Grupo de Nanofotonica

Permanent URI for this collectionhttp://48.217.138.120/handle/20.500.12272/1241

Browse

Start date: 2000End date: 2009

Search Results

Now showing 1 - 7 of 7
  • Thumbnail Image
    Item
    Limitations due to the detector in the low coherence interferometry
    (2008-02-15) Morel, Eneas Nicolás; Torga, Jorge Román
    Se describirá como se generan las señales de interferometria de baja coherencia en el espacio de Fourier, se determinara las características que determinan el rango dinámico del sistema y las señales asociadas al sistema de detección y su influencia en la señal de interferencia.
  • Thumbnail Image
    Item
    Characterization of reference standards for dirt by Laser Ablation Induced Photoacoustics (LAIP)
    (2009-07-23) Orzi, D.J.O; Morel, Eneas Nicolás; Torga, Jorge Román; Ravigioni, A.N.; Bilmes, G.M
    Measurements of surface cleanliness and dirt characterization are important problems in a wide range of processes in industry and production. Standard methods are in most cases cumber some laboratory procedures that must be performed out of the production lines. Instruments and methods for clean liness determination and dirt characterization require reference standards for calibration. For that purpose we built a possible dirt reference standard (DRS) made by films of graphite greases ubjected to heat treatment for mechanical stabilization. The DRS characterization was performed by Laser Ablation Induced Photoacoustics (LAIP). The measurement of the thickness of the films was made by low-coherence interferometry.
  • Thumbnail Image
    Item
    Simple method for thickness measurement in opaque samples with a Michelson-Sagnac interferometer
    (2008-04-24) Morel, Eneas Nicolás; Torga, Jorge Román
    We present in this work a method to measure thicknesses of opaque samples. The technique combines the use of low coherence interferometry with a Michelson-Sagnac configuration. This ring set-up let us to measure both faces of the sample simultaneously. So it is possible to obtain the thickness by measuring the optical path difference between a reference and both surfaces of the sample. Experimental results up to 1mm are shown in metal gauge block. A resolution better than 10 micronswas obtained.
  • Thumbnail Image
    Item
    Fast scanner with position monitor forlargeopticaldelays
    (2001-11-01) Constantino, Santiago; Martínez, Oscar; Torga, Jorge Román; Do Campo, P.; Libertiun, A.R.
    Wepresent a new fastscansystemthatemploys a stepper motor used in a single steposcillatingmode and a position monitor devicebasedon a diode laser. Thesetupusedgeneratesdelays as large as 105 ps at 10 Hz, with 100% dutycycle. Wealso introduce a reliabledevicebasedontheshadow of a movingcutterwith a laser diode as the light source to avoidpowerfluctuationsproblems.
  • Thumbnail Image
    Item
    Wide band interferometryforthicknessmeasurement
    (2003) Constantino, Santiago; Martínez, Oscar; Torga, Jorge Román
    In thisworkwepresentthe concept of wide band interferometry as opposed to white-light interferometry to introduce a thickness measurementmethodthatgainsprecisionwhenthebandwidthisreduced to anadequatecompromise in order to avoidthedistortionsarisingfromthe material dispersion. The use of thewidestpossible band is a well established dogma whenthehighestresolutionisdesired in distance measurementswithwhite-light interferometry. Wewill show thatthe dogma fallswhenthicknessmeasurementsmust be carriedoutdue to material dispersion. In factthe precise knowledge of thefrequencydependence of therefractiveindexisessentialforadequatethicknessretrievalfromthe opticalexperiments. Thedevicewepresentisalsouseful to obtainthegroup refractiveindexthatisnecessary to calculatetheabsolutethicknessvalue. As anexample, we show thespreading of a siliconeoilon a reference surface in real time.
  • Thumbnail Image
    Item
    Molecular rotational diusion detected by dierential fluorescence energy
    (2000-03-01) Torga, Jorge Román; Marconi, Mario; Negri, Martin; Aramendia, Pedro
    In this paper, we present a complete study of the influence of the molecular rotational diffusion movement in the fluorescence signal when a sample is excited by two short pulses. The study includes the calculations of this effect for ellipsoidal molecules. Experimental results are presented that show a fluorescence behavior influenced by the molecular rotational diffusion movement with temporal characteristics that agree with our calculations.
  • Thumbnail Image
    Item
    Simultaneous measurement of deformation and thickness change in polymer films
    (2006-08-14) Torga, Jorge Román; Morel, Eneas Nicolás
    We present experimental results in deformation measurement and thickness change in polymer films employing Fourier domain interferometry. The set-up is a Michelson configuration in which interference signal betweeen light reflected from a reference arm is superposed with two reflection from the first and second interface from the film sample. Distance measurements for determination of deformation and thickness values were obtained after an inverse Fourier transform of the spectrum signal. With this configuration, measurements with 1 micron axial resolution, and 2mm dynamic range were obtained