Journal articles: 'Effet moiré'

1

Yi, Xue Feng, and Si Chun Long. "Precision Displacement Measurement of Single Lens Reflex Digital Camera." Applied Mechanics and Materials 103 (September 2011): 82–86. http://dx.doi.org/10.4028/www.scientific.net/amm.103.82.

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When the stripes are photographed by digital cameras,Moiré fringes will be in the photograph. With the displacement amplification of Moiré fringes, tiny movement of stripes can be calculated precisely. We expounded its calculating methods in this paper. Experimental data show that high precision can be guaranteed.It is well known that the high rate zoom characteristic of moire fringe technique can be well used in precise measurement of digital Camera’s displacement, and besides, widely used in machining, laboratory and photo-electricity equipment. With the development and popularization of digital cameras, especially the great advancement in image sensor’s performance, it now becomes possible to accurately measure the displacement from far away by taking into account the sensor’s moire effect.

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Spillmann, Lothar. "The Perception of Movement and Depth in Moiré Patterns." Perception 22, no. 3 (March 1993): 287–308. http://dx.doi.org/10.1068/p220287.

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Moiré patterns can produce striking movement effects and in more complex stimuli can induce vivid stereoscopic depth. The physical rules underlying these phenomena are reviewed and their relationship to psychophysics is discussed. First, it is shown how moirés in ‘optical line interference’ patterns are created by superimposing periodic visual stimuli, eg gratings, and shifting them relative to each other. When two gratings are presented in this manner, small differences in spatial frequency, orientation, and speed are magnified. This magnification has prompted the use of moiré patterns both in industry and in art where their enhanced sensitivity to misalignment and spatial distortion has been widely exploited. Next, it is demonstrated how enhanced depth in ‘stereoscopic interference’ patterns is produced by presenting grating stimuli in two (or more) depth planes. The perceived depth effect in the resulting moiré pattern can be elicited similarly by binocular disparity and motion parallax. Finally, it is described how perceived movements occurring in different directions and at different depths are the basis for the perceptual ‘irritations’ that fascinate observers in complex moiré patterns. The use of moirés for the noninvasive examination of the human retina by aliasing is discussed.

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Fung, Kai-hung. "Creating Special Visual Effects with Moiré Patterns in Stereoscopic 3D and 4D Computed Tomographic Art." Leonardo 43, no. 3 (June 2010): 306–7. http://dx.doi.org/10.1162/leon.2010.43.3.306.

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Moiré pattern refers to an interference pattern that is observed when two sets of grid lines overlay one another. With special 3D rendering technique such as the “Rainbow Technique” for tomographic art generated from computed tomography (CT), the Moiré pattern can be utilized for its aesthetic effect, particularly in stereoscopic motion images to create a special visual effect. The use of the Moire pattern is featured in my piece Deep Within in the new media art exhibition “Digit@logue” curated by Ellen Pau held in Hong Kong Museum of Art in 2008.

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Gao, Yuan, Pengfei Li, Fan Gong, Sihong Zhai, Chaohao Wang, and Lei Zhao. "P‐3.5: Research on Reducing Moiré Patterns in Naked‐eye 3D Displays through Optimizing Lenticular Lens Tilt Angle." SID Symposium Digest of Technical Papers 55, S1 (April 2024): 729–33. http://dx.doi.org/10.1002/sdtp.17188.

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In the domain of Naked‐eye 3D display technology, the periodic interference between lenticular lens and screen subpixels frequently results in the generation of moiré patterns, which significantly impair image quality. This study proposes a strategy to reduce moir é artifacts by adjusting the tilt angle of the lenticular lens. Relying on the human eye sensitivity function, we have conducted a thorough analysis of the moiré patterns caused by the interference between the lenticular lens and the screen at various tilt angles. After extensive research, it has been discovered that the analytical method which applies spectral sensitivity weighting subsequent to the consideration of the human eye sensitivity function aligns more closely with the actual perception of moiré patterns by the human eye. This approach enables a more precise determination of the optimal tilt angles for lenticular lenses and screens, thereby substantially minimizing the moiré effect. The implications of this finding are significant for the realization of high‐quality, high‐definition naked‐eye 3D image displays, and may positively contribute to advancements within this technical field.

5

Yu, Hongyi, Mingxing Chen, and Wang Yao. "Giant magnetic field from moiré induced Berry phase in homobilayer semiconductors." National Science Review 7, no. 1 (August 13, 2019): 12–20. http://dx.doi.org/10.1093/nsr/nwz117.

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Abstract When quasiparticles move in condensed matters, the texture of their internal quantum structure as a function of position and momentum can give rise to Berry phases that have profound effects on the material’s properties. Seminal examples include the anomalous Hall and spin Hall effects from the momentum-space Berry phases in homogeneous crystals. Here, we explore a conjugate form of the electron Berry phase arising from the moiré pattern: the texture of atomic configurations in real space. In homobilayer transition metal dichalcogenides, we show that the real-space Berry phase from moiré patterns manifests as a periodic magnetic field with magnitudes of up to hundreds of Tesla. This quantity distinguishes moiré patterns from different origins, which can have an identical potential landscape, but opposite quantized magnetic flux per supercell. For low-energy carriers, the homobilayer moirés realize topological flux lattices for the quantum-spin Hall effect. An interlayer bias can continuously tune the spatial profile of the moiré magnetic field, whereas the flux per supercell is a topological quantity that can only have a quantized jump observable at a moderate bias. We also reveal the important role of the non-Abelian Berry phase in shaping the energy landscape in small moiré patterns. Our work points to new possibilities to access ultra-high magnetic fields that can be tailored to the nanoscale by electrical and mechanical controls.

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Yao, Li Li, Hai Bo Shi, Chang Liu, and Zhong Hua Han. "Solving the Two-Objective Shop Scheduling Problem in MTO Manufacturing Systems by a Novel Genetic Algorithm." Advanced Materials Research 314-316 (August 2011): 1315–20. http://dx.doi.org/10.4028/www.scientific.net/amr.314-316.1315.

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With the characteristics of un-touching, high-automatic and high-speed, we measured 3D shape by digital moiré patterns. And it can measure 3D shape without compensator, auxiliary mirror, hologram and other assistant modules. So it is widely used in measurement of 3D shape. But with the negative effect of grating area and CCD resolution of the camera, it has some problems in large aperture, steep aspheric surface, even off-axis aspheric testing. Focus on these problems; this paper established a sub-region splicing measurement of aspheric surface by using the combination of digital moire patterns and digital phase shifting technology. This paper also illustrated the basic theory, and the mathematical implementation procedure. In all, sub-region splicing digital moiré patterns can be considered as another method, which beyond compensation tests to measurement of aspheric surface.

7

Wang, Shaofeng, Jizhe Song, Mengtao Sun, and Shuo Cao. "Emerging Characteristics and Properties of Moiré Materials." Nanomaterials 13, no. 21 (October 30, 2023): 2881. http://dx.doi.org/10.3390/nano13212881.

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In recent years, scientists have conducted extensive research on Moiré materials and have discovered some compelling properties. The Moiré superlattice allows superconductivity through flat-band and strong correlation effects. The presence of flat bands causes the Moiré material to exhibit topological properties as well. Modulating electronic interactions with magnetic fields in Moiré materials enables the fractional quantum Hall effect. In addition, Moiré materials have ferromagnetic and antiferromagnetic properties. By tuning the interlayer coupling and spin interactions of the Moiré superlattice, different magnetic properties can be achieved. Finally, this review also discusses the applications of Moiré materials in the fields of photocurrent, superconductivity, and thermoelectricity. Overall, Moiré superlattices provide a new dimension in the development of two-dimensional materials.

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Yoshimura, Jun-ichi. "Theoretical study of the properties of X-ray diffraction moiré fringes. I." Acta Crystallographica Section A Foundations and Advances 71, no. 4 (May 14, 2015): 368–81. http://dx.doi.org/10.1107/s2053273315004970.

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A detailed and comprehensive theoretical description of X-ray diffraction moiré fringes for a bicrystal specimen is given on the basis of a calculation by plane-wave dynamical diffraction theory. Firstly, prior to discussing the main subject of the paper, a previous article [Yoshimura (1997).Acta Cryst.A53, 810–812] on the two-dimensionality of diffraction moiré patterns is restated on a thorough calculation of the moiré interference phase. Then, the properties of moiré fringes derived from the above theory are explained for the case of a plane-wave diffraction image, where the significant effect ofPendellösungintensity oscillation on the moiré pattern when the crystal is strained is described in detail with theoretically simulated moiré images. Although such plane-wave moiré images are not widely observed in a nearly pure form, knowledge of their properties is essential for the understanding of diffraction moiré fringes in general.

9

Li, Zhenyao, Jia-Min Lai, and Jun Zhang. "Review of phonons in moiré superlattices." Journal of Semiconductors 44, no. 1 (January 1, 2023): 011902. http://dx.doi.org/10.1088/1674-4926/44/1/011902.

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Abstract Moiré patterns in physics are interference fringes produced when a periodic template is stacked on another similar one with different displacement and twist angles. The phonon in two-dimensional (2D) material affected by moiré patterns in the lattice shows various novel physical phenomena, such as frequency shift, different linewidth, and mediation to the superconductivity. This review gives a brief overview of phonons in 2D moiré superlattice. First, we introduce the theory of the moiré phonon modes based on a continuum approach using the elastic theory and discuss the effect of the moiré pattern on phonons in 2D materials such as graphene and MoS2. Then, we discuss the electron–phonon coupling (EPC) modulated by moiré patterns, which can be detected by the spectroscopy methods. Furthermore, the phonon-mediated unconventional superconductivity in 2D moiré superlattice is introduced. The theory of phonon-mediated superconductivity in moiré superlattice sets up a general framework, which promises to predict the response of superconductivity to various perturbations, such as disorder, magnetic field, and electric displacement field.

10

Yoshimura, Jun-ichi. "Theoretical study of the properties of X-ray diffraction moiré fringes. II. Illustration of angularly integrated moiré images." Acta Crystallographica Section A Foundations and Advances 75, no. 4 (June 26, 2019): 610–23. http://dx.doi.org/10.1107/s2053273319004601.

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Using a theory of X-ray diffraction moiré fringes developed in a previous paper, labelled Part I [Yoshimura (2015). Acta Cryst. A71, 368–381], the X-ray moiré images of a silicon bicrystal having a weak curvature strain and an interspacing gap, assumed to be integrated for an incident-wave angular width, are simulation-computed over a wide range of crystal thicknesses and incident-wave angular width, likely under practical experimental conditions. Along with the simulated moiré images, the graphs of characteristic quantities on the moiré images are presented for a full understanding of them. The treated moiré images are all of rotation moiré. Mo Kα1 radiation and the 220 reflection were assumed in the simulation. The results of this simulation show that fringe patterns, which are significantly modified from simple straight fringes of rotation moiré, appear in some ranges of crystal thicknesses and incident-wave angular width, due to a combined effect of Pendellösung oscillation and an added phase difference from the interspacing gap, under the presence of a curvature strain. The moiré fringes which slope to the perpendicular direction to the diffraction vector in spite of the assumed condition of rotation moiré, and fringe patterns where low-contrast bands are produced with a sharp bend of fringes arising along the bands are examples of the modified fringe pattern. This simulation study provides a wide theoretical survey of the type of bicrystal moiré image produced under a particular condition.

11

Chen, Guang Xue, Qi Feng Chen, Jing Lei Tai, and Jiang Wen Liu. "Halftoning Method and Reproduction of Color Gamut in Digital Image Output." Applied Mechanics and Materials 421 (September 2013): 138–43. http://dx.doi.org/10.4028/www.scientific.net/amm.421.138.

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Image halftoning is the core technique of digital image output, which determines the quality of the color and tonal gradation reproduction. In this paper, the existing halftoning techniques were analyzed and evaluated, such as FM halftoning and AM halftoning, etc. And a new halftoning mode, frequency conversion amplitude modulation (FCAM), was proposed. This method is still based on AM halftoning, but it uses the different screen frequency for halftoning image of the different color version, so as to avoid moiré fringes on the smaller superposition angle. The use of new halftoning model can achieve halftoning image output which is more than 4 colors (such as 6 colors or 7 colors) without visual moirè pattern when overprinting. By the new technique, high-fidelity printing is achieved, and the color gamut of the output image is expanded, and we can get more vivid realistic effect of image transmission. We tested color gamut expansion of 6 colors and 7 colors high-fidelity printing, and obtained the expected conclusion by quantitative analysis.

12

Jadaun, Priyamvada, and Bart Soreé. "Review of Orbital Magnetism in Graphene-Based Moiré Materials." Magnetism 3, no. 3 (August 28, 2023): 245–58. http://dx.doi.org/10.3390/magnetism3030019.

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Recent years have seen the emergence of moiré materials as an attractive platform for observing a host of novel correlated and topological phenomena. Moiré heterostructures are generated when layers of van der Waals materials are stacked such that consecutive layers are slightly mismatched in their lattice orientation or unit cell size. This slight lattice mismatch gives rise to a long-wavelength moiré pattern that modulates the electronic structure and leads to novel physics. The moiré superlattice results in flat superlattice bands, electron–electron interactions and non-trivial topology that have led to the observation of superconductivity, the quantum anomalous Hall effect and orbital magnetization, among other interesting properties. This review focuses on the experimental observation and theoretical analysis of orbital magnetism in moiré materials. These systems are novel in their ability to host magnetism that is dominated by the orbital magnetic moment of Bloch electrons. This orbital magnetic moment is easily tunable using external electric fields and carrier concentration since it originates in the quantum anomalous Hall effect. As a result, the orbital magnetism found in moiré superlattices can be highly attractive for a wide array of applications including spintronics, ultra-low-power magnetic memories, spin-based neuromorphic computing and quantum information technology.

13

Arora, Arpit, and Justin C. W. Song. "A moiré proximity effect." Nature Materials 23, no. 2 (February 2024): 165–66. http://dx.doi.org/10.1038/s41563-023-01781-0.

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Huang, Xinyu, Xu Han, Yunyun Dai, Xiaolong Xu, Jiahao Yan, Mengting Huang, Pengfei Ding, et al. "Recent progress on fabrication and flat-band physics in 2D transition metal dichalcogenides moiré superlattices." Journal of Semiconductors 44, no. 1 (January 1, 2023): 011901. http://dx.doi.org/10.1088/1674-4926/44/1/011901.

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Abstract Moiré superlattices are formed when overlaying two materials with a slight mismatch in twist angle or lattice constant. They provide a novel platform for the study of strong electronic correlations and non-trivial band topology, where emergent phenomena such as correlated insulating states, unconventional superconductivity, and quantum anomalous Hall effect are discovered. In this review, we focus on the semiconducting transition metal dichalcogenides (TMDs) based moiré systems that host intriguing flat-band physics. We first review the exfoliation methods of two-dimensional materials and the fabrication technique of their moiré structures. Secondly, we overview the progress of the optically excited moiré excitons, which render the main discovery in the early experiments on TMD moiré systems. We then introduce the formation mechanism of flat bands and their potential in the quantum simulation of the Hubbard model with tunable doping, degeneracies, and correlation strength. Finally, we briefly discuss the challenges and future perspectives of this field.

15

Saveljev, Vladimir. "Moiré effect in cylindrical objects." Journal of the Korean Physical Society 68, no. 9 (May 2016): 1075–82. http://dx.doi.org/10.3938/jkps.68.1075.

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Garcia-Sucerquia, Jorge, Juan Carrasquilla, and Diego Hincapié. "Wavemeter based on moiré effect." Applied Optics 43, no. 33 (November 20, 2004): 6095. http://dx.doi.org/10.1364/ao.43.006095.

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Zhao, Xiao Mei, and Bing Xie. "Halftone Image Processing Method of Security Based on Moiré Effect." Applied Mechanics and Materials 200 (October 2012): 712–18. http://dx.doi.org/10.4028/www.scientific.net/amm.200.712.

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A halftone image processing method of security based on moiré effect is developed in this paper. On the theoretical basis of moiré effect and information hiding in halftone images, some images and text information are hidden in the pre-copy color images, and then the images are output by means of laser printers and traditional printing proof. The experimental results show that when the specific detecting film is in the right angle and position, the hidden graphic information can be clearly observed. This security method is of better effect, lower production costs, which can be widely used in packaging security printing.

18

Yu, Dajie, Junbo Liu, Ji Zhou, Haifeng Sun, Chuan Jin, and Jian Wang. "Depth–Depth of Focus Moiré Fringe Alignment via Broad-Spectrum Modulation." Photonics 11, no. 2 (January 31, 2024): 138. http://dx.doi.org/10.3390/photonics11020138.

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Alignment precision is a crucial factor that directly impacts overlay accuracy, which is one of three fundamental indicators of lithography. The alignment method based on the Moiré fringe has the advantages of a simple measurement optical path and high measurement accuracy. However, it requires strict control of the distance between the mask and wafer to ensure imaging quality. This limitation restricts its application scenarios. A depth–DOF (depth of focus) Moiré fringe alignment by broad–spectrum modulation is presented to enhance the range of the alignment signals. This method establishes a broad–spectrum Moiré fringe model based on the Talbot effect principle, and it effectively covers the width of dark field (WDF) between different wavelength imaging ranges, thereby extending the DOF range of the alignment process, and employs a hybrid of genetic algorithms and the particle-swarm optimization (GA–PSO) algorithm to combine various spectral components in a white spectrum. By calculating the optimal ratio of each wavelength and using white light incoherent illumination in combination with this ratio, it achieves the optimal DOF range of a broad–spectrum Moiré fringe imaging model. The simulation results demonstrate that the available DOF range of the alignment system has been expanded from 400 μm to 800 μm. Additionally, the alignment precision of the system was analyzed, under the same conditions, and the accuracy analysis of the noise resistance, translation amount, and tilt amount was conducted for the Moiré fringe and broad–spectrum Moiré fringe. Compared to a single wavelength, the alignment precision of the broad–spectrum Moiré fringe decreased by an average of 0.0495 nm, equivalent to a 1.5% reduction in the original alignment precision, when using a 4 μm mask and a 4.4 μm wafer. However, the alignment precision can still reach 3.795 nm, effectively enhancing the available depth of focus range and reducing the loss of alignment precision.

19

Xie, Hui Min, Satoshi Kishimoto, Yan Jie Li, Dao Zhi Liu, Ming Zhang, and Zhen Xing Hu. "Deformation Analysis of Shape Memory Alloy Using SEM Scanning Moiré Method." Advanced Materials Research 33-37 (March 2008): 675–80. http://dx.doi.org/10.4028/www.scientific.net/amr.33-37.675.

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In this paper, scanning electron moiré method is used to measure the mechanical behavior of Ferro-based shape memory alloys(SMA). The moiré patterns are formed by the interference between a 1000 lines/mm cross-type specimen grating (which is fabricated using electron beam lithography) and the scanning lines of Scanning Electron Microscope (SEM). When the specimen is subjected to uniform tension load at the room temperature, the unloading residual strain values in the different regions under the same tensile load and the values in the same region under different tensile loads are compared respectively. The shape memory effect is also studied. From the experimental results, it can be concluded that the proposed moiré method is highly accurate to measure the mechanical behavior of microscopic field.

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Chowdhury, Suman, Victor A. Demin, Leonid A. Chernozatonskii, and Alexander G. Kvashnin. "Ultra-Low Thermal Conductivity of Moiré Diamanes." Membranes 12, no. 10 (September 25, 2022): 925. http://dx.doi.org/10.3390/membranes12100925.

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Ultra-thin diamond membranes, diamanes, are one of the most intriguing quasi-2D films, combining unique mechanical, electronic and optical properties. At present, diamanes have been obtained from bi- or few-layer graphene in AA- and AB-stacking by full hydrogenation or fluorination. Here, we study the thermal conductivity of diamanes obtained from bi-layer graphene with twist angle θ between layers forming a Moiré pattern. The combination of DFT calculations and machine learning interatomic potentials makes it possible to perform calculations of the lattice thermal conductivity of such diamanes with twist angles θ of 13.2∘, 21.8∘ and 27.8∘ using the solution of the phonon Boltzmann transport equation. Obtained results show that Moiré diamanes exhibit a wide variety of thermal properties depending on the twist angle, namely a sharp decrease in thermal conductivity from high for “untwisted” diamanes to ultra-low values when the twist angle tends to 30∘, especially for hydrogenated Moiré diamanes. This effect is associated with high anharmonicity and scattering of phonons related to a strong symmetry breaking of the atomic structure of Moiré diamanes compared with untwisted ones.

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Zhang, Yang, Trithep Devakul, and Liang Fu. "Spin-textured Chern bands in AB-stacked transition metal dichalcogenide bilayers." Proceedings of the National Academy of Sciences 118, no. 36 (September 2, 2021): e2112673118. http://dx.doi.org/10.1073/pnas.2112673118.

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While transition-metal dichalcogenide (TMD)–based moiré materials have been shown to host various correlated electronic phenomena, topological states have not been experimentally observed until now [T. Li et al., Quantum anomalous Hall effect from intertwined moiré bands. arXiv [Preprint] (2021). https://arxiv.org/abs/2107.01796 (Accessed 5 July 2021)]. In this work, using first-principle calculations and continuum modeling, we reveal the displacement field–induced topological moiré bands in AB-stacked TMD heterobilayer MoTe2/WSe2. Valley-contrasting Chern bands with nontrivial spin texture are formed from interlayer hybridization between MoTe2 and WSe2 bands of nominally opposite spins. Our study establishes a recipe for creating topological bands in AB-stacked TMD bilayers in general, which provides a highly tunable platform for realizing quantum-spin Hall and interaction-induced quantum anomalous Hall effects.

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Hane, K., T. Goto, S. Watanabe, and S. Hattori. "Moiré signals by the photoacoustic effect." Optics Letters 15, no. 22 (November 15, 1990): 1318. http://dx.doi.org/10.1364/ol.15.001318.

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Saveljev, Vladimir, Sung-Kyu Kim, and Jaisoon Kim. "Moiré effect in displays: a tutorial." Optical Engineering 57, no. 03 (March 28, 2018): 1. http://dx.doi.org/10.1117/1.oe.57.3.030803.

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Bernero, Bruce. "The Moiré Effect in Physics Teaching." Physics Teacher 27, no. 8 (November 1989): 602–9. http://dx.doi.org/10.1119/1.2342888.

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Zhang, Shi-Hao, Bo Xie, Ran Peng, Xiao-Qian Liu, Xin Lu, and Jian-Peng Liu. "Novel electrical properties of moiré graphene systems." Acta Physica Sinica 72, no. 6 (2023): 1. http://dx.doi.org/10.7498/aps.72.20230120.

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In this review, we discuss the electronic structures, topological properties, correlated states, nonlinear optical responses, as well as phonon and electron-phonon coupling effects of moiré graphene superlattices. First, we illustrate that topologically non-trivial flat bands and moiré orbital magnetism are ubiquitous in various twisted graphene systems. In particular, the topological flat bands of magic-angle twisted bilayer graphene (TBG) can be explained from a zeroth pseudo-Landau-level picture, which can naturally explain the experimentally observed quantum anomalous Hall effect and some of the other correlated states. These topologically nontrivial flat bands may lead to nearly quantized piezoelectric response, which can be used to directly probe the valley Chern numbers in these moiré graphene systems. A simple and general chiral decomposition rule is reviewed and discussed, which can be used to predict the low-energy band dispersions of generic twisted mulilayer graphene system and alternating twisted multilayer graphene system. This review further discusses nontrivial interaction effects of magic-angle TBG such as the correlated insulator states, density wave states, cascade transitions, and nematic states, and proposes nonlinear optical measurement as an experimental probe to distinguish the different "featureless" correlated states.The phonon properties and electron-phonon coupling effects are also briefly reviewed. The novel physics emerging from band-aligned graphene-insulator heterostructres is also discussed in this review. In the end, we make a summary and an outlook about the novel physical properties of moiré superlattices, two-dimensional materials, moiré superlattices－ two dimensional materials.

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Han, Chien-Yuan, Wen-Tai Lo, Kun-Huang Chen, Ju-Yi Lee, Chien-Hung Yeh, and Jing-Heng Chen. "Measurement of Focal Length and Radius of Curvature for Spherical Lenses and Mirrors by Using Digital-Grating Moiré Effect." Photonics 8, no. 7 (July 1, 2021): 252. http://dx.doi.org/10.3390/photonics8070252.

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This paper proposes the use of digital-grating moiré effect for measuring the focal lengths and radius of curvatures of biconvex and biconcave spherical simple lenses and spherical mirrors. Based on Fresnel diffraction, the equation for the electric field of propagated light passing through the test samples was derived. Through digital image post processing, the recorded intensity on an observation screen was superimposed on a digital grating to generate a moiré pattern. On substituting the slant angle of the moiré pattern into the derived equation, the focal lengths and radius of curvatures could be determined. The experimental results successfully demonstrated the feasibility of the proposed method; the percent errors for focal length and radius of curvature measurement were less than 0.5%. The measurement uncertainty was analyzed and the correctness of the derived equation was confirmed through simulation. Because of the use of digital image post processing, the proposed method has advantages such as a simple set up, easy operation, high stability, high accuracy, and low cost. Thus, the method has considerable potential in relevant application.

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Liao, Yan Ling, and Xin Guang Lv. "Effect of Screen Angle on Moire in Printing." Applied Mechanics and Materials 469 (November 2013): 326–30. http://dx.doi.org/10.4028/www.scientific.net/amm.469.326.

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Moire, an abnormal printing pattern formed by irregular screen tone, may adversely affect the printing quality and should be avoided during printing. Hence, it is necessary to understand the factors contributing to its formation. Being one of the most important factors, the effect of screen angle is discussed in this paper. To obtain the most suitable screen angle and confirm its rationality, Photoshop is used to simulate Moire patterns under different screen angle conditions and analyze the relationship between screen angles and formation of Moire pattern. When mixing two of Cyan, Magenta, Yellow, and Black colors randomly while keeping the others constant, the size of the Moire is not affected by screen angles but by the angle differences. When the difference is at 28° and 38°, Moire pattern is not obvious and the dots are evenly distributed. The screen angle difference and the screen angle of the key color are also analyzed from the Moire pattern obtained by varying screen angle between C, M, and K (Black) in the simulation study. The results show that it is reasonable to set screen angle for strong color at 15°, 45° and 75°.

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Ge, Jing Huan, Jie Pan, and Meng Xiao Li. "Anti-Counterfeiting Technologies for Digital Halftone Images Based on Moire Methods." Advanced Materials Research 989-994 (July 2014): 3571–74. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.3571.

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Moire effect is a special optical phenomenon caused by the interference of light. In the printing industry, it is also called Moire phenomenon which is caused by superposition of the multicolor printing dots for halftone images. Now it is widely used in the anti-counterfeiting areas. In this paper, we firstly introduce the basic principle of Moire effect. Then we describe several main applications of the Moire effect in the field of halftone image security. We review the main types of Moire-based anti-counterfeiting methods, compare them, and explain how they can be used for such security applications. It will provide the necessary technical information for the persons that in anti-counterfeiting area.

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Miao, Wenjing, Hao Sheng, and Jingang Wang. "Vertical Stress Induced Anomalous Spectral Shift of 13.17° Moiré Superlattice in Twist Bilayer Graphene." Molecules 28, no. 7 (March 28, 2023): 3015. http://dx.doi.org/10.3390/molecules28073015.

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The electronic states of the twist bilayer graphene (TBG) moiré superlattice are usually regulated by the rotation angle, applied electric field, applied magnetic field, carrier concentration and applied stress, and thus exhibit novel physical properties. Squeezing, that is, applying vertical compressive stress to the graphene layers, has profound significance in regulating the photoelectric properties of the moiré superlattice and constructing optical nanodevices. This paper presents the photoelectric properties of a TBG moiré superlattice with a twist angle of 13.17° and tunability under vertical stress. Interlayer distance decreases nonlinearly with compressive stress from 0 to 10 GPa, giving rise to weakened interlayer coupling compared to a Bernal-stacked graphene bilayer and an enhanced repulsive effect between the layers. The calculated Bloch wave functions show a strong dependence on stress. With the increase in stress, the band gaps of the system present a nonlinear increase, which induces and enhances the interlayer charge transfer and leads to the redshift of the absorption spectrum of the moiré superlattice system. By analyzing the differences in the Bloch wave function and charge density differences, we explain the nature of the physical mechanism of photoelectric property change in a stress-regulated twist superlattice system. This study provides a theoretical basis for the identification of piezoelectric properties and the stress regulation of photoelectric devices based on TBG, and also provides a feasible method for regulating the performance of TBG.

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Goyal, D., and A. H. King. "Simulation and Contrast Analysis of tem Images of Cracks." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 578–79. http://dx.doi.org/10.1017/s0424820100181658.

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TEM images of cracks have been found to give rise to a moiré fringe type of contrast. It is apparent that the moire fringe contrast is observed because of the presence of a fault in a perfect crystal, and is characteristic of the fault geometry and the diffracting conditions in the TEM. Various studies have reported that the moire fringe contrast observed due to the presence of a crack in an otherwise perfect crystal is distinctive of the mode of crack. This paper describes a technique to study the geometry and mode of the cracks by comparing the images they produce in the TEM because of the effect that their displacement fields have on the diffraction of electrons by the crystal (containing a crack) with the corresponding theoretical images. In order to formulate a means of matching experimental images with theoretical ones, displacement fields of dislocations present (if any) in the vicinity of the crack are not considered, only the effect of the displacement field of the crack is considered.The theoretical images are obtained using a computer program based on the two beam approximation of the dynamical theory of diffraction contrast for an imperfect crystal. The procedures for the determination of the various parameters involved in these computations have been well documented. There are three basic modes of crack. Preliminary studies were carried out considering the simplest form of crack geometries, i. e., mode I, II, III and the mixed modes, with orthogonal crack geometries. It was found that the contrast obtained from each mode is very distinct. The effect of variation of operating conditions such as diffracting vector (), the deviation parameter (ω), the electron beam direction () and the displacement vector were studied. It has been found that any small change in the above parameters can result in a drastic change in the contrast. The most important parameter for the matching of the theoretical and the experimental images was found to be the determination of the geometry of the crack under consideration. In order to be able to simulate the crack image shown in Figure 1, the crack geometry was modified from a orthogonal geometry to one with a crack tip inclined to the original crack front. The variation in the crack tip direction resulted in the variation of the displacement vector also. Figure 1 is a cross-sectional micrograph of a silicon wafer with a chromium film on top, showing a crack in the silicon.

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Gou, Jian, Longjuan Kong, Xiaoyue He, Yu Li Huang, Jiatao Sun, Sheng Meng, Kehui Wu, Lan Chen, and Andrew Thye Shen Wee. "The effect of moiré superstructures on topological edge states in twisted bismuthene homojunctions." Science Advances 6, no. 23 (June 2020): eaba2773. http://dx.doi.org/10.1126/sciadv.aba2773.

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Creating and controlling the topological properties of two-dimensional topological insulators is essential for spintronic device applications. Here, we report the successful growth of bismuth homostructure consisting of monolayer bismuthene and single-layer black phosphorus–like Bi (BP-Bi) on the HOPG surface. Combining scanning tunneling microscopy/spectroscopy with noncontact atomic force microscopy, moiré superstructures with twist angles in the bismuth homostructure and the modulation of topological edge states of bismuthene were observed and studied. First-principles calculations reproduced the moiré superlattice and indicated that the structure fluctuation is ascribed to the stacking modes between bismuthene and BP-Bi, which induce spatially distributed interface interactions in the bismuth homostructure. The modulation of topological edge states is directly related to the variation of interlayer interactions. Our results suggest a promising pathway to tailor the topological states through interfacial interactions.

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Saveljev, Vladimir, Woojun Han, Hakcheol Lee, Jaewan Kim, and Jaisoon Kim. "Moiré effect in double-layered coaxial cylinders." Applied Optics 59, no. 18 (June 17, 2020): 5596. http://dx.doi.org/10.1364/ao.392223.

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Wu, Sanfeng, Lei Wang, You Lai, Wen-Yu Shan, Grant Aivazian, Xian Zhang, Takashi Taniguchi, et al. "Multiple hot-carrier collection in photo-excited graphene Moiré superlattices." Science Advances 2, no. 5 (May 2016): e1600002. http://dx.doi.org/10.1126/sciadv.1600002.

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In conventional light-harvesting devices, the absorption of a single photon only excites one electron, which sets the standard limit of power-conversion efficiency, such as the Shockley-Queisser limit. In principle, generating and harnessing multiple carriers per absorbed photon can improve efficiency and possibly overcome this limit. We report the observation of multiple hot-carrier collection in graphene/boron-nitride Moiré superlattice structures. A record-high zero-bias photoresponsivity of 0.3 A/W (equivalently, an external quantum efficiency exceeding 50%) is achieved using graphene’s photo-Nernst effect, which demonstrates a collection of at least five carriers per absorbed photon. We reveal that this effect arises from the enhanced Nernst coefficient through Lifshtiz transition at low-energy Van Hove singularities, which is an emergent phenomenon due to the formation of Moiré minibands. Our observation points to a new means for extremely efficient and flexible optoelectronics based on van der Waals heterostructures.

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Wang, L. L., and D. Z. Yun. "Application of moiré shearing interferometry to slope measurement of shallow shells." Journal of Strain Analysis for Engineering Design 27, no. 1 (January 1, 1992): 45–48. http://dx.doi.org/10.1243/03093247v271045.

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A moiré shearing interferometry, used to analyse the interference effect in a particular optical set-up by the Fourier series method, is proposed in this paper. The slope fringe patterns of different shallow shells with eccentric holes are also given by this method.

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Li, Tingxin, Shengwei Jiang, Bowen Shen, Yang Zhang, Lizhong Li, Zui Tao, Trithep Devakul, et al. "Quantum anomalous Hall effect from intertwined moiré bands." Nature 600, no. 7890 (December 22, 2021): 641–46. http://dx.doi.org/10.1038/s41586-021-04171-1.

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Liu, Liren, Xiaoben Liu, and Liangang Ye. "Joint Talbot effect and logic-operated moiré patterns." Journal of the Optical Society of America A 7, no. 6 (June 1, 1990): 970. http://dx.doi.org/10.1364/josaa.7.000970.

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Dorrío, B. V., A. F. Doval, C. López, R. Soto, J. Blanco-García, J. L. Fernández, and M. Pérez-Amor. "Fizeau phase-measuring interferometry using the moiré effect." Applied Optics 34, no. 19 (July 1, 1995): 3639. http://dx.doi.org/10.1364/ao.34.003639.

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Saveljev, Vladimir, and Sung-Kyu Kim. "Theoretical estimation of moiré effect using spectral trajectories." Optics Express 21, no. 2 (January 16, 2013): 1693. http://dx.doi.org/10.1364/oe.21.001693.

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Lohmann, Adolf W., and Stefan Sinzinger. "Moiré effect as a tool for image processing." Journal of the Optical Society of America A 10, no. 1 (January 1, 1993): 65. http://dx.doi.org/10.1364/josaa.10.000065.

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Ji, Qing-Xin, Peng Liu, Warren Jin, Joel Guo, Lue Wu, Zhiquan Yuan, Jonathan Peters, et al. "Multimodality integrated microresonators using the Moiré speedup effect." Science 383, no. 6687 (March 8, 2024): 1080–83. http://dx.doi.org/10.1126/science.adk9429.

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High- Q microresonators are indispensable components of photonic integrated circuits and offer several useful operational modes. However, these modes cannot be reconfigured after fabrication because they are fixed by the resonator’s physical geometry. In this work, we propose a Moiré speedup dispersion tuning method that enables a microresonator device to operate in any of three modes. Electrical tuning of Vernier coupled rings switches operating modality to Brillouin laser, bright microcomb, and dark microcomb operation on demand using the same hybrid-integrated device. Brillouin phase matching and microcomb operation across the telecom C-band is demonstrated. Likewise, by using a single-pump wavelength, the operating mode can be switched. As a result, one universal design can be applied across a range of applications. The device brings flexible mixed-mode operation to integrated photonic circuits.

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Zhao, Siwen, Gonglei Shao, Zheng Vitto Han, Song Liu, and Tongyao Zhang. "Gate tunable spatial accumulation of valley-spin in chemical vapor deposition grown 40°-twisted bilayer WS₂." Journal of Semiconductors 44, no. 1 (January 1, 2023): 012001. http://dx.doi.org/10.1088/1674-4926/44/1/012001.

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Abstract The emerging two-dimensional materials, particularly transition metal dichalcogenides (TMDs), are known to exhibit valley degree of freedom with long valley lifetime, which hold great promises in the implementation of valleytronic devices. Especially, light–valley interactions have attracted attentions in these systems, as the electrical generation of valley magnetization can be readily achieved — a rather different route toward magnetoelectric (ME) effect as compared to that from conventional electron spins. However, so far, the moiré patterns constructed with twisted bilayer TMDs remain largely unexplored in regard of their valley spin polarizations, even though the symmetry might be distinct from the AB stacked bilayer TMDs. Here, we study the valley Hall effect (VHE) in 40°-twisted chemical vapor deposition (CVD) grown WS2 moiré transistors, using optical Kerr rotation measurements at 20 K. We observe a clear gate tunable spatial distribution of the valley carrier imbalance induced by the VHE when a current is exerted in the system.

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Lin, Jiang-Xiazi, Ya-Hui Zhang, Erin Morissette, Zhi Wang, Song Liu, Daniel Rhodes, K. Watanabe, T. Taniguchi, James Hone, and J. I. A. Li. "Spin-orbit–driven ferromagnetism at half moiré filling in magic-angle twisted bilayer graphene." Science 375, no. 6579 (January 28, 2022): 437–41. http://dx.doi.org/10.1126/science.abh2889.

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Strong electron correlation and spin-orbit coupling (SOC) can have a profound influence on the electronic properties of materials. We examined their combined influence on a two-dimensional electronic system at the atomic interface between magic-angle twisted bilayer graphene and a tungsten diselenide crystal. We found that strong electron correlation within the moiré flatband stabilizes correlated insulating states at both quarter and half filling, and that SOC transforms these Mott-like insulators into ferromagnets, as evidenced by a robust anomalous Hall effect with hysteretic switching behavior. The coupling between spin and valley degrees of freedom could be demonstrated through control of the magnetic order with an in-plane magnetic field or a perpendicular electric field. Our findings establish an experimental knob to engineer topological properties of moiré bands in twisted bilayer graphene and related systems.

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Bocarsly, Matan, Matan Uzan, Indranil Roy, Sameer Grover, Jiewen Xiao, Zhiyu Dong, Mikhail Labendik, et al. "De Haas–van Alphen spectroscopy and magnetic breakdown in moiré graphene." Science 383, no. 6678 (January 5, 2024): 42–48. http://dx.doi.org/10.1126/science.adh3499.

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Quantum oscillations originating from the quantization of electron cyclotron orbits provide sensitive diagnostics of electron bands and interactions. We report on nanoscale imaging of the thermodynamic magnetization oscillations caused by the de Haas–van Alphen effect in moiré graphene. Scanning by means of superconducting quantum interference device (SQUID)–on-tip in Bernal bilayer graphene crystal axis-aligned to hexagonal boron nitride reveals large magnetization oscillations with amplitudes reaching 500 Bohr magneton per electron in weak magnetic fields, unexpectedly low frequencies, and high sensitivity to superlattice filling fraction. The oscillations allow us to reconstruct the complex band structure, revealing narrow moiré bands with multiple overlapping Fermi surfaces separated by unusually small momentum gaps. We identified sets of oscillations that violate the textbook Onsager Fermi surface sum rule, signaling formation of broad-band particle-hole superposition states induced by coherent magnetic breakdown.

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Xing, Yong Ming, and Satoshi Kishimoto. "Fabrication of Superfine Electron Moiré Grid." Key Engineering Materials 326-328 (December 2006): 111–14. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.111.

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The electron moiré method uses a high frequency grating to measure microscopic deformation. Finer and finer gratings are being pursued to meet higher and higher resolution requirements in microscopic stress analysis. In this study, the techniques of fabricating electron grid by means of a scanning electron microscope are improved. The use of a low accelerating voltage shows a better effect than the high accelerating voltage in fabricating a superfine grid. A new group of parameters is suggested based on this consideration. A cross-line grid with a frequency of 10,000 lines/mm and a parallel grating with a frequency of 13,000 lines /mm have been successfully fabricated.

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Moutinho, Marcus V. O., Pedro Venezuela, and Marcos A. Pimenta. "Raman Spectroscopy of Twisted Bilayer Graphene." C 7, no. 1 (January 26, 2021): 10. http://dx.doi.org/10.3390/c7010010.

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When two periodic two-dimensional structures are superposed, any mismatch rotation angle between the layers generates a Moiré pattern superlattice, whose size depends on the twisting angle θ. If the layers are composed by different materials, this effect is also dependent on the lattice parameters of each layer. Moiré superlattices are commonly observed in bilayer graphene, where the mismatch angle between layers can be produced by growing twisted bilayer graphene (TBG) samples by CVD or folding the monolayer back upon itself. In TBG, it was shown that the coupling between the Dirac cones of the two layers gives rise to van Hove singularities (vHs) in the density of electronic states, whose energies vary with θ. The understanding of the behavior of electrons and their interactions with phonons in atomically thin heterostructures is crucial for the engineering of novel 2D devices. Raman spectroscopy has been often used to characterize twisted bilayer graphene and graphene heterostructures. Here, we review the main important effects in the Raman spectra of TBG discussing firstly the appearance of new peaks in the spectra associated with phonons with wavevectors within the interior of the Brillouin zone of graphene corresponding to the reciprocal unit vectors of the Moiré superlattice, and that are folded to the center of the reduced Brillouin Zone (BZ) becoming Raman active. Another important effect is the giant enhancement of G band intensity of TBG that occurs only in a narrow range of laser excitation energies and for a given twisting angle. Results show that the vHs in the density of states is not only related to the folding of the commensurate BZ, but mainly associated with the Moiré pattern that does not necessarily have a translational symmetry. Finally, we show that there are two different resonance mechanisms that activate the appearance of the extra peaks: the intralayer and interlayer electron–phonon processes, involving electrons of the same layer or from different layers, respectively. Both effects are observed for twisted bilayer graphene, but Raman spectroscopy can also be used to probe the intralayer process in any kind of graphene-based heterostructure, like in the graphene/h-BN junctions.

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Zhu, Rui, and Wen Hua Zheng. "Tilt Measurement Research Based on Moirefringetechnique of SLR Digital Camera." Applied Mechanics and Materials 90-93 (September 2011): 2840–43. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.2840.

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This paper analyzes the reason and condition of the generation of moire effect when taking photos with a digital camera, further studies a new tilt measurement method based on moire effects of SLR digital camera and then develops the general application of moirefringetechnique.

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Saveljev, Vladimir, Hakcheol Lee, and Jaisoon Kim. "Physical model of the moiré effect in cylindrical structures." Journal of the Korean Physical Society 71, no. 12 (July 24, 2017): 934–45. http://dx.doi.org/10.3938/jkps.71.934.

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Ai Yongxu, 艾永旭, 周翔 Zhou Xiang, 杜虎兵 Du Hubing, 郭家玉 Guo Jiayu, 杨涛 Yang Tao, and 赵磊 Zhao Lei. "Shadow Moiré Using Talbot Effect Under Point Light Illumination." Acta Optica Sinica 36, no. 4 (2016): 0412003. http://dx.doi.org/10.3788/aos201636.0412003.

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Serlin, M., C. L. Tschirhart, H. Polshyn, Y. Zhang, J. Zhu, K. Watanabe, T. Taniguchi, L. Balents, and A. F. Young. "Intrinsic quantized anomalous Hall effect in a moiré heterostructure." Science 367, no. 6480 (December 19, 2019): 900–903. http://dx.doi.org/10.1126/science.aay5533.

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The quantum anomalous Hall (QAH) effect combines topology and magnetism to produce precisely quantized Hall resistance at zero magnetic field. We report the observation of a QAH effect in twisted bilayer graphene aligned to hexagonal boron nitride. The effect is driven by intrinsic strong interactions, which polarize the electrons into a single spin- and valley-resolved moiré miniband with Chern number C = 1. In contrast to magnetically doped systems, the measured transport energy gap is larger than the Curie temperature for magnetic ordering, and quantization to within 0.1% of the von Klitzing constant persists to temperatures of several kelvin at zero magnetic field. Electrical currents as small as 1 nanoampere controllably switch the magnetic order between states of opposite polarization, forming an electrically rewritable magnetic memory.

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Jaworski, Adam. "Epilogue: the moiré effect and the art of assemblage." Social Semiotics 27, no. 4 (June 25, 2017): 532–43. http://dx.doi.org/10.1080/10350330.2017.1334405.

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Journal articles on the topic 'Effet moiré'

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