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https://www.readbyqxmd.com/read/27906380/efficient-texture-mapping-by-adaptive-mesh-division-in-mesh-based-computer-generated-hologram
#1
Yeong-Min Ji, Hanju- Yeom, Jae-Hyeung Park
We propose a method that achieves efficient texture mapping in fully-analytic computer generated holograms based on triangular meshes. In computer graphics, the texture mapping is commonly used to represent the details of objects without increasing the number of the triangular meshes. In fully-analytic triangular-mesh-based computer generated holograms, however, those methods cannot be directly applied because each mesh cannot have arbitrary amplitude distribution inside the triangular mesh area in order to keep the analytic representation...
November 28, 2016: Optics Express
https://www.readbyqxmd.com/read/27906352/tunable-pancharatnam-berry-metasurface-for-dynamical-and-high-efficiency-anomalous-reflection
#2
He-Xiu Xu, Guang-Ming Wang, Tong Cai, Jun Xiao, Ya-Qiang Zhuang
Pancharatnam-Berry (PB) metasurfaces have intrigued a great deal of interest in recent years for anomalous reflection/refraction, vortex plate, orbital angular momentum, flat lens, photonic spin hall effect (PSHE), holograms and reflect/transmit arrays. However, almost all designs are restricted to fixed electrical performance/functionality once the design is finished. Here, we report for the first time a strategy for PB metasurface with agile working frequency by involving each meta-atom with tunable PIN diodes...
November 28, 2016: Optics Express
https://www.readbyqxmd.com/read/27906343/single-distance-phase-retrieval-algorithm-for-bragg-magnifier-microscope
#3
Stanislav Hrivňak, Jozef Uličný, Ladislav Mikeš, Angelica Cecilia, Elias Hamann, Tilo Baumbach, Libor Švéda, Zdenko Zápražný, Dušan Korytár, Eva Gimenez-Navarro, Ulrich H Wagner, Christoph Rau, Hartmut Greven, Patrik Vagovič
We present an improved, single-distance phase retrieval algorithm applicable for holographic X-ray imaging of biological objects for an in-line germanium Bragg Magnifier Microscope (BMM). The proposed algorithm takes advantage of a modified shrink-wrap algorithm for phase objects, robust unwrapping algorithm as well as other reasonable constraints applied to the wavefield at the object and the detector plane. The performance of the algorithm is analyzed on phantom objects and the results are shown and discussed...
November 28, 2016: Optics Express
https://www.readbyqxmd.com/read/27906211/simultaneous-generation-of-multiple-perfect-polarization-vortices-with-selective-spatial-states-in-various-diffraction-orders
#4
Shiyao Fu, Chunqing Gao, Tonglu Wang, Shikun Zhang, Yanwang Zhai
We demonstrate an approach to generate multiple perfect polarization vortices (PPVs) with selective spatial polarization distribution in various diffraction orders. The key is the design of a hologram with an anisotropic polarization diffraction grating. In the experiment, a setup consisting of two spatial light modulators is built. By encoding the specially designed holograms, PPVs with various states are obtained in different diffraction orders simultaneously, for instance, in radial and azimuthal polarized states...
December 1, 2016: Optics Letters
https://www.readbyqxmd.com/read/27905111/depth-enhancement-of-3d-microscopic-living-cell-image-using-incoherent-fluorescent-digital-holography
#5
L T Bang, H Y Wu, Y Zhao, E G Kim, N Kim
Multilayer images of living cells are typically obtained using confocal or multiphoton microscopy. However, limitations on the distance between consecutive scan layers hinder high-resolution three-dimensional reconstruction, and scattering strongly degrades images of living cell components. Consequently, when overlapping information from different layers is focused on a specific point in the camera, this causes uncertainty in the depiction of the cell components. We propose a method that combines the Fresnel incoherent correlation holography and a depth-of-focus reduction algorithm to enhance the depth information of three-dimensional cell images...
December 1, 2016: Journal of Microscopy
https://www.readbyqxmd.com/read/27901048/sparsity-based-multi-height-phase-recovery-in-holographic-microscopy
#6
Yair Rivenson, Yichen Wu, Hongda Wang, Yibo Zhang, Alborz Feizi, Aydogan Ozcan
High-resolution imaging of densely connected samples such as pathology slides using digital in-line holographic microscopy requires the acquisition of several holograms, e.g., at >6-8 different sample-to-sensor distances, to achieve robust phase recovery and coherent imaging of specimen. Reducing the number of these holographic measurements would normally result in reconstruction artifacts and loss of image quality, which would be detrimental especially for biomedical and diagnostics-related applications...
November 30, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27869850/effects-of-particle-locations-on-reconstructed-particle-images-in-digital-holography
#7
Christina Hesseling, Tim Homeyer, Joachim Peinke, Gerd Gülker
The intensity and phase reconstructed from digital in-line holograms by the convolution approach are analyzed. Distortions of particle images depending on their position in the plane transverse to the optical axis are identified. For this purpose, the object fields of numerically simulated particle holograms as well as of experimental data are reconstructed. The results of three-dimensional correlations of numerical and experimental data are superior when the numerically generated reference volumes are adapted to the transverse locations of the particle...
November 20, 2016: Applied Optics
https://www.readbyqxmd.com/read/27857428/holographic-tracking-and-sizing-of-optically-trapped-microprobes-in-diamond-anvil-cells
#8
F Saglimbeni, S Bianchi, G Gibson, R Bowman, M Padgett, R Di Leonardo
We demonstrate that Digital Holographic Microscopy can be used for accurate 3D tracking and sizing of a colloidal probe trapped in a diamond anvil cell (DAC). Polystyrene beads were optically trapped in water up to Gigapascal pressures while simultaneously recording in-line holograms at 1 KHz frame rate. Using Lorenz-Mie scattering theory to fit interference patterns, we detected a 10% shrinking in the bead's radius due to the high applied pressure. Accurate bead sizing is crucial for obtaining reliable viscosity measurements and provides a convenient optical tool for the determination of the bulk modulus of probe material...
November 14, 2016: Optics Express
https://www.readbyqxmd.com/read/27857318/improved-look-up-table-method-of-computer-generated-holograms
#9
Hui Wei, Guanghong Gong, Ni Li
Heavy computation load and vast memory requirements are major bottlenecks of computer-generated holograms (CGHs), which are promising and challenging in three-dimensional displays. To solve these problems, an improved look-up table (LUT) method suitable for arbitrarily sampled object points is proposed and implemented on a graphics processing unit (GPU) whose reconstructed object quality is consistent with that of the coherent ray-trace (CRT) method. The concept of distance factor is defined, and the distance factors are pre-computed off-line and stored in a look-up table...
November 10, 2016: Applied Optics
https://www.readbyqxmd.com/read/27857317/effective-information-processing-method-to-produce-a-computer-generated-hologram-based-on-a-spatial-light-modulator
#10
Su-Juan Liu, Di Wang, Song-Jie Li, Qiong-Hua Wang
In this paper, we propose an effective information processing method to produce a computer-generated hologram (CGH) based on a spatial light modulator (SLM). The method generates CGHs according to the property of the field of view (FOV), which, to the best of our knowledge, has never been proposed before. The CGH is composed of essential interference patterns (EIPs). Each EIP records the information of different object points. The resolution of the EIP is reduced. In the reconstructed process, the boundaries of the diffraction light of each EIP and FOV of the reconstructed image are parallel with each other...
November 10, 2016: Applied Optics
https://www.readbyqxmd.com/read/27847867/multicolor-3d-meta-holography-by-broadband-plasmonic-modulation
#11
Xiong Li, Lianwei Chen, Yang Li, Xiaohu Zhang, Mingbo Pu, Zeyu Zhao, Xiaoliang Ma, Yanqin Wang, Minghui Hong, Xiangang Luo
As nanofabrication technology progresses, the emerging metasurface has offered unique opportunities for holography, such as an increased data capacity and the realization of polarization-sensitive functionality. Multicolor three-dimensional (3D) meta-hologram imaging is one of the most pursued applications for meta-hologram not yet realized. How to reduce the cross-talk among different colors in broad bandwidth designs is a critical question. On the basis of the off-axis illumination method, we develop a novel way to overcome the cross-talk limitation and achieve multicolor meta-holography with a single type of plasmonic pixel...
November 2016: Science Advances
https://www.readbyqxmd.com/read/27847847/inter-observer-agreement-between-2-dimensional-ct-versus-3-dimensional-i-space-model-in-the-diagnosis-of-occult-scaphoid-fractures
#12
Tessa Drijkoningen, Robert Knoter, Emile G Coerkamp, Anton H J Koning, Steven J Rhemrev, Frank J Beeres
BACKGROUND: The I-Space is a radiological imaging system in which Computed Tomography (CT)-scans can be evaluated as a three dimensional hologram. The aim of this study is to analyze the value of virtual reality (I-Space) in diagnosing acute occult scaphoid fractures. METHODS: A convenient cohort of 24 patients with a CT-scan from prior studies, without a scaphoid fracture on radiograph, yet high clinical suspicion of a fracture, were included in this study. CT-scans were evaluated in the I-Space by 7 observers of which 3 observers assessed the scans in the I-Space twice...
October 2016: Archives of Bone and Joint Surgery
https://www.readbyqxmd.com/read/27828515/phenomenological-modeling-of-nonlinear-holograms-based-on-metallic-geometric-metasurfaces
#13
Weimin Ye, Xin Li, Juan Liu, Shuang Zhang
Benefiting from efficient local phase and amplitude control at the subwavelength scale, metasurfaces offer a new platform for computer generated holography with high spatial resolution. Three-dimensional and high efficient holograms have been realized by metasurfaces constituted by subwavelength meta-atoms with spatially varying geometries or orientations. Metasurfaces have been recently extended to the nonlinear optical regime to generate holographic images in harmonic generation waves. Thus far, there has been no vector field simulation of nonlinear metasurface holograms because of the tremendous computational challenge in numerically calculating the collective nonlinear responses of the large number of different subwavelength meta-atoms in a hologram...
October 31, 2016: Optics Express
https://www.readbyqxmd.com/read/27828478/architecting-new-diffraction-resistant-light-structures-and-their-possible-applications-in-atom-guidance
#14
E G P Pachon, M Z Amboni-Rached, A H Dorrah, Mo Mojahedi, M R R Gesualdi, G G Cabrera
In this work we extend the so called frozen wave method in order to obtain new diffraction resistant light structures that can be shaped on demand, with possible applications in atom guidance. The resulting beams and the corresponding optical dipole potentials exhibit a strong resistance to diffraction effects and their longitudinal and transverse intensity patterns can be chosen a priori. Besides the theoretical development, we also present the experimental confirmation of our approach; specifically, by generating three different beam profiles using a spatial light modulator that is addressed by a computer-generated hologram...
October 31, 2016: Optics Express
https://www.readbyqxmd.com/read/27828470/acceleration-of-the-calculation-speed-of-computer-generated-holograms-using-the-sparsity-of-the-holographic-fringe-pattern-for-a-3d-object
#15
Hak Gu Kim, Hyunwook Jeong, Yong Man Ro
In computer-generated hologram (CGH) calculations, a diffraction pattern needs to be calculated from all points of a 3-D object, which requires a heavy computational cost. In this paper, we propose a novel fast computer-generated hologram calculation method using sparse fast Fourier transform. The proposed method consists of two steps. First, the sparse dominant signals of CGHs are measured by calculating a wavefront on a virtual plane between the object and the CGH plane. Second, the wavefront on CGH plane is calculated by using the measured sparsity with sparse Fresnel diffraction...
October 31, 2016: Optics Express
https://www.readbyqxmd.com/read/27828461/phase-retrieval-method-for-digital-holography-with-two-cameras-in-particle-measurement
#16
Yohsuke Tanaka, Shunsuke Tani, Shigeru Murata
This paper presents a phase retrieval method for digital holography with two high-speed cameras in particle measurement. The conditions for recording two holograms are derived theoretically. We focus in particular on the distance between the two holograms. The relative misalignment of the two holograms is also evaluated by numerical simulations. Finally, we experimentally compared settling particles reconstructed by the presented method and the Gabor method.
October 31, 2016: Optics Express
https://www.readbyqxmd.com/read/27828405/generation-of-complementary-sampled-phase-only-holograms
#17
P W M Tsang, Y T Chow, T-C Poon
If an image is uniformly down-sampled into a sparse form and converted into a hologram, the phase component alone will be adequate to reconstruct the image. However, the appearance of the reconstructed image is degraded with numerous empty holes. In this paper, we present a low complexity and non-iterative solution to this problem. Briefly, two phase-only holograms are generated for an image, each based on a different down-sampling lattice. Subsequently, the holograms are displayed alternately at high frame rate...
October 3, 2016: Optics Express
https://www.readbyqxmd.com/read/27828347/high-accuracy-method-for-holographic-image-projection-with-suppressed-speckle-noise
#18
Hui Pang, Jiazhou Wang, Axiu Cao, Qiling Deng
Iterative Fourier transform algorithms are widely used for creating holograms in holographic image projection. However, the reconstructed image always suffers from the speckle noise severely due to the uncontrolled phase distribution of the image. In this paper, a new iterative method is proposed to eliminate the speckle noise. In the iteration, the amplitude and phase in the signal window in the output plane are constrained to the desired distribution and a special object-dependent quadratic phase distribution, respectively...
October 3, 2016: Optics Express
https://www.readbyqxmd.com/read/27828323/holography-with-a-neutron-interferometer
#19
Dusan Sarenac, Michael G Huber, Benjamin Heacock, Muhammad Arif, Charles W Clark, David G Cory, Chandra B Shahi, Dmitry A Pushin
We use a Mach-Zehnder interferometer to perform neutron holography of a spiral phase plate. The object beam passes through a spiral phase plate, acquiring the phase twist characteristic of orbital angular momentum states. The reference beam passes through a fused silica prism, acquiring a linear phase gradient. The resulting hologram is a fork dislocation image, which could be used to reconstruct neutron beams with various orbital angular momenta. This work paves the way for novel applications of neutron holography, diffraction and imaging...
October 3, 2016: Optics Express
https://www.readbyqxmd.com/read/27828236/bayesian-approach-to-analyzing-holograms-of-colloidal-particles
#20
Thomas G Dimiduk, Vinothan N Manoharan
We demonstrate a Bayesian approach to tracking and characterizing colloidal particles from in-line digital holograms. We model the formation of the hologram using Lorenz-Mie theory. We then use a tempered Markov-chain Monte Carlo method to sample the posterior probability distributions of the model parameters: particle position, size, and refractive index. Compared to least-squares fitting, our approach allows us to more easily incorporate prior information about the parameters and to obtain more accurate uncertainties, which are critical for both particle tracking and characterization experiments...
October 17, 2016: Optics Express
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