Frans B Segerink

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The monoclinic double tungstate crystals are good candidates as host materials for rare-earth ions. Thanks to their crystalline nature, clustering of doping ions is avoided. High concentrations of active ions can therefore be achieved, which, together with the large absorption and emission cross sections of the active ions in these materials, leads to(More)
An evanescent field optical microscope (EFOM) is presented which employs frustrated total internal reflection on a localized scale by scanning a dielectric tip in close proximity to a sample surface. High resolution images of dielectric gratings and spheres containing both topographic and dielectric information have been obtained. The resolution obtained is(More)
Surface plasmon polaritons are electromagnetic waves that propagate tightly bound to metal surfaces. The concentration of the electromagnetic field at the surface as well as the short wavelength of surface plasmons enable sensitive detection methods and miniaturization of optics. We present an optical frequency plasmonic analog to the phased antenna array(More)
±1 is characteristic of the C±N stretching mode in the QBB moiety, [11] where Q and B denote the quinoid and benzenoid rings, respectively. The 1310 cm ±1 peak, apart from showing a red shift to 1300 cm ±1 , gains substantial intensity. Along with this, a new feature appears at 1240 cm ±1 , which is assigned to C±N + stretching in the BBB moiety. We notice(More)
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