Measuring topography and refractive index of channel waveguides with a hybrid AFM-SNOM
Anno: 1998
Autori: Mannoni A., Quercioli F., Tiribilli B., Ascoli C., Baschieri P., Frediani C.
Affiliazione autori: Istituto Nazionale di Ottica, Largo E. Fermi 6, 50125 Firenze, Italy;
Istituto di Biofisica CNR, 56127 Pisa, Italy
Abstract: An hybrid atomic force-scanning near-field optical microscope (AFM-SNOM) has been realized starting from a home-built AFM. The instrument uses a tetrahedral SIN tip for force and near field detection and is designed to provide, besides simple imaging, a full three-dimensional (3-D) mapping of force, friction and light intensity on the sample. High-resolution optical images of dielectric samples are presented together with curves describing the behavior of the collected optical intensity as a function of tip-object distance. AFM images and force-distance curves are reported as well and are compared with those obtained from the optical channel. Subwavelength features of the samples can be easily appreciated in both kinds of images, and the refractive index of the object can he computed from the attenuation constant of the tunneling light detected by the tip, with the AFM curve providing a convenient way of detecting the contact point. The spatial resolution of this kind of measurement is far better than that obtainable with any other index-measuring device. Homogeneous glass samples as well as monomode channel waveguides were analyzed in our experiments. The refractive index of several different prisms, made either of BK7 (n = 1.519 at lambda = 532 nm) or of SF58 (n = 1.932) glass, could be measured with our near-field technique. As for the channel waveguides, the accuracy of our measurements lets us detect their presence and lateral extension in the substrate but is not yet sufficient to allow the reconstruction of their index profile.
Giornale/Rivista: JOURNAL OF LIGHTWAVE TECHNOLOGY
Volume: 16 (3) Da Pagina: 388 A: 394
Parole chiavi: Atomic force microscopy; Communication channels (information theory); Electromagnetic wave attenuation; Image quality; Object recognition; Optical communication; Optical microscopy; Refractive index, Channel waveguides; Scanning near field optical microscopy (SNOM), Optical waveguidesDOI: 10.1109/50.661365Citazioni: 8dati da “WEB OF SCIENCE” (of Thomson Reuters) aggiornati al: 2024-04-28Riferimenti tratti da Isi Web of Knowledge: (solo abbonati) Link per visualizzare la scheda su IsiWeb: Clicca quiLink per visualizzare la citazioni su IsiWeb: Clicca qui