of orthogonalized plane-wave in solar cell work. In both models, the band-band recombination is high for slight energy differences between the states, confirms the importance of the double quantum dot system to manipulate transitions between states and obtain higher rates. For the electron-hole model, the leakage is high due to the fast recombination of holes. The discrimination between occupations of states is increasing under the excitonic model due to growing hole occupation. In both models, reducing the quantum dot - quantum dot recombinations and increasing all other recombinations will increase the quantum efficiency. The high quantum dot band-to-band rate increases the quantum efficiency. In the excitonic model, lower rates than in the electron-hole model are enough for high quantum efficiency.
Micro and nanostructures, Jul 1, 2022
In this work, a double quantum dot (QD) structure is introduced as an intermediate band for highp... more In this work, a double quantum dot (QD) structure is introduced as an intermediate band for highperformance solar cells (SCs). Coupling the dynamical (density matrix) equations with the continuitycurrent equation and solving them numerically to obtain the quantum efficiency (QE). which allowed to address the interaction between all the states and band of SC which is not possible elsewhere and better than the rate equation modeling. Throughout this modeling, the momentum matrix elements of QD-QD, QD-wetting layer (WL), and WL-barrier transitions are calculated and the orthogonalized plane wave is assumed for WL-QD transitions. Results are simulated both the excitonic and non-excitonic (electronhole eh) cases and exhibit the importance of adding the QD layer. The valence band (VB) DQD states have similar occupations while the conduction band (CB) is not. The WL occupations are the smallest in both CB and VB as it works like a reservoir. These results confirm both the importance of adding the intermediate band (QD layer) and the carrier scenarios. The band-to-band recombination rates in the DQD structure are modulated with the energy difference. The VB relaxation rates between states are of the same order and lower than the corresponding CB rates related to their occupation. The occupations in the excitonic model do not much differ from the eh model. A few increments in the excitonic model in the CB and VB barrier-WL relaxation while a reduction in the VB WL-QD and QD-QD relaxation appears. The band-to-band recombination rates in the excitonic model are reduced compared to the eh model. The photo-generation rates have the highest rate at QDs. The quantum efficiency (QE) in the eh model is increased at semi-linear relation with VB relaxation rates while it is increased exponentially with CB rates. Longer relaxation times for WL-QD check it pleas transitions are attained with a wider energy difference. For the DQD structure, the longer relaxations and band-to-band recombinations are accessed depending on the wider energy difference.
In this work, a double quantum dot (QD) structure is introduced as an intermediate band for highp... more In this work, a double quantum dot (QD) structure is introduced as an intermediate band for highperformancesolar cells (SCs). Coupling the dynamical (density matrix) equations with the continuitycurrentequation and solving them numerically to obtain the quantum efficiency (QE). which allowed toaddress the interaction between all the states and band of SC which is not possible elsewhere and betterthan the rate equation modeling. Throughout this modeling, the momentum matrix elements of QD-QD,QD-wetting layer (WL), and WL-barrier transitions are calculated and the orthogonalized plane wave isassumed for WL-QD transitions. Results are simulated both the excitonic and non-excitonic (electronholeeh) cases and exhibit the importance of adding the QD layer.The valence band (VB) DQD states have similar occupations while the conduction band (CB) isnot. The WL occupations are the smallest in both CB and VB as it works like a reservoir. These resultsconfirm both the importance of adding the in...
Physica Scripta, 2021
This work proposes a double quantum dot structure as an intermediate-band layer to developing sol... more This work proposes a double quantum dot structure as an intermediate-band layer to developing solar cell performance for the first time. The continuity-current equation is coupling with the density matrix equations, which are solved numerically to obtain the quantum efficiency. This modeling will calculate the momentum matrix elements of transitions, consider the orthogonalized plane wave for wetting layer- quantum dot transitions, and covers more characteristics than the rate equations by considering all the possible interactions between the states. The results simulate both the excitonic and nonexcitonic (electron-hole) cases. The work emphasizes adding the double quantum dot layer, which gives flexibility in choosing the energy difference between states controlling the recombination rates. The work refers to the importance of orthogonalized plane-wave in solar cell work. In both models, the band-band recombination is high for slight energy differences between the states, confirms the importance of the double quantum dot system to manipulate transitions between states and obtain higher rates. For the electron-hole model, the leakage is high due to the fast recombination of holes. The discrimination between occupations of states is increasing under the excitonic model due to growing hole occupation. In both models, reducing the quantum dot - quantum dot recombinations and increasing all other recombinations will increase the quantum efficiency. The high quantum dot band-to-band rate increases the quantum efficiency. In the excitonic model, lower rates than in the electron-hole model are enough for high quantum efficiency.
Journal of optics/Journal of optics (New Delhi. Print), Feb 28, 2024
Optical and Quantum Electronics, Dec 1, 2009
The nonlinear (third-order) optical gain for quantum-dot structures is derived where the density ... more The nonlinear (third-order) optical gain for quantum-dot structures is derived where the density matrix theory is defined by the inhomogeneous density matrix elements. Thus, the nonlinear gain becomes completely inhomogeneous. The total gain obtained under complete inhomogeneous density matrix is shown to be asymmetric. This is not included earlier.
Optical and Quantum Electronics, Nov 19, 2019
In this work we present a model of the dielectric function in plasmonic quantum dot (QD) nanolase... more In this work we present a model of the dielectric function in plasmonic quantum dot (QD) nanolaser. A metal/semiconductor/metal structure was considered to attain plasmonic nanocavity with active region containing: QD, wetting layer and barrier. The dielectric function was calculated for both metal (Ag) and QD structure. The propagation constant of surface plasmon polariton (SPP) at the interface of Ag/InAs-QD structure was calculated and the dispersion relation of the plasmonic QD structure was evaluated. For frequencies far from plasma one, the gap between real and imaginary parts was large and a deviation from linear relation was obvious. The SPP field was strongly localized at the interface due to the effect of zero-dimensional QD structure which has application in the super-resolution and best sensitivity in optical imaging. Results of propagation length of SPP (L spp) also support this. According to the L spp results, the damping in the SPP energy was low in the Ag/InAs-QD compared to that in the Ag/air interface. The obtained results are in the range of experimental ones.
Optical and Quantum Electronics, 2021
This work studies quantum holography in a ladder-plus-Y double quantum dot system. The density ma... more This work studies quantum holography in a ladder-plus-Y double quantum dot system. The density matrix theory is used to model the system and an analytical solution of the susceptibility is done. Different parameters and situations are examined in this study. A comparison with the classical holograph is examined. A coincidence with the transmission amplitude is shown means that good holography of the object is performed.
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Papers by amin h. al-khursan