K. Porsezian

Pondicherry University, Pondichéry, Pondicherry, India

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Publications (256)331.25 Total impact

  • R. Radha · P.S. Vinayagam · K. Porsezian
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    ABSTRACT: We investigate a generalized coupled nonlinear Schrodinger (GCNLS) equation containing Self-Phase Modulation (SPM), Cross-Phase Modulation (XPM) and Four Wave Mixing (FWM) describing the propagation of electromagnetic radiation through an optical fibre and generate the associated Lax-pair. We then construct bright solitons employing gauge transformation approach. The collisional dynamics of bright solitons indicates that it is not only possible to manipulate intensity (energy) between the two modes (optical beams), but also within a given mode unlike the Manakov model which does not have the same freedom. The freedom to manipulate intensity (energy) in a given mode or between two modes arises due to a suitable combination of SPM, XPM and FWM. While SPM and XPM are controlled by an arbitrary real parameter each, FWM is governed by two arbitrary complex parameters. The above model may have wider ramifications in nonlinear optics and Bose-Einstein Condensates (BECs).
    No preview · Article · Feb 2016 · Communications in Nonlinear Science and Numerical Simulation
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    T. Mithun · K. Porsezian · Bishwajyoti Dey
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    ABSTRACT: We study the vortex lattice dynamics in presence of single impurity as well as random impurities or disorder. We show that in presence of a single impurity the vortex lattice gets distorted and the distortion depends on the position of the single impurity with respect to the positions of the vortices in the impurity free Abrikosov vortex lattice and also the strength of the impurity potential. We then show that a new type of giant hole with hidden vortices inside it can be created in the vortex lattice by a cluster of impurities. In presence of random impurity potential or disorder the vortex lattice melts. We show that the vortex lattice also melts in presence of pseudorandom potential generated by the superposition of two optical lattices. The absence of long-range order in the melted vortex lattice is demonstrated from the structure factor profile and the histogram of the distances between each pair of the vortices.
    Full-text · Article · Jan 2016
  • K Nithyanandan · K Porsezian
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    ABSTRACT: A theoretical study of cross phase modulation (XPM) induced modulational instability (MI) in a semiconductor doped dispersion decreasing fiber (SD-DDF) is presented. The equation is suitably modeled to account for the saturable nonlinearity and dispersion decreasing nature of the fiber. Using linear stability analysis, the exact dispersion relation is obtained and MI analysis is performed. We exclusively analyze the influence of the walk-off effect in the instability spectra of an SD-DDF and an optimum walk-off parameter is identified. The contrasting nature of action of decreasing dispersion and saturating nonlinearity is emphasized, such that the former enhances and the latter suppresses bandwidth. Thus, a suitable combination of the two physical effects can enable one to realize the desired bandwidth profile. MI analysis in the normal dispersion regime is compared with the anomalous counterpart as well as the conventional single pump case and the results are tabulated. Also, our analytical results are compared through direct numerical simulation and the results are documented. Thus, we present a comprehensive study of XPM-MI in an SD-DDF and the influence of various physical effects on the MI dynamics.
    No preview · Article · Jan 2016 · Laser Physics
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    Ishfaq Ahmad Bhat · T. Mithun · B. A. Malomed · K. Porsezian
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    ABSTRACT: We study modulation instability (MI) of flat states in two-component spin-orbit-coupled (SOC) Bose-Einstein condensates (BECs) in the framework of coupled Gross-Pitaevskii equations for two components of the pseudospinor wave function. The analysis is performed for equal densities of the components. Effects of the interaction parameters, Rabi coupling, and SOC on the MI are investigated. In particular, the results demonstrate that the SOC strongly alters the commonly known MI (immiscibility) condition, g122>g1g2, for the binary superfluid with coefficients g1,2 and g12 of the intra- and interspecies repulsive interactions. In fact, the binary BEC is always subject to the MI under the action of the SOC, which implies that the ground state of the system is plausibly represented by a striped phase.
    Full-text · Article · Dec 2015 · Physical Review A
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    Feng Yuan · Deqin Qiu · Wei Liu · K. Porsezian · Jingsong He
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    ABSTRACT: The localization characters of the first-order rogue wave (RW) solution $u$ of the Kundu-Eckhaus equation is studied in this paper. We discover a full process of the evolution for the contour line with height $c^2+d$ for the first-order RW $|u|^2$: A point at height $9c^2$ generates a convex curve for $3c^2\leq d<8c^2$, whereas it becomes a concave curve for $0<d<3c^2$, next it reduces to a hyperbola on asymptotic plane (i.e. equivalently $d=0$), and the two branches of the hyperbola become two separate convex curves when $-c^2<d<0$, and finally they reduce to two separate points at $d=-c^2$. Using the contour line method, the length, width, and area of the RW at height $c^2+d (0<d<8c^2)$ , i.e. above the asymptotic plane, are defined. We study the evolutions of three above-mentioned localization characters on $d$ through analytical and visual methods.
    Full-text · Article · Oct 2015
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    ABSTRACT: We present a practical design of novel photonic crystal fibre (PCF) to investigate the nonlinear propagation of femtosecond pulses for the application of optical coherence tomography (OCT) based on supercontinuum generation (SCG) process. In addition, this paper contains a brief introduction of the physical phenomena of soliton and SCG. Typically, here we discuss how the ultrabroadband radiation in PCF can be generated by SCG through various nonlinear effects of the fibre. To accomplish the proposed aim, we put forth liquid core PCF (LCPCF) structure filled with chloroform for OCT measurements of the eye. From the proposed design, we observe that proposed LCPCFs with liquid material exhibit significant broadened wavelength spectrum with low input pulse energy over small propagation distances for the OCT application.
    Full-text · Article · Oct 2015 · Pramana
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    ABSTRACT: We study the stabilization properties of dipolar Bose-Einstein condensate by temporal modulation of short-range two-body interaction. Through both analytical and numerical methods, we analyze the mean-field Gross-Pitaevskii equation with short-range two-body and long-range, nonlocal, dipolar interaction terms. We derive the equation of motion and effective potential of the dipolar condensate by variational method. We show that there is an enhancement of the condensate stability due to the inclusion of dipolar interaction in addition to the two-body contact interaction. We also show that the stability of the dipolar condensate increases in the presence of time varying two-body contact interaction; the temporal modification of the contact interaction prevents the collapse of dipolar Bose-Einstein condensate. Finally we confirm the semi-analytical prediction through the direct numerical simulations of the governing equation.
    No preview · Article · Oct 2015 · Physical Review E
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    ABSTRACT: We investigate the nonlinear dynamics and steering performance of structurally asymmetric triple-core photonic crystal fiber (ATPCF) for the accomplishment of efficient all-optical logic gates. We study two kinds of ATPCF, one with planar and the other with triangular core setting. The effective mode indices are obtained through the finite element method. The dynamics and steering characteristics of ATPCF are numerically explored via coupled nonlinear Schrödinger equations. The extinction ratios for the various logic gate operations are determined in the presence of suitable control signal. ATPCFs are found to demonstrate efficient logic gate operation; in addition, they highlight the practical issue of geometrical tolerance in PCF design.
    Full-text · Article · Aug 2015 · Journal of the Optical Society of America B
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    ABSTRACT: We study the amplitude perturbations of the cubic–quintic Gross–Piteavskii equation for weakly trapped Bose–Einstein condensates through a semiquantum procedure. After a quantization of the original problem, with the introduction of quantum degrees of freedom as the fluctuations around classical parameters, a new dynamical modulational instability condition is derived. Corrective terms bear quantum effects that play a crucial role over the reshape of instability domain and sometimes train all unstable modes into full stability. By making use of several indicators through direct numerical simulations of the subsequent set of equations of motion, we found that there are rooms of regular trajectories and those of totally chaotic ones that are strictly related to instability. These numerical results are in agreement with the analytical predictions regarding the stabilization of Bose–Einstein condensates.
    Full-text · Article · Jul 2015 · Chaos Solitons & Fractals
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    Deqin Qiu · Jingsong He · Yongshuai Zhang · K Porsezian
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    ABSTRACT: We construct an analytical and explicit representation of the Darboux transformation (DT) for the Kundu– Eckhaus (KE) equation. Such solution and n-fold DT T n are given in terms of determinants whose entries are expressed by the initial eigenfunctions and 'seed' solutions. Furthermore, the formulae for the higher order rogue wave (RW) solutions of the KE equation are also obtained by using the Taylor expansion with the use of degenerate eigenvalues λ 2k−1 → λ 1 = − 1 2 a + βc 2 + ic, k = 1, 2, 3,. . ., all these parameters will be defined latter. These solutions have a parameter β, which denotes the strength of the non-Kerr (quintic) nonlinear and the self-frequency shift effects. We apply the contour line method to obtain analytical formulae of the length and width for the first-order RW solution of the KE equation, and then use it to study the impact of the β on the RW solution. We observe two interesting results on localization characters of β, such that if β is increasing from a/2: (i) the length of the RW solution is increasing as well, but the width is decreasing; (ii) there exist a significant rotation of the RW along the clockwise direction. We also observe the oppositely varying trend if β is increasing to a/2. We define an area of the RW solution and find that this area associated with c = 1 is invariant when a and β are changing.
    Full-text · Article · Jul 2015 · Proceedings of The Royal Society A Mathematical Physical and Engineering Sciences
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    ABSTRACT: We study the transverse instability associated with higher-dimensional nonlinear systems. For this, a cubic-quintic-nonlinear system is considered wherein the coefficients of cubic and quintic terms are allowed to be of either focusing or defocusing nature. It is found that focusing-cubic and defocusing-quintic nonlinearity can suppress the transverse instability growth rate. The addition of guiding potentials can also suppress the instability growth rate for all kinds of solitons with the same propagation constant.
    Full-text · Article · Jun 2015 · Journal of the Optical Society of America B
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    ABSTRACT: We consider a next-higher-order extension of the Chen–Lee–Liu equation, i.e., a higher-order Chen–Lee–Liu (HOCLL) equation with third-order dispersion and quintic nonlinearity terms. We construct the n-fold Darboux transformation (DT) of the HOCLL equation in terms of the n × n determinants. Comparing this with the nonlinear Schrödinger equation, the determinant representation T n of this equation is involved with the complicated integrals, although we eliminate these integrals in the final form of the DT, so that the DT of the HOCLL equation is unusual. We provide explicit expressions of multi-rogue wave (RW) solutions for the HOCLL equation. It is concluded that the rogue wave solutions are likely to be crucial when considering higher-order nonlinear effects.
    Full-text · Article · May 2015 · Physica Scripta
  • K Nithyanandan · K Porsezian
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    ABSTRACT: We investigate the modulational instability (MI) induced Supercontinuum generation (SCG) in exponential saturable nonlinearity. The pump power (P) is observed to behave in a unique way such that unlike the conventional Kerr case, the effective nonlinearity of saturable nonlinear system does not monotonously increases with an increase in power. The supercontinuum is observed at the shortest distance of propagation at power equal to the saturation power (Ps), whereas for all combinations of powers (P Ps or P > Ps) spectral broadening occurs at longer distance.
    No preview · Article · Apr 2015 · Journal of Physics Conference Series
  • K Nithyanandan · K Porsezian
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    ABSTRACT: We investigate the modulational instability (MI) of the optical beam propagating in the relaxing saturable nonlinear system. We identify and discuss the salient features of various functional forms of saturable nonlinear responses such as exponential, conventional and coupled type on the MI spectrum. Using Debye relaxation model, the relaxation of nonlinear response is effectively included along with the saturable nonlinear response (SNL). Using linear stability analysis, an explicit dispersion relation is determined for considering different functional forms of SNL. Firstly, we analyze the impact of SNL on the MI spectrum and found that the MI gain and bandwidth is maximum for exponential nonlinearity in comparison to other types of SNL's. Latter the relaxation of the nonlinearity is included, the inclusion of the finite value of the response time extends the range of the unstable frequencies literally down to infinite frequencies. In the regime of slow response, the MI inevitably suppressed regardless of the sign of the dispersion coefficient. To give insight into the MI phenomena, the maximum MI gain and the optimum modulation frequency is drawn as a function of the delay. Thus the MI dynamics in the system of relaxing saturable nonlinear media is emphasized and the significance of various functional forms of SNL are highlighted.
    No preview · Article · Apr 2015 · Journal of Physics Conference Series
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    P. S. Vinayagam · R. Radha · Vivek M. Vyas · K. Porsezian
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    ABSTRACT: We harness the freedom in the celebrated gauge transformation approach to generate dark solitons of coupled nonlinear Schr\"odinger (NLS) type equations. The new approach which is purely algebraic could prove to be very useful, particularly in the construction of vector dark solitons in the fields of nonlinear optics, plasma physics and Bose-Einstein condensates. We have employed this algebraic method to coupled Gross- Pitaevskii (GP) and NLS equations and obtained dark solitons.
    Full-text · Article · Mar 2015 · Romanian Reports in Physics
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    S. Sabari · K. Porsezian · R. Murali
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    ABSTRACT: We explain how the modulational and oscillatory instabilities can be generated in Bose–Einstein condensates (BECs) with two- and three-body interactions trapped in a periodic optical lattice with driving harmonic potential. We solve a cubic–quintic Gross–Pitaevskii (GP) equation with external trapping potentials by using both analytical and numerical methods. Using the time-dependent variational approach, we derive and analyze the variational equations for the time evolution of the amplitude and phase of modulational perturbation, and effective potential of the system. Through the effective potential, we obtain the modulational instability condition of the BECs with two- and three-body interactions and shown the effects of the optical potential on the dynamics of the system. We perform direct numerical simulations to support our analytical results, and good agreement is observed.
    Full-text · Article · Feb 2015 · Physics Letters A
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    ABSTRACT: A variety of AS2S3 chalcogenide photonic crystal fiber coupler of special properties are proposed to study the role of birefringence in all optical coupling characteristics based on the projection operator method (POM). The equations of motion describing the dynamics of the individual pulse parameters through x- and y-polarized modes are arrived at by employing POM from the coupled nonlinear Schrödinger equations. From the pulse parameter dynamics, it is observed that the amplitudes of the polarization components are significantly influenced by the pulse being introduced with different polarizing angle even at low input power level. Such a selective polarizing angles of the input pulse will provide efficient control over the desired splitting ratio as well as the ability to decide the desired polarization component.
    Full-text · Article · Jan 2015 · Journal of optics
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    Shafeeque Ali · K. Nithyanandan · K. Porsezian
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    ABSTRACT: We investigate the modulation instability (MI) in a three-core oppositely-directed coupler with a particular emphasis on a negative index material (NIM) channel. In order to give a comprehensive picture, we consider the normal and the anomalous dispersion regimes. Special attention is paid to investigation of the influence of system parameters such as the power and the coupling coefficient on the MI. We also analyze the impact of different nonlinear configurations of coupler channels on MI
    Full-text · Article · Jan 2015 · Physics Letters A
  • K. Nithyanandan · A.K. Shafeeque Ali · K. Porsezian
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    ABSTRACT: We proposed a novel semiconductor doped dispersion decreasing fiber (SD-DDF) for the ultrashort pulse generation using modulational instability. The two physical effects satruable nonlinearity and decreasing dispersion is found to behave in a unique way, such that the former suppress the MI bandwidth and the later enhances the bandwidth. This unique feature enable one to tailor and design a fiber for desired bandwidth profile by merely choosing the operating power, instead of choosing different fibers. Thus we emphasize that the proposed SD-DDF will be useful in wide range of applications, especially in the context of ultra-short pulse generation using MI.
    No preview · Article · Dec 2014
  • Uthayakumar Thangaraj · RVJ Raja · K. Porsezian
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    ABSTRACT: We present a novel asymmetric triple core photonic crystal fiber for the construction of NOR and OR logic gates by employing all optical control. Through extinction ratio calculated at apt control signal phase, the Boolean algebra for NOR and OR logic gates are demonstrated numerically.
    No preview · Conference Paper · Dec 2014

Publication Stats

2k Citations
331.25 Total Impact Points

Institutions

  • 2003-2016
    • Pondicherry University
      • Department of Physics
      Pondichéry, Pondicherry, India
  • 1993-2002
    • Anna University, Chennai
      • Department of Physics
      Chennai, Tamil Nadu, India
  • 1987-1998
    • Bharathidasan University
      • • Department of Physics
      • • Centre for Non-Linear Dynamics
      Tiruchchirāppalli, State of Tamil Nadu, India