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Optical forces on interacting plasmonic nanoparticles in a focused Gaussian beam

Z. P. Li ; Mikael Käll (Institutionen för teknisk fysik, Bionanofotonik) ; H. Xu
Physical Review B (1098-0121). Vol. 77 (2008), 8, p. 6.
[Artikel, refereegranskad vetenskaplig]

We theoretically analyze optical forces on aggregates of metal nanoparticles in a focused Gaussian beam by extending the generalized Mie theory, which includes higher order multipoles and retardation effects. For two interacting metallic particles, an attractive gradient force, mainly caused by multipole plasmon excitation, exists at short interparticle distances, while induced dipolar fields dominate for separations of the order of the particle radius R or larger. The long-range force component can be either attractive or repulsive depending on the phase of the induced dipoles, as determined by the illumination wavelength and the collective dipolar plasmon resonance. In particular, the repulsive force that occurs for illumination near the plasmon resonance wavelength can be so large that it overcomes the optical trapping effect of the Gaussian beam.

Nyckelord: ENHANCED RAMAN-SCATTERING, LORENZ-MIE THEORY, LOCALIZED APPROXIMATION, RIGOROUS JUSTIFICATION, ELECTROMAGNETIC-FIELD, METAL NANOPARTICLES, SHAPE COEFFICIENTS, DIELECTRIC SPHERE, LIGHT-SCATTERING, AXIS BEAMS



Denna post skapades 2009-10-27. Senast ändrad 2016-08-19.
CPL Pubid: 100855

 

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Institutioner (Chalmers)

Institutionen för teknisk fysik, Bionanofotonik (2007-2015)

Ämnesområden

Teknisk fysik

Chalmers infrastruktur