Optical nanofibers and spectroscopy

We review our recent progress in the production and characterization of tapered optical fibers with a sub-wavelength diameter waist. Such fibers exhibit a pronounced evanescent field and are therefore a useful tool for highly sensitive evanescent wave spectroscopy of adsorbates on the fiber waist or of the medium surrounding. We use a carefully designed flame pulling process that allows us to realize preset fiber diameter profiles. In order to determine the waist diameter and to verify the fiber profile, we employ scanning electron microscope measurements and a novel accurate in situ optical method based on harmonic generation. We use our fibers for linear and non-linear absorption and fluorescence spectroscopy of surface-adsorbed organic molecules and investigate their agglomeration dynamics. Furthermore, we apply our spectroscopic method to quantum dots on the surface of the fiber waist and to caesium vapor surrounding the fiber. Finally, towards dispersive measurements, we present our first results on building and testing a single-fiber bi-modal interferometer.Comment: 13 pages, 18 figures. Accepted for publication in Applied Physics B. Changes according to referee suggestions: changed title, clarification of some points in the text, added references, replacement of Figure 13

Miniaturisierter Vielkanalanalysator-Modul Schlussbericht

Available from TIB Hannover: DtF QN1(58,51) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

A new IAEA Technical Report Series Handbook on Radionuclide Transfer to Wildlife

The IAEA Technical Report Series (TRS) handbook on transfer of radionuclides to human foodstuffs from terrestrial and freshwater systems has recently been revised during the EMRAS I programme [1]. The document updates the previous handbook (TRS 364) and constitutes an important source of information for transfer parameters for the human foodchain. Quantification of the rates of transfer of radionuclides through foodchains to humans has long been a key focus of radiation protection. More recently, there has been a move away from radiation protection being solely anthropogenic to one which also considers protection of the environment as recognised by both the IAEA [2] and the ICRP [3] in their Fundamental Safety Principles and revised Recommendations, respectively, both of which now include the need to protect the environment. To address these recommendations and safety principles, the consequences of radiological releases need to be considered in part by estimating an internal dose. To do this, the transfer of radionuclides to wildlife of interest needs to be quantified. In response to the need for a reference source of information on radionuclide transfer to wildlife, the IAEA initiated the development of a TRS handbook, which has been supported by interaction with the EMRAS II Working Group 5, (http://www-ns.iaea.org/projects/emras/emras2/working-groups/working-group-five.asp). The TRS handbook has been finalised and is currently going through the IAEA approval process. The TRS handbook provides equilibrium concentration ratio values for wildlife groups in terrestrial, freshwater, marine and estuarine environments. Wildlife is considered to include all non-domesticated plants, animals and other organisms including feral species (i.e. non-native self-sustaining populations). The TRS handbook provides IAEA Member States with transfer data for use in the radiological assessment of wildlife as a consequence of planned and existing exposure situations [3]. As an equilibrium approach is presented, these data are not directly applicable to emergency situations