Read by QxMD icon Read


Jean-Nicolas Longchamp, Stephan Rauschenbach, Sabine Abb, Conrad Escher, Tatiana Latychevskaia, Klaus Kern, Hans-Werner Fink
Imaging single proteins has been a long-standing ambition for advancing various fields in natural science, as for instance structural biology, biophysics, and molecular nanotechnology. In particular, revealing the distinct conformations of an individual protein is of utmost importance. Here, we show the imaging of individual proteins and protein complexes by low-energy electron holography. Samples of individual proteins and protein complexes on ultraclean freestanding graphene were prepared by soft-landing electrospray ion beam deposition, which allows chemical- and conformational-specific selection and gentle deposition...
January 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
Pascal Picart, Silvio Montresor, Oleksandr Sakharuk, Leonid Muravsky
This Letter presents an alternative approach for image refocusing in digital Fresnel holography. In the literature, a large majority of reported focus detection criteria is based on amplitude contrast or phase contrast. We propose a focus detection criterion based on the speckle phase coherence factor. This factor reaches its maximum value at the best focus distance. At any reconstruction distance, estimation of the coherence factor is based on robust noise estimation from anisotropic diffusion. We propose a theoretical relation to estimate the coherence factor from the measured standard deviation...
January 15, 2017: Optics Letters
Chao Li, Bin Gao, Yuan Yao, Xiangxiang Guan, Xi Shen, Yanguo Wang, Peng Huang, Lifeng Liu, Xiaoyan Liu, Junjie Li, Changzhi Gu, Jinfeng Kang, Richeng Yu
Resistive switching processes in HfO2 are studied by electron holography and in situ energy-filtered imaging. The results show that oxygen vacancies are gradually generated in the oxide layer under ramped electrical bias, and finally form several conductive channels connecting the two electrodes. It also shows that the switching process occurs at the top interface of the hafnia layer.
January 11, 2017: Advanced Materials
Nir A Turko, Natan T Shaked
We present a dual-wavelength external holographic microscopy module for quantitative phase imaging of 3D structures with extended thickness range. This is done by simultaneous acquisition of two off-axis interferograms, each at a different wavelength, and generation of a synthetic wavelength, which is larger than the sample optical thickness, allowing two-wavelength unwrapping. The simultaneous acquisition is carried out by using optical multiplexing of the two interferograms onto the camera, where each of them has orthogonal off-axis interference fringe direction in relation to the other one...
January 1, 2017: Optics Letters
Mahsa Asgarisabet, Andrew R Barnard, Troy M Bouman
Carbon nanotube (CNT) thin film speakers produce sound with the thermoacoustic effect. Better understanding of the physical acoustic properties of these speakers will drive future design improvements. Measuring acoustic properties at the surface of the CNT thin film is difficult because the films, themselves, do not vibrate, are fragile and have a high surface temperature. In order to measure the surface particle velocity and sound pressure level (SPL), near field acoustic holography (NAH) has been used by employing probe microphones...
December 2016: Journal of the Acoustical Society of America
Dimitris G Papazoglou, Vladimir Yu Fedorov, Stelios Tzortzakis
We show the existence of a family of waves that share a common interesting property affecting the way these waves propagate and focus. The waves are a superposition of twin waves, which are conjugate to each other under inversion of the propagation direction. In analogy to holography, these twin "real" and "virtual" waves are related, respectively, to the converging and diverging parts of the beam and can be clearly visualized in real space at two distinct foci under the action of a focusing lens. Analytic formulas for the intensity distribution after focusing are derived, while numerical and experimental demonstrations are given for some of the most interesting members of this family, the accelerating Airy and ring-Airy beams...
October 15, 2016: Optics Letters
Colin Ophus, Haider I Rasool, Martin Linck, Alex Zettl, Jim Ciston
We develop an automatic and objective method to measure and correct residual aberrations in atomic-resolution HRTEM complex exit waves for crystalline samples aligned along a low-index zone axis. Our method uses the approximate rotational point symmetry of a column of atoms or single atom to iteratively calculate a best-fit numerical phase plate for this symmetry condition, and does not require information about the sample thickness or precise structure. We apply our method to two experimental focal series reconstructions, imaging a β-Si3N4 wedge with O and N doping, and a single-layer graphene grain boundary...
2017: Advanced Structural and Chemical Imaging
Guannan Chen, Mingli Ni, Haiyan Peng, Feihong Huang, Yonggui Liao, Mingkui Wang, Jintao Zhu, V A L Roy, Xiaolin Xie
Holographic photopolymer composites have garnered a great deal of interest in recent decades, not only because of their advantageous light sensitivity but also due to their attractive capabilities of realizing high capacity three-dimensional (3D) data storage that is long-term stable within two-dimensional (2D) thin films. For achieving high performance holographic photopolymer composites, it is of critical importance to implement precisely spatiotemporal control over the photopolymerization kinetics and gelation during holographic recording...
January 18, 2017: ACS Applied Materials & Interfaces
Yi Yu, Dandan Zhang, Christian Kisielowski, Letian Dou, Nikolay Kornienko, Yehonadav Bekenstein, Andrew B Wong, A Paul Alivisatos, Peidong Yang
The radiation-sensitive nature of halide perovskites has hindered structural studies at the atomic scale. We overcome this obstacle by applying low dose-rate in-line holography, which combines aberration-corrected high-resolution transmission electron microscopy with exit-wave reconstruction. This technique successfully yields the genuine atomic structure of ultrathin two-dimensional CsPbBr3 halide perovskites, and a quantitative structure determination was achieved atom column by atom column using the phase information of the reconstructed exit-wave function without causing electron beam-induced sample alterations...
December 14, 2016: Nano Letters
Amin Moradi, Ehsan A Akhlaghi, Faegheh Hajizedeh, S Nader S Reihani
Here we introduce a phase-shifting digital holography-based method to determine the temperature profile around an irradiated (sub-)micron spherical bead. The method utilizes a Mach-Zehnder interferometer implemented into an open setup microscope. The results of irradiated gold spheres with diameter of 400 nm and also silver-coated micron-sized silica beads embedded in silicone oil are presented. We show that the applied method is able to accurately determine the surface temperature with accuracy of 1 °C. Our experimental results perfectly confirm the theoretical prediction of temperature profile around the irradiated bead...
December 12, 2016: Optics Express
Farnoud Kazemzadeh, Alexander Wong
Wide-field lensfree on-chip microscopy, which leverages holography principles to capture interferometric light-field encodings without lenses, is an emerging imaging modality with widespread interest given the large field-of-view compared to lens-based techniques. In this study, we introduce the idea of laser light-field fusion for lensfree on-chip phase contrast microscopy for detecting nanoparticles, where interferometric laser light-field encodings acquired using a lensfree, on-chip setup with laser pulsations at different wavelengths are fused to produce marker-free phase contrast images of particles at the nanometer scale...
December 13, 2016: Scientific Reports
Kazuo Yamamoto, Yasutoshi Iriyama, Tsukasa Hirayama
No abstract text is available yet for this article.
December 6, 2016: Microscopy
Tsukasa Hirayama, Yuka Aizawa, Kazuo Yamamoto, Takeshi Sato, Hidekazu Murata, Ryuji Yoshida, Craig A J Fisher, Takehisa Kato, Yasutoshi Iriyama
Advanced techniques for overcoming problems encountered during in situ electron holography experiments in which a voltage is applied to an ionic conductor are reported. The three major problems encountered were 1) electric-field leakage from the specimen and its effect on phase images, 2) high electron conductivity of damage layers formed by the focused ion beam method, and 3) chemical reaction of the specimen with air. The first problem was overcome by comparing experimental phase distributions with simulated images in which three-dimensional leakage fields were taken into account, the second by removing the damage layers using a low-energy narrow Ar ion beam, and the third by developing an air-tight biasing specimen holder...
November 29, 2016: Ultramicroscopy
Diange Yang, Junjie Wen, Feng Miao, Ziteng Wang, Xiaoan Gu, Xiaomin Lian
Identification and measurement of moving sound sources are the bases for vehicle noise control. Acoustic holography has been applied in successfully identifying the moving sound source since the 1990s. However, due to the high demand for the accuracy of holographic data, currently the maximum velocity achieved by acoustic holography is just above 100 km/h. The objective of this study was to establish a method based on the complete Morse acoustic model to restore the measured signal in high-speed situations, and to propose a far-field acoustic holography method applicable for high-speed moving sound sources...
September 2016: Journal of the Acoustical Society of America
Anton Krynkin, Kirill V Horoshenkov, Timothy Van Renterghem
Currently, there is no airborne in situ method to reconstruct with high fidelity the instantaneous elevation of a dynamically rough surface of a turbulent flow. This work proposes a holographic method that reconstructs the elevation of a one-dimensional rough water surface from airborne acoustic pressure data. This method can be implemented practically using an array of microphones deployed over a dynamically rough surface or using a single microphone which is traversed above the surface at a speed that is much higher than the phase velocity of the roughness pattern...
September 2016: Journal of the Acoustical Society of America
C E Tommy Thomas, T M Biewer, L R Baylor, S K Combs, S J Meitner, J Rapp, D L Hillis, E M Granstedt, R Majeski, R Kaita
A project has been started at ORNL to develop a dual-wavelength digital holography system for plasma facing component erosion measurements on prototype material plasma exposure experiment. Such a system will allow in situ real-time measurements of component erosion. Initially the system will be developed with one laser, and first experimental laboratory measurements will be made with the single laser system. In the second year of development, a second CO2 laser will be added and measurements with the dual wavelength system will begin...
November 2016: Review of Scientific Instruments
Rajib Ahmed, Ali K Yetisen, Anthony El Khoury, Haider Butt
Advances in holography have led to applications including data storage, displays, security labels, and colorimetric sensors. However, existing top-down approaches for the fabrication of holographic devices are complex, expensive, and expertise dependent, limiting their use in practical applications. Here, ink-based holographic devices have been created for a wide range of applications in diffraction optics. A single pulse of a 3.5 ns Nd:YAG laser allowed selective ablation of ink to nanofabricate planar optical devices...
January 7, 2017: Nanoscale
Masahiro Yamaguchi
A perfect three-dimensional (3D) display that satisfies all depth cues in human vision is possible if a light field can be reproduced exactly as it appeared when it emerged from a real object. The light field can be generated based on either light ray or wavefront reconstruction, with the latter known as holography. This paper first provides an overview of the advances of ray-based and wavefront-based 3D display technologies, including integral photography and holography, and the integration of those technologies with digital information systems...
December 1, 2016: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
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
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
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"