title: Dark-field microscopy studies of polarization-dependent plasmonic resonance of single gold nanorods: rainbow nanoparticles.
abstract: Orientation sensors require the monitoring of polarization-dependent surface plasmons of single nanoparticles. Herein, we present both the longitudinal and transverse surface plasmonic resonance from a single gold nanorod (AuNR) using conventional dark-field microscopy. The relative peak intensities of the transverse and longitudinal surface plasmons of a single AuNR can be successfully tuned by polarized excitation, which is an important step towards the use of transverse plasmon resonance of single AuNRs without photo-induced reshaping of nanoparticles. More interestingly, compared with AuNRs with small diameters, unique optical properties from AuNRs with diameters greater than 30 nm are revealed. As a result, optical images with different colors, rainbow nanoparticles (sea green, brown, red, yellow and green), depending on the polarization angle, can be revealed by a single AuNR. This result holds great promise for polarization-controlled colorimetric nanomaterials and single particle tracers in living cells and microfluidic flows.
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, 637457, Singapore.
authors.forename: Youju
authors.initials: Y
authors.lastname: Huang
authors.forename: Dong-Hwan
authors.initials: DH
authors.lastname: Kim
mesh_terms: D003116:Color; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008853:Microscopy; D036103:Nanotechnology; D043942:Nanotubes / Q000737:chemistry / Q000648:ultrastructure*; D010316:Particle Size; D020349:Surface Plasmon Resonance
chemical_list: D006046:Gold