Study of optical properties of a plasmonic nanoparticle on a dielectric substrate

Document Type : Research Paper

Authors

1 Department of physics, Faculty of Science, Razi university, Kermanshah,Iran

2 Department of physics, Razi university, Kermanshah,Iran

3 Department of physics, Faculty of Science, Razi University, Kermanshah,Iran

Abstract

By studying the polarizability of a spherical metallic nanoparticle on a dielectric substrate, the optical properties of the system is investigated. Since the size of nanoparticle is much smaller than the wavelength of the incident light, by solving the Laplace equation, the electric potential at different regions is expanded in terms of multipoles. By using the polarizability tensor, expressions for the parallel and normal polarizability are derived and then numerical results discussed. In addition to the impact of the size of plasmonic nanoparticle, by defining a geometrical parameter that called the truncation parameter, the impact of this parameter on the parallel and normal components of polarizability tensor is shown. It is demonstrated that the optical dispersion and absorption strongly depends on the particle size, the type of metal particle and the truncation parameter. The type of nanoparticle is gold and silver, because these noble metals have predominately been the materials of choice for plasmonic applications around the optical frequencies.

Keywords


[1] K. L. Kelly, E. Coronado, L. L. Zhao, and G. C. Schatz, “The Optical Properties of Metal Nanoparticles: The Influence of Size, Shape, and Dielectric Environment,” J. Phys. Chem. B, 107 (2003) 668-677.
[2] G. Doria , J. Conde, B. Veigas, L. Giestas, C. Almeida,M. Assuncao, J. Rosa and
P. V. Baptista, “Noble Metal Nanoparticles for Biosensing Applications”. Sensors,
12 (2012) 1657-1687.
[3] M. M. Wind, J. Vlieger and D. Bedeaux, “The polarizability of a truncated
sphere on a substrate I”, Physica, 141A (1987) 33-57.
[4] M. M. Wind, J. Vlieger and D. Bedeaux, “The polarizability of a truncated
sphere on a substrate II”, Physica, 143A (1987) 164-182.
[5] M. M. Wind, J. Vlieger and D. Bedeaux, “The polarizability of truncated spheres and oblate spheroids on a substrate: comparison with experimental results”, Thin Solid Films 164 (1988) 57-62.
[6] M. Haarmans and D. Bedeaux, The polarizability and the optical properties of lattices and random distributions of small metal spheres on a substrate, Thin Solid Films 224 (1993) 117-131.
[7] I. Simonsen, R. Lazzari, J. Jupille and S. Roux, ''Numerical modeling of the optical response of supported metallic particles'', Phys. Rev. B, 61 (2000) 7722.
[8] P. R. West, S. Ishii, G. V. Naik, N. K. Emani, V. M. Shalaev, and A. Boltasseva,"Searching for  better  plasmonic  materials",  Laser  Photonics  Rev,  4 (2010) 795-808.
[9]  Y.  Wanga, E.  W.  Plummerb and  K.  Kempa, "Foundations of  Plasmonics", Advances in Physics, 60 (2011) 799–898.
[10] K. S. Lee and M. A. El-Sayed, “Gold and Silver Nanoparticles in Sensing and Imaging: Sensitivity of Plasmon Response to Size, Shape, and Metal Composition”, J. Phys. Chem. B, 110 (2006) 19220-19225.
[11] S. Lal, S. Link and N. J. Halas , "Nano-optics from sensing to waveguiding", Nature photonics, 1 (2007) 641-648.