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Examinando Artículos por Autor "Ángel Toro, Luciano"
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Ítem Speckle interferometric technique to assess soap films(Elsevier B.V., 2003-10-17) Ángel Toro, Luciano; Bolognini, Néstor Alberto; Tebaldi, Myrian Cristina; Trivi, Marcelo Ricardo; Universidad EAFIT. Departamento de Ciencias Básicas; langel@eafit.edu.co; Óptica AplicadaAn speckle interferometric technique to monitor the thinning process of vertical soap film before the film rupture is presented -- The interferometric arrangement consists in a double aperture pupil optical system which images an input diffuser -- In a first step, a reference specklegram is stored in the computer buffer memory -- Afterwards, the soap film is located in front of one pupil aperture, an uniform displacement of the diffuser is produced and a new speckle pattern is stored -- The soap film status is characterized in terms of the changes that this dynamic phase object introduces in the correlation fringes obtained by applying a FFT algorithm to the resulting summed specklegram. This procedure is done in real time as far as the soap film evolves in the successive status -- It is experimentally demonstrated that the soap film during drawing acts as a variable wedge -- The correlation fringes behavior becomes an important tool to establish the wedge shaped soap film angle and the thickness variations 2003 Elsevier B.V. All rights reservedÍtem Speckle photography with different pupils in a multiple-exposure scheme(Optical Society of America, 2000-01-01) Ángel Toro, Luciano; Bolognini, Néstor Alberto; Tebaldi, Myrian Cristina; Trivi, Marcelo Ricardo; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaThe use of different multiple-aperture pupils for recording each image in speckle photography is proposed -- The introduction of suitable spatial frequency carriers, by internally modulating imaged speckles, allows one to selectively isolate or combine the spectral content of different images into spatially separated regions in the Fourier plane -- Theoretical and experimental results extend the speckle photography technique to the depiction of several specklegrams of multiple uniform in-plane displacements -- In this case, because different pupils are considered for recording, the cross-correlation functions for the amplitudes and intensities in the image plane are calculated on the basis of the statistical properties of the object -- Also, the ensemble-average intensity in the Fourier plane is analytically derived, and fringe visibility is investigated. © 2000 Optical Society of America [S0740-3232(00)01701-4]OCIS codes: 120.0120, 120.3180, 120.3940, 120.6160Ítem Vortex metrology using Fourier analysis techniques: vortex networks correlation fringes(OSA, 2012-10-19) Ángel Toro, Luciano; Sierra Sosa, Daniel; Tebaldy, Myrian; Bolognini, Néstor; Ángel Toro, Luciano; Sierra Sosa, Daniel; Tebaldy, Myrian; Bolognini, Néstor; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaIn this work, we introduce an alternativemethod of analysis in vortexmetrology based on the application of the Fourier optics techniques. The first part of the procedure is conducted as is usual in vortexmetrology for uniformin-plane displacement determination. On the basis of two recorded intensity speckled distributions, corresponding to two states of a diffuser coherently illuminated, we numerically generate an analytical signal fromeach recorded intensity pattern by using a version of the Riesz integral transform. Then, fromeach analytical signal, a two-dimensional pseudophase map is generated in which the vortices are located and characterized in terms of their topological charges and their core’s structural properties. The second part of the procedure allows obtaining Young’s interference fringes when Fourier transforming the light passing through a diffracting mask with multiple apertures at the locations of the homologous vortices. In fact, we use the Fourier transformas amathematical operation to compute the far-field diffraction intensity pattern corresponding to themultiaperture set. Each aperture fromthe set is associatedwith a rectangular hole that coincides both in shape and size with a pixel from recorded images.We show that the fringe analysis can be conducted as in speckle photography in an extended range of displacement measurements. Effects related with speckled decorrelation are also considered. Our experimental results agree with those of speckle photography in the range in which both techniques are applicable. © 2012 Optical Society of America OCIS codes: 050.4865, 030.6140.