title: Light-assisted, templated self-assembly of gold nanoparticle chains.
abstract: We experimentally demonstrate the technique of light-assisted, templated self-assembly (LATS) to trap and assemble 200 nm diameter gold nanoparticles. We excite a guided-resonance mode of a photonic-crystal slab with 1.55 μm laser light to create an array of optical traps. Unlike our previous demonstration of LATS with polystyrene particles, we find that the interparticle interactions play a significant role in the resulting particle patterns. Despite a two-dimensionally periodic intensity profile in the slab, the particles form one-dimensional chains whose orientations can be controlled by the incident polarization of the light. The formation of chains can be understood in terms of a competition between the gradient force due to the excitation of the mode in the slab and optical binding between particles.
authors.affiliation: Ming Hsieh Department of Electrical Engineering and §Department of Physics and Astronomy, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Eric
authors.initials: E
authors.lastname: Jaquay
authors.forename: Luis Javier
authors.initials: LJ
authors.lastname: Martínez
authors.forename: Ningfeng
authors.initials: N
authors.lastname: Huang
authors.forename: Camilo A
authors.initials: CA
authors.lastname: Mejia
authors.forename: Debarghya
authors.initials: D
authors.lastname: Sarkar
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Povinelli
keywords: Optical trapping; optical binding; optical manipulation; photonic crystal; plasmonics; self-assembly