Gap-Plasmon-Enhanced Nanofocusing Near-Field Microscopy

• DOI: 10.1021/acsphotonics.5b00438
• Publication Date: 2016-01-07T15:41:48Z
• Authors: Simon F. Becker; Martin Esmann; KyungWan Yoo; Petra Gross; Ralf Vogelgesang; NamKyoo Park; Christoph Lienau
• Keywords: Scanning Probe Microscopy

We report the observation of coherent light scattering from nanometer-sized gap regions in a nanofocusing scanning near-field optical microscope. When approaching gold taper to surface thin semitransparent film and detecting transmission, we find steep increase intensity over last 5 nm signal selected k-space. This is confirmed as signature highly confined plasmons by detailed comparisons finite element method simulations. The simulations reveal that confinement adjustable via underlying probe–sample distance control scheme even levels well below apex radius. controlled experimental realization extraction their probe microscope pave way toward broadband spectroscopy at single-nanometer length scales, using parallel detection multiple wavelengths, for instance, transient absorption or two-dimensional spectroscopy.