| 1. |
- Odebo Länk, Nils, 1988, et al.
(författare)
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Directional scattering and multipolar contributions to optical forces on silicon nanoparticles in focused laser beams
- 2018
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087 .- 1094-4087. ; 26:22, s. 29074-29085
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Tidskriftsartikel (refereegranskat)abstract
- Nanoparticles made of high index dielectric materials have seen a surge of interest and have been proposed for various applications, such as metalenses, light harvesting and directional scattering. With the advent of fabrication techniques enabling colloidal suspensions, the prospects of optical manipulation of such nanoparticles becomes paramount. High index nanoparticles support electric and magnetic multipolar responses in the visible regime and interference between such modes can give rise to highly directional scattering, in particular a cancellation of back-scattered radiation at the first Kerker condition. Here we present a study of the optical forces on silicon nanoparticles in the visible and near infrared calculated using the transfer matrix method. The zero-backscattering Kerker condition is investigated as an avenue to reduce radiation pressure in an optical trap. We find that while asymmetric scattering does reduce the radiation pressure, the main determining factor of trap stability is the increased particle response near the geometric resonances. The trap stability for non-spherical silicon nanoparticles is also investigated and we find that ellipsoidal deformation of spheres enables trapping of slightly larger particles.
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| 2. |
- Miljkovic, Vladimir, 1982, et al.
(författare)
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Simulating light scattering from supported plasmonic nanowires
- 2012
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087 .- 1094-4087. ; 20:10, s. 10816-10826
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Tidskriftsartikel (refereegranskat)abstract
- We present a method for calculating the differential scattering cross sections from nanostructures close to an interface separating two semi-infinitive dielectric media. The method combines a fast finite element software (Comsol multiphysics), used for calculations of the fields around and inside the structure, and the Green's functions method, which is used to find the far field distribution from the calculated total fields inside the nanostructure. We apply the method to calculations of scattering spectra from silver nanowires supported by an air-glass interface, a system that is of high current interest in relation to various nanophotonics applications. The results are analyzed in relation to analytical models and compared to experimentally measured spectra, to which we find a good agreement.
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| 3. |
- Miljkovic, Vladimir, 1982, et al.
(författare)
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Mode-specific directional emission from hybridized particle-on-a-film plasmons
- 2011
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Ingår i: Optics Express. - 1094-4087. ; 19:14, s. 12856-12864
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the electromagnetic interaction between a gold nanoparticle and a thin gold film on a glass substrate. The coupling between the particle plasmons and the surface plasmon polaritons of the film leads to the formation of two localized hybrid modes, one low-energy. film-like. plasmon and one high-energy plasmon dominated by the nanoparticle. We find that the two modes have completely different directional scattering patterns on the glass side of the film. The high-energy mode displays a characteristic dipole emission pattern while the low-energy mode sends out a substantial part of its radiation in directions parallel to the particle dipole moment. The relative strength of the two radiation patterns vary strongly with the distance between the particle and the film, as determined by the degree of particle-film hybridization. (C) 2011 Optical Society of America
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