NEAR-FIELD OPTICS - MICROSCOPY WITH NANOMETER-SIZE FIELDS

The electromagnetic fields that can build up around metallic or dielectric pointed tips are of increasing interest in context with the new scanning probe microscopies (tunneling, near-field optics, Coulomb and van der Waals forces etc.). The paper presents exact solutions of Laplace's equations for the tip/sample geometry. For suitable media, plasmons are found whose electric fields are highly localized in the gap region. We believe that the field enhancement associated with such tip plasmons is instrumental for inelastic tunneling and light emission during scanning tunneling microscopy.