Light-assisted, templated self-assembly of gold nanoparticle chains

Nano Lett. 2014 Sep 10;14(9):5184-8. doi: 10.1021/nl502083m. Epub 2014 Aug 29.

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.

Keywords: Optical trapping; optical binding; optical manipulation; photonic crystal; plasmonics; self-assembly.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.