| 1. |
- Miljkovic, Vladimir, 1982, et al.
(författare)
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Optical Forces in Plasmonic Nanoparticle Dimers
- 2010
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 114:16, s. 7472-7479
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Tidskriftsartikel (refereegranskat)abstract
- We present calculations of the optical forces between two metal nanospheres forming a hybridized plasmonic chiller. We consider homo- and heterodimers and investigate different plane wave illumination configurations. The forces between the particles are calculated using kill Mie theory combined with the Maxwell stress tensor (MST) formalism, as well as by approximate methods, such as the Lorentz force (LF) approach taken in the dipole limit and calculations based on an optical potential. We show that the simplified calculation schemes can lead to serious errors in the case of strongly interacting particles and low damping. In particular, we find that equilibrium configurations, corresponding to vanishing optical forces, only are possible for homodimers illuminated in the end-fire configuration and for heterodimers, although multipolar effects and clamping radically reduce the repulsive interactions in the latter case.
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| 2. |
- Tong, Lianming, 1981, et al.
(författare)
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Alignment, Rotation, and Spinning of Single Plasmonic Nanoparticles and Nanowires Using Polarization Dependent Optical Forces
- 2010
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 10:1, s. 268-273
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate optical alignment and rotation of individual plasmonic nanostructures with lengths from Lens of nanometers to several micrometers using a single beam of linearly polarized near-infrared laser light. Silver nanorods and dimers of gold nanoparticles align parallel to the laser polarization because of the high long-axis dipole polarizability. Silver nanowires, in contrast, spontaneously turn perpendicular to the incident polarization and predominantly attach at the wire ends, in agreement with electrodynamics simulations. Wires, rods, and dimers all rotate if the incident polarization is turned. In the case of nanowires, we demonstrate spinning at an angular frequency of similar to 1 Hz due to transfer of spin angular momentum from circularly polarized light.
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| 3. |
- Tong, Lianming, 1981, et al.
(författare)
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Optical manipulation of plasmonic nanoparticles using laser tweezers
- 2010
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9780819482587 ; 7762
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Plasmonic nanoparticles, typically gold and silver colloids, can be trapped by a highly focused Gaussian beam. The behavior of the particles in an optical trap, such as the alignment, stability and interaction between particles, depends on their plasmonic nature, determined by the correlation between the size, shape and material of the particles, and the wavelength and polarization of the trapping laser. For instance, an elongated nanoparticle aligns parallel to the polarization of a NIR trapping laser to minimize the optical potential energy. However, nanowires tend to align perpendicular to the polarization. A dimer of two isotropic nanoparticles in principle acts similar to a nanorod with its "long axis" (dimer axis) parallel to the laser polarization. These results are evidenced by dark-field scattering imaging and spectra, and agree well with discrete dipole approximation simulations of the near-fields around different nanostructures. Elongated nanoparticles, dimers and nanowires all rotate when the laser polarization is rotated. Irradiated under a circularly polarized laser, trapped objects spin spontaneously due to the transfer of angular momentum from the incident photons. The interaction between two gold nanoparticles in a dimer is complex because it involves the optical potential and the DLVO potential. The latter can be probed to some extent using dark-field scattering spectroscopy. © 2010 SPIE.
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