Moire deflectometry experiment pdf

Application of the moire deflectometry on divergent laser beam to the measurement of the angle of arrival fluctuations and the refractive index structure constant in the turbulent atmosphere. In moire deflectometry and talbot interferometry, the focal length of the lens is obtained from the tilt of a moire fringe. Fringe formation we introduce a theory to describe the formation of the several different types of moire. An additive type and a multiplicative type of moire deflectometry are described. Observation methods, recording methods, dataprocessing. Effects of spherical aberrations of the mirror used in the moire system on the angular resolution of the system are investigated. Sep 29, 2009 the problem that is addressed here is the measurement of the mechanical properties of very thin, transparent films using bulge tests.

Pdf a novel method for measuring refractive index of gases and liquids is presented based on moire deflectometry. The moire deflectometry experimental setup is shown in fig. Novel applications of mtf measurements using moire deflectometry. Thus, d rv is measured for two positions u1 and u2, using a fizeau interferometer. Equipments for optical field metrology with more than 40 years of joint experience, the 2 founders use their combined knowhow to develop unique solutions for industrial needs in surface inspection and optical quality control customers generally request the companys services to help them revive outdated processes, suffering from technological stagnation generating. Illustration of a phase ec grating which has a periodic structure of rectangular type. To obtain the refraction image, the method requires a reference fringe pattern without the object. Two similar gratings g 1, g 2 with 80 lines in a centimeter are chosen for this experiment. The principle of lsd is derived from schlieren photography. This letter presents a method for the analysis of stiff density fields in which weak density gradients as well as strong ones, pointing in different directions, exist. Application of the moire deflectometry on divergent laser. Consequently, a novel approach based on the formation of a lens structure and using transmitted light is. Virelux inspection systems deflectometry metrology.

Generation and measurement of topological charge of composite laguerregaussian beams using moire deflectometry. Implementation of a talbotlau xray deflectometer diagnostic. Deferred electronic heterodyne moire deflectometry. However, in practice, the inspection of specular surfaces imposes special challenges. Moire deflectometry is a noninterferometric technique assessing the power of a lens. Moire deflectometry for measuring specular surface shapes. For an nphaseshift only n exposures are necessary instead of the common 2n exposures.

Stutman department of physics and astronomy, johns hopkins university, baltimore, md 21218. The optical element is moved vertically back and forth until a sharp image of the ceiling light is projected on the screen. The applications of the method to surface analysis include measurements of flatness, roughness, and inplane and outofplane distortions. A computerbased method for measuring the local refractive a. A grating is replaced by interference fringes to overcome the inability of the talbot pitch to change continuously. Automatic fringe detection algorithm used for moire. Laser beam is expanded and recollimated by l 1 and l 2 respectively. Pdf generation and measurement of topological charge of.

The easiest and fastest way to roughly evaluate a lens focal length is to hold it under a ceiling light. Chang 1 department of physics education, kongju national university, 182, sinkwandong, kongju, korea 2 department of physics, hannam university, 3 ojungdong, taejon 306791, korea abstract. Moire deflectometry a ray tracing alternative to interferometry. The experiment used a shortpulse laser 30100 j, 10 ps and a foil copper target as an xray backlighter source. Moire deflectometryray tracing interferometry sciencedirect. Overview of results from the national spherical torus experiment, d. Use of a phase type elongated circular grating in talbot. Pdf refractiveindex measurements by moire deflectometry. Development of software for analyzing different outputs of. The hologram is post analyzed by the moire deflectometry method, where the sensitivity, the. An experiment using laser schlieren deflectometry lsd for temperature measurements in the argon plasma jet. Moire deflectometry with a lowenergy ion beam for the aegis. Overview of various methods for measuring a lens focal length. A parameter that shows the strength of atmospheric turbulence is c n 2.

In addition, reconstruction of vortex beam with twochannel wavefront sensor was done 9. Investigation on interferencetype moire deflectometry. Automatic fringe detection algorithm used for moire deflectometry. Jan 11, 2018 moire deflectometry meaning moire deflectometry d.

All existing techniques make use of reflection from the film surface, but they can be difficult or impossible to apply to very thin, transparent films. Osa investigation of phase object trace duplication in. Publications plasma spectroscopy group johns hopkins. Its use in lens testing for determining properties such as surface microstructure, radius of curvature, thickness, aberrations, and otf optical transfer function, is demonstrated. We generally observe values of c n 2 to range from about 1012 to 1016 m23. Moire principle, illumination coding, fringe projection, deflectometry. We analyze theoretically and experimentally the selfimage of a phase. Gates and the nstx team, nuclear fusion, 49, 104016, 2009. A method for ray deflection mapping, moire deflectometry, which is fully compatible with interferometry, is described and demonstrated by numerous examples, including testing of optical components. Consequently, a novel approach based on the formation of a lens structure. We describe the experimental details and present theoretical analysis for obtaining the magnitude and the sign of nonlinear refractive index of materials, n2, using the moire fringe patterns. In the moire deflectometry method, the beam of light from the laser diode passes through the sample. Application of image processing in optical method, moire. Holographic techniques are used to freeze the deviated rays of a collimated beam traveling through a phase object.

Picosecond electron deflectometry of opticalfield ionized. In the experiment there is an asymmetry in the brightness of the sidelobes, with the one on the side of the outgoing laser being weaker, possibly due to. The effect of a circular detectors aperture size on readout was tested. Fast and accurate deflectometry with crossed fringes arxiv. At present we may say that both the online and the deferred heterodyne moire techniques may reliably be used. The device envisioned for such an experiment consists in a set of three transmission gratings with a pitch of few micrometers, associated with a high resolution imaging detector.

The talbot interferometry and the moire deflectometry. The hologram is post analyzed by the moire deflectometry method, where the sensitivity, the spatial. In a deflectometry experiment for finding the temperature distribution around a hot wire as a phase object, the trace of the wire in a moire pattern is duplicated, and it is observed that the. Fast and accurate deflectometry with crossed fringes. Deflectometry for the inspection of specular surfaces for surfaces used in the manufacturing industry or surfaces which just need to look good, such as, e.

Pdf phase object microscopy using moire deflectometry. The application of these properties to the measurement of displacements of the points of a surface intrinsic moire, contours or deflections projection moire and slopes reflection moire is discussed. Canabal 14 proposed a cross fringe pattern for moire deflectometry, with a phaseshift in two directions separately, so some pixels are always modulated with low intensity for one direction. The test involves creating a low frequency moire pattern between two periodic patterns which. Development of software for analyzing different outputs of a plasma jet moire deflectometry moire deflectometry is an efficient method of plasma characterization. An automatic fringe detection algorithm applied to moire deflectometry is presented. The heterodyne moire deflectometry is a conceptually simple and potentially very accurate and sensitive method for measuring deflection angles of light rays. The theory is analysed and the features are discussed with examples. Development of software for analyzing different outputs of a. Liu et al fast, accurate deflectometry using crossed fringes components by a lateral shift of the pattern in only one dimension. Holographic moire deflectometrya method for stiff density. Atmospheric turbulence characterization and wavefront sensing. Measurement of nonlinear refraction of dyes doped liquid.

The paper focuses on the moire phenomenon as a tool of experimental mechanics. Section 7, a summary, compares moirdeflectometry to related techniques and discusses the inherent limitations of the method. Through a fringe pattern which describes the height or deformation contours of the surface. In this method, moire phenomena produced by two pairs of ronchi gratings are utilized to measure the normal vector distribution of a surface under examination. Phase measuring deflectometry pmd acquires the two components of the local surface gradient via a sequence of two. If the object o is close to the front focal point, the beam coming out of the lens is almost collimated and rv is very large. Pdf moire deflectometry ray tracing interferometry. Development and implementation of talbotlau xray deflectometry m. A projection screen the floor, or the surface table is under the lens. Osa xray moire deflectometry using synthetic reference images. Bulge testing transparent thin films with moire deflectometry. Moire deflectometry, which is based on wave front analysis and geometric optics is used. Moire deflectometry with a lowenergy ion beam for the. Moire deflectometry is a versatile technique for measuring various properties of surfaces and transparent objects.

Investigation on interferencetype moire deflectometry investigation on interferencetype moire deflectometry liao, zhaoshu 19930922 00. Nonlinear refraction measurements of materials using the. Ilana glatt an introduction to moire technology, the physics behind it and its applications to optics, providing background information on the development of moire methodology, and comparing moire analysis with. It is shown that the spatial phase variations, observed when scanning along a straight moire fringe, may considerably be reduced. The sensitivity of the moire deflectometry can be easily tuned to suit the requirement of an experiment by varying the gratings pitch and their distance where the diffraction effects are allowed.

Prototype high resolution multienergy soft xray array for nstx. In a transparent mixture, change in concentration, for a multicomponent liquid mixture, and temperature, results a change in the liquid index of. Oct 01, 2014 1990 movie describing the first commercial deflectometer by rotlex. In this study, a new method for measuring the nonlinear refractive index of materials using the moire deflectometry is reported. Moire deflectometry, a method for ray deflection mapping, is described. A talbotlau xray deflectometer txd was implemented in the omega ep laser facility to characterize the evolution of an irradiated foil ablation front by mapping electron densities 10 22 cm.

Annual report october 1989 final electronic heterodyne moire. Moire deflectometry with a lowenergy ion beam for the aegis experiment. A moire deflectometry without the talbot effect is presented. Canabal 14 proposed a cross fringe pattern for moire. Moire deflectometry for measuring 3d specular surface profiles is presented in this paper. The heterodyne moire method has been studied extensively both theoretically and experimentally in two modes of operation, namely the onllne modei3 and the deferred mode45. Moire deflectometry produces result that appears similar to an interferometry technique, in which the object to be tested either phase object or specular surface is mounted in the course of a collimated beam followed by a pair of transmission gratings placed at a distance from each other. The instrument is not in production, but still it is a good introduction to moire deflectometry. Pdf determination of the focal length of nonparaxial. In this paper, electronic heterodyne moire deflectometry and electronic heterodyne holographic interferometry are compared for the. A method based on the fresnel diffraction of light from the phase step is introduced for measuring effective focal length efl and back focal length bfl of optical imaging systems.

The effect of object diffusivity on the mtf measured in a moire deflectometer is discussed and demonstrated. Moire patterns of two different elongated circular. The diffusive mtf can be isolated and measured independently of diffraction effects. This could be avoided by introducing an extra nshift for each direction with a. General disclaimer one or more of the following statements. High values of c n 2, 10 m23 or greater usually indicate a highly turbulent atmosphere. An experiment was carried out to measure the absolute. Our study shows that, in order to avoid artifacts, the reference pattern must be exactly matched in phase with the object fringe pattern. This thesis focuses on testing such a device with a lowenergy ion beam, enabling one to measure simultaneously the magnitude of surrounding electric and magnetic fields. Laser schlieren deflectometry lsd is a method for a highspeed measurement of the gas temperature in microscopic dimensions, in particular for temperature peaks under dynamic conditions at atmospheric pressure. Heterodyne holographic interferometry is better developed, and can be used with poor quality optical access to the experiment.

A microscope mode allows the detection and measurement of scratches and other imperfections. Diffusion coefficient measurements of transparent liquid. In the moire deflectometry proposed here, the distribution of angle, which is a ray deflection map of the emitted light from the source, is measured by obtaining the intensity oscillation i. Date, time, lab partners purpose of the experiment diagrams of setups all observations and comments required calculations with equations answers to the questions from the handouts the notebook must be legible and neatly done so somebody else reading your notebook could understand what you did. As a result of that, a change in the sample environment is observed as deflections of the fringes. This algorithm is based on a set of points linked together and with a behavior similar to a rubber band, in which these points are attracted to. The intensity oscillation depends only on the distance between the moving grating g 1 and the fixed grating g 2. The test involves creating a low frequency moire pattern between two periodic patterns which are rotated slightly with respect to one another.

Heterodyne moire is relatively inexpensive and has high variable sensitivity. Moire deflectometry produces result that appears similar to an interferometry technique. Stutman department of physics and astronomy, johns hopkins university, baltimore, md. Multiplication by two and three is illustrated in figs. Development and implementation of talbotlau xray deflectometry. Yag laser with a beam power of mw and was focused onto the sample by a lens with cm focal length, and the beam waist radius 0 was measured to be. Our study shows that, in order to avoid artifacts, the reference pattern must be exactly matched in phase with the object fringe. A propagator which expresses the change in mtf with the path is defined and demonstrated on a colloidal solution serving as the tested object. The problem that is addressed here is the measurement of the mechanical properties of very thin, transparent films using bulge tests. This is when a light beam passes through a plasma medium, which is between two gratings, and is then deflected due to the difference in refractive indices between the air and.

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