Estudio de distribuciones de Speckles modulados y aplicaciones

Facultad de Ciencias Exacta

Talbot and Lau phenomena implementation via a photorefractive converter

We propose a novel implementation of the Lau and Talbot effects. It employs a grating registered as modulation of birefringence in a Bi12SiO20 crystal. The systems proposed allow to control the visibility and in particular to reverse the contrast of the self images and Lau fringes by rotating an analyzer. A theoretical approach is outlined and the predicted behavior is confirmed by results obtained under different experimental conditions. We have taken advantage of the arrangements to demonstrate some applications.CONICETPICT 0041Fundación Antorchas and Fac. de Ingenieria UNLP, ArgentinaCOLCIENCIAS,Colombi

Contrast inversion in the Lau phenomena implemented with a photorefractive grating

It was implemented the Lau effect with a grating registered in a BSO crystal. Two different arrangement were analyzed. In both cases, it is possible to control the visibility and to produce the contrast inversion of fringes, by properly setting the pass plane orientation of an analyzer located at the crystal output.CONICETFundación AntorchasFacultad de ingeniería U.N.L.PCOLCIENCIAS (Colombia

¿Qué es la luz?

Este documento incluye un texto que responde la pregunta planteada en el título, un mapa de contenidos y una guía metodológica para la realización de un taller. En el texto se aborda la pregunta “¿Qué es la luz?”, a partir de situaciones de la vida cotidiana que nos permiten identificar la necesidad de la existencia de la luz para ver los objetos, posteriormente se hace un breve recorrido histórico sobre las diferentes teorías sobre la luz, y se centra en la explicación de dos de ellas: la teoría corpuscular y la teoría ondulatoria

Analysis of vibrations in a plate using interferometric methods

In this work some frequencies and modes of vibration of a thin plate were determined using interferometric methods like: real-time holographic interferometry, time-average holographic interferometry, digital speckle pattern interferometry DSPI. And the results obtained are compared with those obtained with the program of finite elements COSMOS.Universidad EAFI

Speckle interferometric technique to assess soap films

An 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 reservedCONICET, CICPBA, Fundaci on Antorchas, Faculty of Engineering of the National University of La Plata (Argentina) and the financial support of ICTP-TRIAL Programm,Trieste, Italia

Speckle photography through different multiaperture pupils

An image multiplexing method based on the internal modulation of speckle grains by employing different multiple aperture pupils for recording is proposed. The interferometric fringes profile and visibility in the Fourier plane, for uniform in-plane displacement double- exposed specklegrams through different pupils recording, are analyzed in terms of the geometric parameters of the pupils. Experimental evidences are presented.CONICET PICT 0041CICPBAFundación AntorchasFacultad de ingeniería U.N.L.PCOLCIENCIAS (Colombia

Speckle photography with different pupils in a multiple-exposure scheme

The 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, 120.6160Consejo Nacional de Investigaciones Científicas y Técnicas, Comisión de Investigaciones Científicas de la Provincia de Buenos Aires, Faculty of Engineering, National University of La Plata (Argentina).Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina) and Instituto Colombiano para el Desarrollo de la Ciencia y la Tecnología, ‘‘Fransisco José de Caldas’’ (Colombia)

Double aperture speckle method using a BSO crystal for in plane displacement

SPIE Proceedings Vol. 3572The possibility of using a BSO crystal as a recording medium of specklegrams with carrying frequency fringes, to storage multiple interferograms, for uniform in-plane displacements, is presented. Experimental results are shown.CONICET (Argentina)FundaciOn Antorchas (Argentina)CICPBA (Argentina)Facultad de Ingenierla Universidad Nacional de La Plata (Argentina)COLCIENCIAS (Colombia

Tiempo para quedar en embarazo e infertilidad entre mujeres ocupacionalmente expuestas a plaguicidas en empresas floricultoras de la sabana de Bogotá

IP 1101-04-10162ANEXOS: Time to first pregnancy among women working in agricultural production; Concepcion retrasada en una poblacion de mujeres horticultoras; Desarrollo y validacion deuna metodologia analitica para la determinacion de etilentiourea en orina y parches dermicos empleando cromatografia liquida de alta eficiencia; Analisis de sobrevida para determinar la asociacion entre expocicion aplaguicidas enempresas floricultoras y tiempo para quedar en embarazo; Exposicion a plaguicidas y aborto espontaneoen el primer embarazo en una poblacion colombiana; Reporte parcial de actividades de internado especialjunio 4 de 2001 a diciembre 2 de 2001; Time to firts pregnancy among women working in intensive agriculturalproduction in columbia.ARTICULO(S) EN REVISTA: Implementacion y validacion de unametodologia analitica para la determinacion de;etilenourea en orina y parches dermicos / Angela Viviana BarretoCharry, Ana Lucia Castiblanco Rodriguez,;Stella Ospina de Nigrinis, Alvaro Javier Idrovo. -- En: Revistacolombianade ciencias quimico farmaceuticas.; Vol. 32, no. 1 (2003); p. 1-5. -- PONENCIA(S) EN CONGRESO:Tiempo paralograr el primer embarazo entre;mujeres horticultoras colombianas / Alvaro J., Idrovo, LuzHelena Sanin, Donald Cole, Jorge Chavarro, Heidy;Caceres, Javier Narvaez, Mauricio Restrepo. -- En: Congreso deinvestigacion en salud publica (10 : 2003 mar.;5-7 : Cuernavaca Moleros, Mexico)