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Published June 2012 | public
Journal Article

Direct Visualization of Near-Fields in Nanoplasmonics and Nanophotonics


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.

Additional Information

© 2012 American Chemical Society. Received: May 1, 2012. Publication Date (Web): May 17, 2012. This work was supported by the National Science Foundation (DMR-0964886) and the Air Force Office of Scientific Research (FA9550-11-1-0055) in the Gordon and Betty Moore Center for Physical Biology at the California Institute of Technology. We wish to thank Dr. Sang Tae Park for the helpful discussion on the theory of PINEM and for the calculation provided in Figure 4 (bottom panel).We are especially grateful to Dr. Spencer Baskin who contributed to the excellent performance of the laser system and optical arrangement inside the microscope. The authors declare no competing financial interest.

Additional details

August 19, 2023
October 17, 2023