Moiré pattern

About: Moiré pattern is a research topic. Over the lifetime, 1917 publications have been published within this topic receiving 27176 citations. The topic is also known as: moiré fringes & moire pattern.

Estimation and Measurement of the Frequency of Coarse Gratings by Moire Fringe Techniques

Abstract: Moire fringes are obtained when two gratings of about same frequency are superposed on each other. Normally the two gratings are of special geometrical curves. For the present particular application, one grating is assumed to be a grating of constant but unknown frequency. The other grating which is the measuring grating consists of different types of curves. The theory of the resulting pattern and how it is used to measure the frequency is presented.

Investigation of Low Temperature Deformation Measurement Problem by the Contact Holographic Interferometers

Abstract: The materials currently used in modern structures do dramatically change their mechanical properties under the influence of low operating temperatures. One of the factors affecting the breakdown of various structural elements at low temperatures, is the placement of the stress concentrations. The existing analytical design schemes cannot always correctly take into account the material mechanical properties changes caused by the temperature decrease. In the present work we consider the method of contact holographic interferometry, which made it possible to efficiently determine surface displacements and strains at the temperature of –50 °C. The contact holographic interferometer is presented as an assembly of the object surface section and holographic plate in an immediate vicinity to the object. This technique is used to determine in-plane and out-of-plane displacements of tested object. If a hologram is recorded at metallized grating surface it restores information peculiar to some optical methods: holographic interferometry, speckle photography, holographic moire and mirror-optical method. For the interpretation of interference patterns new simple analytical equations are obtained. Contact holographic interferometers are used effectively to solve some elasto-plastic deformation measurement problems of isotropic and polycristalline materials. It is specially designed to permit the accurate measurement of the in-plane component of strain in the immediate vicinity of stress concentrators in plates.

Morphology Deformation and Giant Electronic Band Modulation in Long-Wavelength WS2 Moiré Superlattices.

Abstract: As a lattice interference effect, moiré superlattices feature a magnification effect that they respond sensitively to both the extrinsic mechanical perturbations and intrinsic atomic reconstructions. Here, using scanning tunneling microscopy and spectroscopy, we observe that long-wavelength WS2 superlattices are reconstructed into various moiré morphologies, ranging from regular hexagons to heavily deformed ones. We show that a dedicated interplay between the extrinsic nonuniform heterostrain and the intrinsic atomic reconstruction is responsible for this interesting moiré structure evolution. Importantly, the interplay between these two factors also introduces a local inhomogeneous intralayer strain within a moiré. Contrary to the commonly reported electronic modulation that occurred at the valence band edge due to interlayer hybridization, we find that this local intralayer strain induces a strong modulation at K point of the conduction band, reaching up to 300 meV in the heavily deformed moiré. Our microscopic explorations provide valuable information in understanding the intriguing physics in TMD moirés.

Pulse moire interferogram of rocket exhaust plume and its quantitative anaylsis

Abstract: This paper presented the measurement of the exhaust plume field of solid rocket with a moire interferometer. The principle of the moire interferometer is presented. The moire interferograms of the plume were processed with computer digital image process technique. It was found that the grey distribution of the moire interferograms has a sharp valley, and from the analysis this paper presented a method to thin and trace a deformated moire fringe on one step. This paper presented the result of the quantitative measurement.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The dot matrix hologram with hidden moire pattern

Abstract: The present invention relates to a dot matrix hologram with hidden moire pattern which applies the moire technology in the dot matrix hologram. The main body region of the moire pattern and the background region of the moire pattern are formed by interleaving the same bright and dark lines in the hidden moire pattern region of the dot matrix hologram, but there is a position shifting between the line patterns in these two regions, and the position shifting is several times larger than the grating dot. Therefore, the invisibility of the moire pattern in the hidden moire pattern region without special processing is not good, usually the moire pattern can directly be seen by eye without using the decoding film, so the effect in this kind of application of moire pattern is pretty bad. But the moire pattern of the present invention ingeniously uses the camouflage pattern to prevent the occurrence of the above mentioned phenomena, and also it can make this kind of the dot matrix hologram more nice-looking. Furthermore, the present invention extends the one-dimensional moire pattern technology to two-dimensional moire pattern technology, which not only increases the quantity of information hidden, but enhances the invisibility of moire pattern.