title: Direct visualization of near-fields in nanoplasmonics and nanophotonics.
abstract: Electric fields of nanoscale particles are fundamental to our understanding of nanoplasmonics and nanophotonics. Success has been made in developing methods to probe the effect of their presence, but it remains difficult to directly image optically induced electric fields at the nanoscale and especially when ensembles of particles are involved. Here, using ultrafast electron microscopy, we report the space-time visualization of photon-induced electric fields for ensembles of silver nanoparticles having different sizes, shapes, and separations. The high-field-of-view measurements enable parallel processing of many particles in the ensemble with high throughput of information. Directly in the image, the evanescent fields are observed and visualized when the particles are polarized with the optical excitation. Because the particle size is smaller than the wavelength of light, the near-fields are those of nanoplasmonics and are precursors of far-field nanophotonics. The reported results pave the way for quantitative studies of fields in ensembles of complex morphologies with the nanoparticles being embedded or interfacial.
authors.affiliation: Physical Biology Center for Ultrafast Science and Technology Arthur Amos Noyes Laboratory of Chemical Physics California Institute of Technology, Pasadena, California 91125, United States.
authors.forename: Aycan
authors.initials: A
authors.lastname: Yurtsever
authors.forename: Ahmed H
authors.initials: AH
authors.lastname: Zewail
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D008422:Materials Testing / Q000295:instrumentation*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D010783:Photometry / Q000295:instrumentation* / Q000379:methods*; D012834:Silver / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000295:instrumentation* / Q000379:methods*
chemical_list: D012834:Silver