title: Dark-field optical tweezers for nanometrology of metallic nanoparticles.
abstract: Applications of metallic nanoparticles are based on their strongly size-dependent optical properties. We present a method for combining optical tweezers with dark field microscopy that allows measurement of localised surface plasmon resonance (LSPR) spectra on single isolated nanoparticles without compromising the strength of the optical trap. Using this spectroscopic information in combination with measurements of trap stiffness and hydrodynamic drag, allows us to determine the dimensions of the trapped nanoparticles. A relationship is found between the measured diameters of the particles and the peak wavelengths of their spectra. Using this method we may also resolve complex spectra of particle aggregation and interactions within the tweezers.
authors.affiliation: School of Physics, The University of New South Wales,Sydney, NSW, Australia.
authors.forename: Kellie
authors.initials: K
authors.lastname: Pearce
authors.forename: Fan
authors.initials: F
authors.lastname: Wang
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Reece
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D053768:Metal Nanoparticles / Q000032:analysis* / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation*; D052898:Optical Tweezers; D013057:Spectrum Analysis / Q000295:instrumentation*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*