Grupo de Optoelectrónica

Permanent URI for this collectionhttp://48.217.138.120/handle/20.500.12272/1239

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Now showing 1 - 4 of 4
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    Accuracy and Mechanistic Details of Optical Printing of Single Au and Ag Nanoparticles
    (2017-08-30) Cerrotta, Santiago; Garjiulo, Julian; Violi, Lanina; Chvatal, Lukas; Cortes, Emiliano; Perassi, Eduardo; Diaz, Fernando; Zemánek, Pavel; Stefani, Fernando D.;
    Optical printing is a powerful all-optical method that allows the incorporation of colloidal nanoparticles (NPs) onto substrates with nanometric precision. Here, we present a systematic study of the accuracy of optical printing of Au and Ag NPs, using different laser powers and wavelengths. When using light of wavelength tuned to the localized surface plasmon resonance (LSPR) of the NPs, the accuracy improves as the laser power is reduced, whereas for wavelengths off the LSPR, the accuracy is independent of the laser power. Complementary studies of the printing times of the NPs reveal the roles of Brownian and deterministic motion. Calculated trajectories of the NPs, taking into account the interplay between optical forces, electrostatic forces, and Brownian motion, allowed us to rationalize the experimental results and gain a detailed insight into the mechanism of the printing process. A clear framework is laid out for future optimizations of optical printing and optical manipulation of NPs near substrates.
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    Room evacuation through two contiguous exits
    (Physica A: Statistical Mechanics and its Applications, 2017-05-15) Sticco, Ignacio; Frank, Guillermo; Cerrotta, Santiago; Dorso, Claudio
    Current regulations demand that at least two exits should be available for a safe evacuation during a panic situation. Although the "faster is slower" effect is expected to take place near the exits, the evacuation time will improve because of the additional exits. However, rooms having contiguous doors not always reduce the leaving time as expected. We investigated the relation between the doors separation and the evacuation performance. We found that there exists a separation distance range that does not really improve the evacuation time, or it can even worsen the process performance. To our knowledge, no attention has been given to this issue in the literature. This work reports how the pedestrians dynamics differ when the separation distance between two exit doors changes and how this affects the overall performance.
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    Feasibility and analysis of a system of two in tandem interferometers for optical coherence tomography
    (IEE Explore Digital Library, 2017-12-18) Cerrotta, Santiago; Morel, Eneas Nicolás; Alvira, Fernando; Torga, Jorge Román
    A signal obtained from a combined system of two interferometers of low coherence in the frequency domain is presented and analyzed. This system allows to expand the range of measurement offered by the conventional optical tomography system of a single interferometer with a spectrometer as a detector.
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    Large Axial Range Frequency-Domain Optical Low Coherence Interferometry
    (2019-01-15) Cerrotta, Santiago; Morel, Eneas Nicolás; Alvira, Fernando; Torga, Jorge Román
    In this paper, we propose a new experimental setup to extend the measurement range of frequency-domain low coherence interferometry (FD-LCI) from 3 mm to 2 cm. The FD-LCI can be extended to the technique of frequency domain optical coherence tomography (FD-OCT) by performing additional lateral scanning. This new and simple arrangement just attaches an extra interferometer before the spectrometer in a typical FD-LCI setup. With this configuration, it is possible to overcome the limitation of the dynamic range of the conventional technique. This allows us to measure the optical path difference of the sample of interest, which is outside the detection range of the spectrometer, using an extra interferometer as a tuner system. In addition, this tuning allows significant minimization of the effects produced by the fall-off. The accuracy of the new system is obtained by adding the FD-LCI and the tuning micrometric translator accuracies. In our experimental setup, this value is 20 μm.