Spatial confinement of electromagnetic hot and cold spots in gold nanocubes.

Haggui, Mohamed; Dridi, Montacer; Plain, Jérôme; Marguet, Sylvie; Perez, Henri; Schatz, George C; Wiederrecht, Gary P; Gray, Stephen K et al. · ACS Nano · 2012

basic_science · Level V

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Abstract

We report a near-field imaging study of colloidal gold nanocubes. This is accomplished through a photochemical imaging method in which molecular displacements are vectorial in nature, enabling sensitivity to the polarization of the optical near-field of the nanocubes. We analyze the confinement of both electromagnetic hot and "cold" spots with a resolution of λ/35 and emphasize the particularly high spatial confinement of cold spots. The concept of a cold spot complements the well-known electromagnetic hot spot but can have significant advantages. The application of the ultraconfined cold spots to high resolution imaging and spectroscopy is discussed.

Medical subject headings