Examinando por Autor "Giraldo, L.M."

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    Ítem
    Diffraction efficiency adjustment to record high quality color holograms
    (Universidad EAFIT, 2015-08-06) Velásquez, D.; Giraldo, L.M.; Universidad EAFIT; Karlsruhe Institute of Technology
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    Ítem
    Monocolor and color holography of pre-Hispanic Colombian goldwork: A way of Colombian heritage appropriation
    (SPIE-INT SOC OPTICAL ENGINEERING, 2018-01-01) Madrid Sánchez, A.; Giraldo, L.M.; Velásquez Prieto, D.; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
    Optically indistinguishable copies of 3D real objects or holograms are known to be suitable to replace exhibited artistic pieces in museums. In this paper, we discuss holography as an alternative to protect, share and preserve finely crafted gold pieces belonging to the indigenous treasure inherited by Colombians. We present high diffraction efficiency monocolor and color holograms of native goldwork. As reference objects and proof of concept, we use replicas of the renowned and emblematic Poporo Quimbaya, pre-Hispanic gold pendants and anthropomorphic gold pieces. We report experimental details to deal with different types of commercial holographic recording materials, as for example, PFG-03M and PFG- 03C silver halides or C-RT20 photopolymers. And its general feasibility for reproducing high-quality holograms suitable for museum exhibitions or traveling art-collections. Copyright © 2018 SPIE. Downloading of the abstract is permitted for personal use only.
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    Ítem
    Obtaining relief structures in silver halide materials
    (Sociedad Espanola de Optica, 2013-01-01) Giraldo, L.M.; Velásquez, D.; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
    Diffraction transmission gratings were recorded in AGFA-8E75 film, chemically treated under processes with D-19 + potassium ferrocyanide and a chemical processing technique proposed for PE-2 film to obtain embossed stripes. Holographic structures were measured topographically by the technique of atomic force microscopy in noncontact mode (NC-AFM) and we observe changes in the depths under variations in exposures and used photochemistry. We find that the best performance in terms of relief depth obtained is given by the conventional process which reached depths between 0.15 µm and 0.3 µm for spatial frequencies of the order of 400