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Ganguly J.,Brahmankhanda Basapara High School | Saha S.,Bishnupur Ramananda College | Pal S.,Hetampur Raj High School | Ghosh M.,Visva Bharati University
Optics Communications | Year: 2016

We perform a meticulous analysis of profiles of third-order nonlinear optical susceptibility (TONOS) of impurity doped quantum dots (QDs) in the presence and absence of noise. We have invoked Gaussian white noise in the present study and noise has been introduced to the system additively and multiplicatively. The QD is doped with a Gaussian impurity. A magnetic field applied perpendicularly serves as a confinement source and the doped system has been exposed to a static external electric field. The TONOS profiles have been monitored against a continuous variation of incident photon energy when several important parameters such as electric field strength, magnetic field strength, confinement energy, dopant location, Al concentration, dopant potential, relaxation time, anisotropy, and noise strength assume different values. Moreover, the influence of mode of introduction of noise (additive/multiplicative) on the TONOS profiles has also been addressed. The said profiles are found to be consisting of interesting observations such as shift of TONOS peak position and maximization/minimization of TONOS peak intensity. The presence of noise alters the features of TONOS profiles and sometimes enhances the TONOS peak intensity from that of noise-free state. Furthermore, the mode of application of noise also often tailors the TONOS profiles in diverse fashions. The observations accentuate the possibility of tuning the TONOS of doped QD systems in the presence of noise. © 2015 Elsevier B.V. All rights reserved.


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.


Ganguly J.,Brahmankhanda Basapara High School | Saha S.,Bishnupur Ramananda College | Ghosh M.,Visva Bharati University
Chemical Physics Letters | Year: 2015

We explore the profiles of off-diagonal components of frequency-dependent linear, first, and second nonlinear polarizabilities of impurity doped quantum dot. The dopant propagates in an environment that damps the motion. Simultaneous presence of noise inherent to the system has also been considered. The dopant has a Gaussian potential and noise considered is a Gaussian white noise. Noise-damping coupling strength appears to be the key parameter that designs the profiles of polarizability components. The frequency of external field also affects the profiles of Polarizability components. The present investigation highlights some interesting features in the optical properties of doped quantum dots. © 2014 Elsevier B.V. All rights reserved.


Ganguly J.,Brahmankhanda Basapara High School | Ghosh M.,Visva Bharati University
Journal of Applied Physics | Year: 2014

We investigate the profiles of diagonal components of frequency-dependent first nonlinear (βxxx and βyyy) optical response of repulsive impurity doped quantum dots. We have assumed a Gaussian function to represent the dopant impurity potential. This study primarily addresses the role of noise on the polarizability components. We have invoked Gaussian white noise consisting of additive and multiplicative characteristics (in Stratonovich sense). The doped system has been subjected to an oscillating electric field of given intensity, and the frequency-dependent first nonlinear polarizabilities are computed. The noise characteristics are manifested in an interesting way in the nonlinear polarizability components. In case of additive noise, the noise strength remains practically ineffective in influencing the optical responses. The situation completely changes with the replacement of additive noise by its multiplicative analog. The replacement enhances the nonlinear optical response dramatically and also causes their maximization at some typical value of noise strength that depends on oscillation frequency. © 2014 AIP Publishing LLC.


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.


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.


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.


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.


Ganguly J.,Brahmankhanda Basapara High School | Ghosh M.,Visva Bharati University
Chemical Physics | Year: 2014

We investigate the profiles of diagonal components of frequency-dependent linear (αxx and αyy) optical response of repulsive impurity doped quantum dots. The dopant impurity potential chosen assumes Gaussian form. The study principally puts emphasis on investigating the role of noise on the polarizability components. In view of this we have exploited Gaussian white noise containing additive and multiplicative characteristics (in Stratonovich sense). The frequency-dependent polarizabilities are studied by exposing the doped dot to a periodically oscillating external electric field of given intensity. The oscillation frequency, confinement potentials, dopant location, and above all, the noise characteristics tune the linear polarizability components in a subtle manner. Whereas the additive noise fails to have any impact on the polarizabilities, the multiplicative noise influences them delicately and gives rise to additional interesting features. © 2014 Elsevier B.V. All rights reserved.


Ganguly J.,Brahmankhanda Basapara High School | Ghosh M.,Visva Bharati University
Physica Status Solidi (B) Basic Research | Year: 2015

We investigate the profiles of diagonal components of static and frequency-dependent third nonlinear (γxxxx, γyyyy) polarizability of repulsive impurity doped quantum dots driven by noise. The dopant impurity potential is represented by a Gaussian function. We have invoked Gaussian white noise applied additively and multiplicatively (in Stratonovich sense). In order to determine the polarizability components, the doped system is subject to an external electric field of given intensity, which may be static or time-dependent. The dopant location and the noise characteristics delicately tailor the polarizability components and produce good number of interesting outcomes. Quiet significantly, we have found ineffectiveness of the noise strength in influencing the polarizability components when the noise is applied additively. However, the multiplicative noise behaves otherwise and gives rise to additional interesting features in the polarizability profiles. The multiplicative noise even causes noticeable enhancement in the magnitude of the polarizability components. The present enquiry gains importance in view of the fact that noise seriously affects the optical properties of doped quantum dot devices. The findings could be relevant within the purview of noise driven optical properties of doped quantum dot systems. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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