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Pal S.,Hetampur Raj High School | Sinha S.S.,Jackson State University | Ganguly J.,Brahmankhanda Basapara High School | Ghosh M.,Visva Bharati University
Chemical Physics | Year: 2013

We investigate the excitation kinetics of a repulsive impurity doped quantum dot initiated by simultaneous application of Gaussian white noise and external sinusoidal field. We have considered both additive and multiplicative noise (in Stratonovich sense). The combined influences of noise strength (ζ) and the field intensity (ε) have been capsuled by invoking their ratio (η). The said ratio and the dopant location have been found to fabricate the kinetics in a delicate way. Moreover, the influences of additive and multiplicative nature of the noise on the excitation kinetics have been observed to be widely different. The investigation reveals emergence of maximization/minimization and saturation in the excitation kinetics as a result of complex interplay between η and the dopant coordinate (r0). The present investigation is believed to provide some useful insights in the functioning of mesoscopic devices where noise plays some significant role. © 2013 Elsevier B.V. All rights reserved. Source


Ganguly J.,Brahmankhanda Basapara High School | Saha S.,Bishnupur Ramananda College | Pal S.,Hetampur Raj High School | Ghosh M.,Visva Bharati University
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2016

We make an extensive investigation of linear, third-order nonlinear, and total optical absorption coefficients (ACs) of impurity doped quantum dots (QDs) in presence and absence of noise. The noise invoked in the present study is a Gaussian white noise. The quantum dot is doped with repulsive Gaussian impurity. Noise has been introduced to the system additively and multiplicatively. A perpendicular magnetic field acts as a source of confinement and a static external electric field has been applied. The AC profiles have been studied as a function of incident photon energy when several important parameters such as optical intensity, electric field strength, magnetic field strength, confinement energy, dopant location, relaxation time, Al concentration, dopant potential, and noise strength take on different values. In addition, the role of mode of application of noise (additive/multiplicative) on the AC profiles has also been analyzed meticulously. The AC profiles often consist of a number of interesting observations such as one photon resonance enhancement, shift of AC peak position, variation of AC peak intensity, and bleaching of AC peak. However, presence of noise alters the features of AC profiles and leads to some interesting manifestations. Multiplicative noise brings about more complexity in the AC profiles than its additive counterpart. The observations indeed illuminate several useful aspects in the study of linear and nonlinear optical properties of doped QD systems, specially in presence of noise. The findings are expected to be quite relevant from a technological perspective. © 2015 Elsevier B.V. All rights reserved. Source


Ganguly J.,Brahmankhanda Basapara High School | Pal S.,Hetampur Raj High School | Ghosh M.,Visva Bharati University
Superlattices and Microstructures | Year: 2013

We investigate the excitation kinetics of a repulsive impurity doped quantum dot initiated by the application of additive Gaussian white noise. The noise and the dot confinement sources of electric and magnetic origin have been found to fabricate the said kinetics in a delicate way. In addition to this the dopant location also plays some prominent role. The present study sheds light on how the individual or combined variation of different confinement sources could design the excitation kinetics in presence of noise. The investigation reveals emergence of maximization and saturation in the excitation kinetics as a result of complex interplay between various parameters that affect the kinetics. The phase space plots are often invoked and they lend credence to the findings. The present investigation is believed to provide some useful perceptions of the functioning of mesoscopic systems where noise plays some profound role. © 2013 Elsevier Ltd. All rights reserved. Source


Ganguly J.,Brahmankhanda Basapara High School | Pal S.,Hetampur Raj High School | Ghosh M.,Visva Bharati University
Superlattices and Microstructures | Year: 2013

We investigate the excitation kinetics of a repulsive impurity doped quantum dot initiated by the application of multiplicative Gaussian white noise. The noise strength and the dot confinement sources of electric and magnetic origin have been found to produce the said kinetics in a subtle way. In addition to this the dopant location also plays some crucial role. The present study sheds light on how the individual or combined variation of different confinement sources could design the excitation kinetics in presence of noise. The investigation reveals maximization and saturation in the excitation kinetics as a result of complex interplay between the confinement potentials of the dot, the dopant location, and the noise strength. The present investigation is believed to provide some useful perceptions of the functioning of mesoscopic systems where noise plays some profound role.© 2013 Elsevier Ltd. All rights reserved. Source


Ganguly J.,Brahmankhanda Basapara High School | Ghosh M.,Visva Bharati University
Physica Status Solidi (B) Basic Research | Year: 2016

We perform an exhaustive exploration of profiles of second harmonic generation (SHG) coefficient of impurity-doped quantum dots (QDs) in presence and absence of noise. The quantum dot is doped with Gaussian impurity. Noise has been applied to the system additively and multiplicatively. A perpendicular magnetic field emerges out as a confinement source and a static external electric field has been applied. The SHG profiles have been pursued as a function of incident photon energy when several important parameters such as electric field strength, magnetic field strength, confinement energy, dopant location, Al concentration, dopant potential, and noise strength assume different values. Moreover, the role of mode of application of noise (additive/multiplicative) on the SHG profiles has also been critically analyzed. The SHG profiles are found to be enriched with interesting observations such as shift of SHG peak position and maximization/minimization of SHG peak intensity. Presence of noise alters the features of SHG profiles through some interesting outcomes. Furthermore, the mode of application of noise (additive/multiplicative) also regulates the SHG profiles in diverse as well as often contrasting manners. The observations highlight the possibilities of tuning the SHG coefficient of doped QD systems in presence of noise. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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