Lia Maria Zerbino

Spatial partial coherence in Young's interferograms

Youngs interferograms with high visibility reveals a high degree of spatial coherence of first order. But, spatially partial coherence of second order can be observed when it interferes itself through a compensated Michelsons interferometer attached at the exit of the Youngs slit pair. We show that the patterns at the exit of the Michelsons interferometer are Youngs interferograms with modulation fringes, which allow an estimation of the degree of the high order spatial coherence.

Optomechatronic Techniques to Characterize the Topography of a MW Satellite Antenna

We describe several optomecatronic techniques to characterize the topographic changes due to thermomechanical deformations of models of an off‐set MW satellite antenna. The surface of the antennas is a paraboloidal torus. This type of antenna will be installed in the SAC‐D/AQUARIUS Satellite Mission; this mission is a collaboration between the NASA from the USA and the Comision Nacional de Actividades Espaciales (CONAE), Argentina. Two antennas will serve at 23.8 GHz and 36.5 GHz radiometers to study the global water cycle by analyzing various geophysical parameters. The used optomecatronic techniques were Structured illumination (SI), Differential Structured Illumination (DSI), Moire Profilometry (MP), and Fourier Transform Profilometry (FTP). The temporal changes of temperature and the spatial thermal gradients were recorded by using Infrared Thermography (IRT). Optical measurements were compared with those obtained by a mechanical dial indicator. The quality of the mechanical measurements is of the ord...

Optical direct observation of Gouy phase shift

This paper considers the anomalous propagation of phase through the focus of an optical system. We observed the interference rings produced by two collinear spherical waves coming from the same laser source with different focal points. Then three regions are determined along the optical axis: R1, befor focuses; R2 between focuses; and R3, after focuses. In each of them we pictured interference rings which are complementary in intensity with a CCD camera. The complemnetary relationship is caused by the sudden change of phase by π through each focus.

Young interference through transparent plane parallel plates

This paper presents an analysis of Young figures of interference generated by the field coming from two coherent, point, and near one to the other sources, which propagate through a transparent parallel plane plate. The cases in which the plate adopts different orientations in space were considered.

Analysis of a Young Michelson tandem interferometer

In a Young-Michelson tandem interferometer a Michelson interferometer is illuminated through a pair of Young slits. The pattern produced by this set-up is analyzed theoretically. The consequences of small misalignments and uncompensated arms in the Michelson interferometer are studied. The effects of the spatial and temporal partial coherence of the source are also explored. Experimental result using a laser source are shown to be in good agreement with the predicted theoretical calculations.

Partially coherent effects in Young-Michelson's interferograms

Youngs interferograms with high visibility reveals a high degree of spatial coherence. However, effects due spatially partial coherence can be observed when a Youngs interference pattern interferes itself through a compensated Michelsons interferometer, which is attached at the exit of the Youngs slit pair, as we show in this paper.

Optical interferential confined free meniscus liquid level

This paper demonstrates a newly experimental solution to obtain flat free surfaces of confined liquids in small containers and a useful approach to build-up an optical level of very small dimensions.

Optical interferometric studies of a confined liquid free surface: meniscus-effect compensation and time evolution of the surface

A fruitful approach to the studies of a liquid free surface is demonstrated. Using optical interferential techniques, the free surface of nonvolatile and volatile confined liquids is analyzed. Various wall container types are investigated. Besides the classical plane wall, experiments are performed by using cylindrical and toroidal walls. In these last cases, the meniscus effect that affects the free surface of the liquid is compensated. Then, it is possible to obtain completely flat free surfaces of liquids up to 80% of their total. Interferometric experiments are also described to measure the inclination of the site with respect to the local horizon, represented by the liquid flat free surface, and to follow the temporal evolution of such free surfaces affected by different conditions.

Interference profiles with multiple spherical waves: general case

Characteristics of multiple-beam interference fringes, as in a Fabry–Perot interferometer with monochromatic light, are analyzed. The optical path and the optical-path difference between interfering beams are calculated for the most general case. Different refractive indices in the inner and outer media, and arbitrary locations of the light source and the point of observation, are taken into account. An expression for the impulse response of the system is given. The results obtained from experimental tests confirm the theoretical predictions.

Application of Vertical Brackets in Orthodontic Treatments: A Laser Speckle Study

This paper reports the application of a laser speckle technique to orthodontic studies. The purpose of these studies is to certify the validity of a proposal related with a new type of apparatus, and the methodology to be used in orthodontic treatments.