Abstracts - Dipartimento di Elettronica Applicata

Meta 2010 & FEM 2010 – Rome, 13-15 December 2010
Controlling Optical Forces on Nanoparticles
through Metamaterials
Simone Tricarico, Filiberto Bilotti and Lucio Vegni
University “Roma Tre”, Department of Applied Electronics
Rome, Italy – E-mail: stricarico@uniroma3.it
In this contribution, we propose a theoretical analysis showing how
metamaterials conformal covers surrounding a given nanoscatterer may be
effectively used not only to design cloaking devices [1,2], but also to
synthesize shells able to control acting optical forces [3]. Here, we extend the
scattering cancellation approach in order to derive the proper conditions under
which plasmonic media or metamaterials can be used to manipulate optical
forces exerted by the illuminating radiation on a Rayleigh particle. In the long
wavelength limit, in fact, such kind of forces are directly related to the
amplitude of the object electric polarizability. Since scattering cancellation
technique relies in suppressing the scattered field by nullifying the
polarizability of the overall object, we may exploit the inherently dispersive
behavior metamaterials to design a suitable cover able to govern optical forces
(see Figure 1).
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f) b)
Figure 1 – a) Gradient force field distribution for a bare dielectric spherical particle placed in
the interference region of two orthogonal standing waves with zero phase shift. b) Gradient
force field distribution in the same configuration for a dielectric spherical covered by a
metamaterial shell. At the working frequency (zero crossing of the electric polarizability) the
gradient force is minimized.
References
[1] A. Alù and N. Engheta, “Achieving transparency with plasmonic and metamaterial
coatings,” Phys. Rev. E, 72, 016623, 2005
[2] S. Tricarico, F. Bilotti, and L. Vegni, “Reduction of optical forces exerted on nanoparticles
covered by scattering cancellation based plasmonic cloaks,” Phys. Rev. B, 82,
045109, 2010
[2] S. Tricarico, F. Bilotti, A. Alù, and L. Vegni, “Plasmonic Cloaking for Irregular Objects
with Anisotropic Scattering Properties,” Phys. Rev. E, 81, 026602, 2010
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