Controlling surface plasmon excitation of pair arrays of metallic nanocylinders
ABSTRACT Surface plasmon excitation of pair arrays of silver nanocylinders is studied using finite-difference time-domain simulations.
Strong local fields are generated around the nanocylinders due to excitation of localized surface plasmon and electromagnetic
fields are confined effectively in the gaps between the nanocylinders. Surface plasmon resonance and local-field enhancement
of two-pair arrays can be controlled by changing the illumination direction of the incident light due to induced asymmetric
polarization charges. Complex resonant modes could be excited with increasing number of silver nanocylinder pairs. Selective
local-field enhancement is observed in the gaps of the pairs by changing the interpair distance of four-pair arrays.
SourceAvailable from: P. Arun Palakkandy[Show abstract] [Hide abstract]
ABSTRACT: We study numerically the near field surface plasmon characteristics of a triangular system of silver nano cylinders that interact with incident plane wave using finite element method as well as 2-D finite difference time domain method. The influence of the dielectric environment, radius, inter particle distance, and orientation of the source plane on the optical resonances of the nano cylinders was investigated. The strength of the near field intensity is found to be strongly dependent on the orientation of the incident field. The number and magnitude of the near field resonances depends on the cylinder dimension as well as the cylinder separation. The plasmon coupling between nanocylinders increases with increase in dielectric constant of the environment and this sensitivity can form the basis for novel plasmonics based chemo- and bio-sensing applications.Journal of Computational and Theoretical Nanoscience 06/2013; 10(6):1418-1424. DOI:10.1166/jctn.2013.2863 · 1.03 Impact Factor
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ABSTRACT: In this report we have studied the near field and the far field plasmonic prop-erties of gold nanocylinders arranged linearly in a Fibonacci number chain and compared the results with those arranged in a conventional geometry. Assigning the radius of first two nanocylinders as 10nm, we have arranged five gold nanocylinders linearly with radii varying according to Fibonacci numbers and compared the optical properties with conventional geometry. Using FEM simulation we explored the near field distribution and the far field radiation pattern of the two geometries for various excitation angles. Our study reveals significant backscattered intensity in the far field radia-tion pattern for excitation angles along the chain for Fibonacci geometry, which was otherwise absent in conventional geometry. A systematic variation in near field enhancement is observed as a function of excitation angles which could guide us to tune Raman enhancement by changing the angle of excitation. We have obtained the maximum near field enhancement in the gap of two largest nanocylinders which is in contrast to the results obtained in the self similar chain of nanostructures. In addition we have explored the polarization dependent plasmonic properties of 1D silver nanowires and observed the strong dependence of incident polarization on propagation of surface plasmon polaritons.05/2012, Degree: M.S., Supervisor: Dr. G.V. Pavan Kumar
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ABSTRACT: Plasmonic wave propagation in a chain waveguide created by a triangular array of silver nanoshell cylinder was investigated using finite element method and Finite Difference Time Domain Method. It is observed that the trimer nanoshell cylinder array provides better field propagation compared to single-chain and pair-chain nanoshell cylinder arrays. Results show that the resonant wavelength of the structure is highly sensitive to the permittivity of either the core or the surrounding medium. It is also observed that as the core thickness of the waveguide is increased surface plasmon resonance shows a red shift.Waves in Random and Complex Media 08/2013; 23(3). DOI:10.1080/17455030.2013.803171 · 1.11 Impact Factor