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.

Metal contacts with Moire interfaces on WSe2 for ambipolar applications

Abstract: The rational design of metal contacts on transition metal dichalcogenides can significantly improve the performance of 2D devices. We have previously shown that a Moire interface between n-type monolayer MoS2 and metal contacts enhances the stability of physisorptive interface sites, thereby enabling weaker Fermi level pinning and allowing easier variation of the Schottky barrier height at these interfaces. We extend these calculations to p-type and ambipolar WSe2 contacts in this work. The analysis shows that the Moire interfaces again have a weaker Fermi level pinning, while most metals have chemisorptive sites with stronger pinning. We find that the most stable site of Pd is a Moire site with an unusually low p-type Schottky barrier height (p-SBH), while Au has a metastable low p-SBH. In and Al retain their low n-type SBHs, which together with Pd enable ambipolar contacts by the choice of contact metals, indicating that WSe2 can be used for high-performance ambipolar devices with the rational design of contact metals.

3D measurement of human plantar foot by projection moiré technique

Abstract: An optical system composed of an LCD projector, a digital camera and a microcomputer aims to measure three-dimensionally human foot model and is based on projection moire technique. Four digital phase shifted parallel grating patterns are projected upon the specimen surface and observed by the camera. A phase map of moire fringes is produce digitally combining the fringe maps distorted by the foot whit those, left undistorted, by a reference plane. The 3D profile was calculated using two-dimensional greyscale images by dedicated software. This profile was compared to the measurement data of the same foot obtained from a coordinate measuring machine (CMM). A brief metrological analysis estimated an uncertainty value of 6.3% for the foot. The main advantages of this system were its easy set-up, use of standard optical components, absence of moving parts and its possible applicability in bioengineering.

Measuring device of dynamic displacement pattern by moire method

Abstract: PURPOSE:To enable indication of the displacement mode at each moment by setting up a standard grid movably and observing a momentary Moire interference fringes at a known slight displacement time continuously and recording in an image memory and thus by deciding the absolute order of interference based on a group of data of interference fringes consisting of each two values obtained by five segments CONSTITUTION:A three-dimensional surface condition at a standard time t1 is recorded as an image of a Moire interference fringe under a condition of the location of the first standard grid z=0 A surface condition at time (t1+DELTAt1) which can be considered as nearly the same as a surface condition at time t1 is recorded as an image of the secondary Moire interference fringe under a condition of the location of the standard grid z=+delta Bright Moire fringes are formed at the locations indicated by a set of blackround mark and white round mark approaching each other By selecting an amount of shift delta of the standard grid, a correspondence between a black round mark and a white round mark at the same fringe order before and after shifting the standard grid on an arbitrary cross-section, eg X-X axis is practiced by a simple calculation of comparison and also the shifting direction of the fringe of the same order cam be judged at the same time

Measurement of torsion angular distortion based on Moiré fringe

Abstract: A high-precision optical angular measurement method is proposed to measure the torsion angle based on the Moire fringe produced by double diffraction grating interference.In order to validate the validity of measurement equipment by Moire fringe,the schematic design and experimental analysis are carried out.The torsional flexibility of a three-dimensional object is simulated by collimator simulation equipment adjusted by a fine-tuning mechanical structure.The measurement experiments are carried out on the independent foundation platform.By comparing different design proposals with experiments,a scheme of CCD target surface installed in the image surface of parallel light is selected to use in this measurement.In this scheme,the image processing technology of filtering thinning is used to obtain the stripe width by treating the collected Moire fringe,and the torsional flexibility value is calculated by the mathematical model and the changes of stripes width.The experimental results show that the clearer Moire fringe image can be gotten in the scheme when the collimator is circumgyrated by fine-tuning institution in the field of view of ±7′.And the measuring accuracy of torsion angle is 4.3″(3σ) by the algorithms process when the Moire fringe width is 1 615~1 712 μm.This method meets the measurement requirements of high-accuracy of torsion angle between equipments,and it lays the foundation to enhance the photoelectric precision of measurement equipment.

Applications of x-ray interferometer-generated Moiré patterns

Abstract: A monolithic x-ray interferometer has been developed which provides a means of producing high-quality x-ray Moire fringes with readily controlled pitch (spacing). It was designed as a calibrator of sub-microradian angular displacements and it has successfully demonstrated the feasibility of the approach. The quality of its output, when combined with the phase imaging capabilities of interferometry and the latest generation of fringe analysis algorithms, suggests additional, novel applications. This paper first reviews the principles and performance of the system as an angular calibrator and then discusses the potential of x-ray Moire patterns in the form of an x-ray microscope and as a diagnostic tool for ultra-precision metrology. Demonstration results are given mostly in the form of images of fringe fields, since the point here is the production of original data suitable for processing by existing techniques.