title: Plasmofluidic single-molecule surface-enhanced Raman scattering from dynamic assembly of plasmonic nanoparticles.
abstract: Single-molecule surface-enhanced Raman scattering (SM-SERS) is one of the vital applications of plasmonic nanoparticles. The SM-SERS sensitivity critically depends on plasmonic hot-spots created at the vicinity of such nanoparticles. In conventional fluid-phase SM-SERS experiments, plasmonic hot-spots are facilitated by chemical aggregation of nanoparticles. Such aggregation is usually irreversible, and hence, nanoparticles cannot be re-dispersed in the fluid for further use. Here, we show how to combine SM-SERS with plasmon polariton-assisted, reversible assembly of plasmonic nanoparticles at an unstructured metal-fluid interface. One of the unique features of our method is that we use a single evanescent-wave optical excitation for nanoparticle assembly, manipulation and SM-SERS measurements. Furthermore, by utilizing dual excitation of plasmons at metal-fluid interface, we create interacting assemblies of metal nanoparticles, which may be further harnessed in dynamic lithography of dispersed nanostructures. Our work will have implications in realizing optically addressable, plasmofluidic, single-molecule detection platforms.
authors.affiliation: Photonics and Optical Nanoscopy Laboratory, h-cross, Indian Institute of Science Education and Research, Pune 411008, India.
authors.forename: Partha Pratim
authors.initials: PP
authors.lastname: Patra
authors.affiliation: Photonics and Optical Nanoscopy Laboratory, h-cross, Indian Institute of Science Education and Research, Pune 411008, India.
authors.forename: Rohit
authors.initials: R
authors.lastname: Chikkaraddy
authors.affiliation: Photonics and Optical Nanoscopy Laboratory, h-cross, Indian Institute of Science Education and Research, Pune 411008, India.
authors.forename: Ravi P N
authors.initials: RP
authors.lastname: Tripathi
authors.affiliation: Photonics and Optical Nanoscopy Laboratory, h-cross, Indian Institute of Science Education and Research, Pune 411008, India.
authors.forename: Arindam
authors.initials: A
authors.lastname: Dasgupta
authors.affiliation: Photonics and Optical Nanoscopy Laboratory, h-cross, Indian Institute of Science Education and Research, Pune 411008, India.
authors.forename: G V Pavan
authors.initials: GV
authors.lastname: Kumar