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Ítem Phase stepping in Lau interferometry(Elsevier, 1999-06-15) Ángel-Toro, Luciano; Tebaldi, Myrian; Henao, Rodrigo; Ángel-Toro, Luciano; Tebaldi, Myrian; Henao, Rodrigo; Universidad EAFIT. Departamento de Ciencias Básicas; langel@eafit.edu.co; Óptica AplicadaThe implementation of phase shifting interferometry to analyze the Lau interferometric fringe patterns is proposed. The fundamentals of this application are theoretically discussed and the basis of the phase map interpretation is outlined. The three steps algorithm is used to depict the phase maps of lens-like test objects and an application for measuring focal lengths of lenses is reported. Experimental results are presented. q1999 Elsevier Science B.V. All rights reserved.Ítem 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 Interpretación Cuantitativa de Interferogramas Holográficos por Medición de la Fase(Sociedad Colombiana de Física, 2000-01-01) Velásquez, Daniel Ignacio; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaÍtem Optical processing by fringed speckles registered in a BSO crystal(SPIE, 2000-01-01) Tebaldi, M.; Toro, L.A.; Trivi, M.; Bolognini, N.; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaAn alternative image multiplexing technique, employing a multiple-aperture pupil for each exposure, is presented. The aperture arrangement of the pupil is modified between exposures. A thick photo-refractive BSO crystal is used as recording material. The technique allows concentrating the spectral components of a pair of images selectively into isolated spots in the Fourier plane. Two applications are proposed, in image processing and optical metrology.Ítem Speckle photography with different pupils in a multiple-exposure scheme(OPTICAL SOC AMER, 2000-01-01) Angel, L; Tebaldi, M; Bolognini, N; Trivi, M; 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.Ítem Optical processing by fringed speckles registered in a BSO crystal(SPIE, 2000-07-28) Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Ángel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Ángel-Toro, Luciano; Universidad EAFIT. Departamento de Ciencias Básicas; langel@eafit.edu.co; Óptica AplicadaAn alternative image multiplexing technique, employing a multiple-aperture pupil for each exposure, is presented. The aperture arrangement of the pupil is modified between exposures. A thick photorefractive BSO crystal is used as recording material. The technique allows concentrating the spectral components of a pair of images selectively into isolated spots in the Fourier plane. Two applications are proposed, in image processing and optical metrology. © 2000 Society of Photo-Optical Instrumentation Engineers. © 2000 Society of Photo-Optical Instrumentation EngineersÍtem New multiple aperture arrangements for speckle photography(ELSEVIER SCIENCE BV, 2000-08-01) Tebaldi, M; Toro, LA; Trivi, M; Bolognini, N; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaWe propose a multiple exposure specklegram by using an optical system whose multiple aperture pupil changes between exposures. In particular, we analyze experimentally two arrangements and we show that it is possible to store the required information by employing a minimum number of registers if an adequate selection of the pupil is done. We study the effect of the decorrelation (among the stored speckle pattern) introduced by changing the multiple aperture pupil arrangements between exposures. The fundamentals and the relative benefits of the new scheme proposed are discussed on the basis of a fringe visibility analysis. © 2000 Published by Elsevier Science B.V.Ítem New multiple aperture arrangements for speckle photography(Elsevier B.V, 2000-08-01) Angel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Angel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Universidad EAFIT. Departamento de Ciencias Básicas; Angel-Toro, Luciano (langel@eafit.edu.co); Óptica AplicadaAbstract. We propose a multiple exposure specklegram by using an optical system whose multiple aperture pupil changes between exposures. In particular, we analyze experimentally two arrangements and we show that it is possible to store the required information by employing a minimum number of registers if an adequate selection of the pupil is done. We study the effect of the decorrelation (among the stored speckle pattern) introduced by changing the multiple aperture pupil arrangements between exposures. The fundamentals and the relative benefits of the new scheme proposed are discussed on the basis of a fringe visibility analysis.Ítem Double exposure specklegrams obtained by using scaled aperture pupils(SPIE-INT SOC OPTICAL ENGINEERING, 2001-01-01) Angel, L; Tebaldi, M; Trivi, M; Bolognini, N; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaIn speckle photography the pupil aperture is usually not modified between exposures. In our work, the change of the pupil aperture scale between exposures is analysed on the basis of double-exposed image speckle, before and after a diffuser inplane displacement is done. The apertures have the same shape but its scale is modified between exposures. Note that the relative position of the aperture is maintained. In particular, we analyse a simple case that uses a circular aperture whose diameter is modified for recording each image. The intensities in the image plane and the fringe visibility are evaluated, in terms of the geometric characteristics of the pupils. © 2001 SPIE · 0277-786X/01/$15.00.Ítem Propierties of speckle patterns generated through multiaperture pupils(Elsevier, 2001-05-15) Ángel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Ángel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Universidad EAFIT. Departamento de Ciencias Básicas; Ángel-Toro, Luciano (langel@eafit.edu.co); Óptica AplicadaThe characteristics of the image speckles obtained through multiple aperture pupils are theoretically analyzed in terms of the parameters defining the pupils. The possibility of interpreting and synthesizing the image speckle distribution in terms of rather elementary structures is considered, based on the Fourier optics analysis. Then, first and second order statistical properties of the speckle patterns are studied by evaluating both the mutual intensity and the auto-correlation intensity of speckle distributions obtained by means of pupils consisting of identical apertures. Experimental results are presented to confirm the analysis.Ítem Properties of speckle patterns generated through multiaperture pupils(ELSEVIER SCIENCE BV, 2001-05-15) Angel, L; Tebaldi, M; Trivi, M; Bolognini, N; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaThe characteristics of the image speckles obtained through multiple aperture pupils are theoretically analyzed in terms of the parameters defining the pupils. The possibility of interpreting and synthesizing the image speckle distribution in terms of rather elementary structures is considered, based on the Fourier optics analysis. Then, first and second order statistical properties of the speckle patterns are studied by evaluating both the mutual intensity and the auto-correlation intensity of speckle distributions obtained by means of pupils consisting of identical apertures. Experimental results are presented to confirm the analysis. © 2001 Published by Elsevier Science B.V.Ítem Recuperación de la energía radiada por conductores de corriente alterna(Sociedad Colombiana de Física, 2001-06-01) Marulanda, José Ignacio; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaÍtem Fringe visibility analysis with different scale apertures in speckle photography(TAYLOR & FRANCIS LTD, 2001-09-15) Angel, L; Tebaldi, M; Trivi, M; Bolognini, N; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaThe use of different scale aperture pupils for image recording in speckle photography is analysed. In particular a double-exposure specklegram is considered. The ensemble-average intensity in the Fourier plane is analytically derived and fringe visibility is investigated. The theoretical results are verified by in-plane displacement translation experiments.Ítem Phase-object detection by use of double-exposure fringe-modulated speckle patterns(OSA, 2003-01) Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Angel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor; Angel-Toro, Luciano; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaWe study the properties of a double-exposure image specklegram of a diffuse object obtained by use of a doubleaperture pupil. A phase object is placed in front of one aperture during the first or the second exposure. Also, it is assumed that a uniform displacement of the diffuser between exposures is produced. The recorded specklegram is coherently illuminated and analyzed by Fourier transform operations. The average intensity distribution and the interference fringe visibility in the Fourier plane are investigated. On this basis, an alternative interference technique to detect phase objects is proposed.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 interferometric technique to assess soap films(ELSEVIER SCIENCE BV, 2004-01-02) Tebaldi, M; Angel, L; Bolognini, N; Trivi, M; Universidad EAFIT. Departamento de Ciencias Básicas; 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 reserved.Ítem EMIR: the GTC NIR multi-object imager spectrograph(SPIE-INT SOC OPTICAL ENGINEERING, 2004-09-01) Garzón, Francisco; Abreu, David; Barrera, Sonia; Correa, Santiago; Díaz, Jose; Fragoso, Ana; Fuentes, F.J; Gago, Fernando; Gonzalez, Carlos; López, Pablo; Manescau, Antonio; Patrón, Jesus; Pérez, Jaime; Redondo, Pablo; R. Restrepo; Sánchez, Vicente; Villegas, Alejandro; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaWe present the final global design and performances of EMIR, the NIR multi-object spectrograph of the GTC, as well as the plan for its early scientific exploitation.Ítem EMIR mechanical design status(SPIE-INT SOC OPTICAL ENGINEERING, 2004-09-01) Fuentes, F. J; Sánchez, Vicente; Barrera, Sonia; Correa, Santiago; Pérez, Jaime; Redondo, Pablo; R. Restrepo; Tenegi, Fabio; Villegas, Alejandro; Patrón, Jesus; Garzón, Francisco; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaEMIR is the NIR multi-object imager and spectrograph for the GTC (Gran Telescopio Canarias). The instrument PDR phase was held successfully in March 2003, and we are at present in the middle of the ADR (Advanced Design Phase) during which a number of mechÍtem EMIR optomechanics(SPIE-INT SOC OPTICAL ENGINEERING, 2004-09-01) Barrera, Sonia; Villegas, Alejandro; Fuentes, Javier; Correa, Santiago; Pérez, Jaime; Redondo, Pablo; R. Restrepo; Sánchez, Vicente; Tenegi, Fabio; Garzón, Francisco; Patrón, Jesus; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaEMIR is a NIR multiobject spectrograph with imaging capabilities to be used at the GTC. A general description of instrument performances, as well as the updated optical and mechanical layouts, can be found elsewhere on these proceedings.Ítem Structural and thermal analysis of EMIR(SPIE-INT SOC OPTICAL ENGINEERING, 2004-09-30) Correa, Santiago; R. Restrepo; Tenegi, Fabio; Fuentes, F.J; Sanchez, Vicente; Barrera, Sonia; Pérez, Jaime; Redondo, Pablo; Villegas, Alejandro; Garzón, Francisco; Patrón, Jesus; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaThis paper shows the different design concepts and techniques employed in the structural and thermal analysis of EMIR (Espectrografo Multiobjeto Infrarrojo), nowadays under development at the Instituto de Astrofisica de Canarias.