Focusing surface plasmons on Er3+ ions through gold planar plasmonic lenses

• Published in: Applied physics. A, Materials science & processing Materials science & processing, 2012-12, Vol.109 (4), p.1037-1041
• Main Authors: Rivera, V. A. G., Ferri, F. A., Nunes, L. A. O., Zanatta, A. R., Marega, E.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Collective excitations (including excitons, polarons, plasmons and other charge-density excitations); Condensed Matter Physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Lenses, prisms, and mirrors; Machines; Manufacturing; Nanotechnology; Optical and Electronic Materials; Optical elements, devices, and systems; Optics; Physics; Physics and Astronomy; Processes; Surface and interface electron states; Surfaces and Interfaces; Thin Films
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-012-7374-8

Gold plasmonic lenses consisting of a planar concentric rings-groove with different periods were milled with a focused gallium ion beam on a gold thin film deposited onto an Er 3+ -doped tellurite glass. The plasmonic lenses were vertically illuminated with an argon ion laser highly focused by means of a 50× objective lens. The focusing mechanism of the plasmonic lenses is explained using a coherent interference model of surface plasmon-polariton (SPP) generation on the circular grating due to the incident field. As a result, phase modulation can be accomplished by the groove gap, similar to a nanoslit array with different widths. This focusing allows a high confinement of SPPs that can excite the Er 3+ ions of the glass. The Er 3+ luminescence spectra were measured in the far-field (500–750 nm wavelength range), where we could verify the excitation yield via the plasmonic lens on the Er 3+ ions. We analyze the influence of the geometrical parameters on the luminescence spectra. The variation of these parameters results in considerable changes of the luminescence spectra.