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Vimal Prabhu Pandiyan, Kedar Khare, Renu John
No abstract text is available yet for this article.
October 1, 2016: Journal of Biomedical Optics
Wei Luo, Yibo Zhang, Zoltán Göröcs, Alborz Feizi, Aydogan Ozcan
No abstract text is available yet for this article.
October 19, 2016: Scientific Reports
Mehdi Molaei, Jian Sheng
Understanding how bacteria move close to a surface under various stimuli is crucial for a broad range of microbial processes including biofilm formation, bacterial transport and migration. While prior studies focus on interactions between single stimulus and bacterial suspension, we emphasize on compounding effects of flow shear and solid surfaces on bacterial motility, especially reorientation and tumble. We have applied microfluidics and digital holographic microscopy to capture a large number (>10(5)) of 3D Escherichia coli trajectories near a surface under various flow shear...
October 18, 2016: Scientific Reports
Yangbo Xie, Chen Shen, Wenqi Wang, Junfei Li, Dingjie Suo, Bogdan-Ioan Popa, Yun Jing, Steven A Cummer
Acoustic holographic rendering in complete analogy with optical holography are useful for various applications, ranging from multi-focal lensing, multiplexed sensing and synthesizing three-dimensional complex sound fields. Conventional approaches rely on a large number of active transducers and phase shifting circuits. In this paper we show that by using passive metamaterials as subwavelength pixels, holographic rendering can be achieved without cumbersome circuitry and with only a single transducer, thus significantly reducing system complexity...
October 14, 2016: Scientific Reports
Anna Wang, Ryan McGorty, David M Kaz, Vinothan N Manoharan
Previous experiments have shown that spherical colloidal particles relax to equilibrium slowly after they adsorb to a liquid-liquid interface, despite the large interfacial energy gradient driving the adsorption. The slow relaxation has been explained in terms of transient pinning and depinning of the contact line on the surface of the particles. However, the nature of the pinning sites has not been investigated in detail. We use digital holographic microscopy to track a variety of colloidal spheres-inorganic and organic, charge-stabilized and sterically stabilized, aqueous and non-aqueous-as they breach liquid interfaces...
October 13, 2016: Soft Matter
Anouar Rahmouni, Yahya Bougdid, Sara Moujdi, Dmitry V Nesterenko, Zouheir Sekkat
Holographic storage is one of the most important applications in the field of optics, especially for recording and retrieving data, and information storage by interference patterns in photosensitive materials are no exception in this regard. In this work, we give evidence that holograms recorded by interference of two-coherent laser beams in azo dye doped polymer films can be controlled by a third incoherent assisting laser beam. We show that light diffraction can be increased or decreased by an assisting beam depending on the respective orientation of the polarizations of the recording and the assisting beams...
October 11, 2016: Journal of Physical Chemistry. B
Khaled M Yassien, Mostafa Agour
A method for studying the effect of temperature on the optical properties of basalt fiber is presented. It is based on recording a set of phase-shifted digital holograms for the sample under the test. The holograms are obtained utilizing a system based on Mach-Zehnder interferometer, where the fiber sample inserted in an immersion liquid is placed within a temperature controlled chamber. From the recorded digital holograms the optical path differences which are used to calculate the refractive indices are determined...
October 11, 2016: Microscopy Research and Technique
Chen Wang, Fook Chiong Cheong, David B Ruffner, Xiao Zhong, Michael D Ward, David G Grier
In-line holographic microscopy images of micrometer-scale fractal aggregates can be interpreted with an effective-sphere model to obtain each aggregate's size and the population-averaged fractal dimension. We demonstrate this technique experimentally using model fractal clusters of polystyrene nanoparticles and fractal protein aggregates composed of bovine serum albumin and bovine pancreas insulin.
October 5, 2016: Soft Matter
Alexander Ryabchun, Matthias Kollosche, Michael Wegener, Oksana Sakhno
Volume diffraction gratings (VDGs) are inscribed selectively by diffusive introduction of benzophenone and subsequent UV-holographic structuring into an electroactive dielectric elastomer actuator (DEA), to afford a continuous voltage-controlled grating shift of 17%. The internal stress coupling of DEA and optical domain allows for a new generation of true monolithic tunable elastomer optics with voltage controlled properties.
October 7, 2016: Advanced Materials
Alborz Feizi, Yibo Zhang, Alon Greenbaum, Alex Guziak, Michelle Luong, Raymond Yan Lok Chan, Brandon Berg, Haydar Ozkan, Wei Luo, Michael Wu, Yichen Wu, Aydogan Ozcan
Monitoring yeast cell viability and concentration is important in brewing, baking and biofuel production. However, existing methods of measuring viability and concentration are relatively bulky, tedious and expensive. Here we demonstrate a compact and cost-effective automatic yeast analysis platform (AYAP), which can rapidly measure cell concentration and viability. AYAP is based on digital in-line holography and on-chip microscopy and rapidly images a large field-of-view of 22.5 mm(2). This lens-free microscope weighs 70 g and utilizes a partially-coherent illumination source and an opto-electronic image sensor chip...
September 30, 2016: Lab on a Chip
P W M Tsang, T-C Poon, J-P Liu, T Kim, Y S Kim
In this paper we report a low complexity compression method that is suitable for compact optical scanning holography (OSH) systems with different optical settings. Our proposed method can be divided into 2 major parts. First, an automatic decision maker is applied to select the rows of holographic pixels to be scanned. This process enhances the speed of acquiring a hologram, and also lowers the data rate. Second, each row of down-sampled pixels is converted into a one-bit representation with delta modulation (DM)...
October 6, 2016: Scientific Reports
Alexis D J Makin, Damien Wright, Giulia Rampone, Letizia Palumbo, Martin Guest, Rhiannon Sheehan, Helen Cleaver, Marco Bertamini
A traditional line of work starting with the Gestalt school has shown that patterns vary in strength and salience; a difference in "Perceptual goodness." The Holographic weight of evidence model quantifies goodness of visual regularities. The key formula states that W = E/N, where E is number of holographic identities in a pattern and N is number of elements. We tested whether W predicts the amplitude of the neural response to regularity in an extrastriate symmetry-sensitive network. We recorded an Event Related Potential (ERP) generated by symmetry called the Sustained Posterior Negativity (SPN)...
October 4, 2016: Cerebral Cortex
Koki Wakunami, Po-Yuan Hsieh, Ryutaro Oi, Takanori Senoh, Hisayuki Sasaki, Yasuyuki Ichihashi, Makoto Okui, Yi-Pai Huang, Kenji Yamamoto
Owing to the limited spatio-temporal resolution of display devices, dynamic holographic three-dimensional displays suffer from a critical trade-off between the display size and the visual angle. Here we show a projection-type holographic three-dimensional display, in which a digitally designed holographic optical element and a digital holographic projection technique are combined to increase both factors at the same time. In the experiment, the enlarged holographic image, which is twice as large as the original display device, projected on the screen of the digitally designed holographic optical element was concentrated at the target observation area so as to increase the visual angle, which is six times as large as that for a general holographic display...
October 3, 2016: Nature Communications
Philipp Lenz, Markus Brückner, Steffi Ketelhut, Jan Heidemann, Björn Kemper, Dominik Bettenworth
The incidence of inflammatory bowel disease, i.e., Crohn's disease and Ulcerative colitis, has significantly increased over the last decade. The etiology of IBD remains unknown and current therapeutic strategies are based on the unspecific suppression of the immune system. The development of treatments that specifically target intestinal inflammation and epithelial wound healing could significantly improve management of IBD, however this requires accurate detection of inflammatory changes. Currently, potential drug candidates are usually evaluated using animal models in vivo or with cell culture based techniques in vitro...
2016: Journal of Visualized Experiments: JoVE
C Grassberger, P Dinkelborg, A McNamara, J P Schuemann, S J McMahon, H Willers, H Paganetti, M Wang
No abstract text is available yet for this article.
October 1, 2016: International Journal of Radiation Oncology, Biology, Physics
Nicholas Hoai Nam Nguyen
PURPOSE: To evaluate the performance of a holographic logMAR chart for the subjective spherical refraction of the human eye. METHODS: Bland-Altman analysis was used to assess the level of agreement between subjective spherical refraction using the holographic logMAR chart and conventional autorefraction and subjective spherical refraction. RESULTS: The 95% limits of agreement (LoA) were calculated between holographic refraction and the two standard methods (subjective and autorefraction)...
October 2016: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Dilband Muhammad, Cuong M Nguyen, Jihoon Lee, Hyuk-Sang Kwon
We present a spatially incoherent dual path Fourier holographic system. Conceptually it is similar to Fourier incoherent single channel holography (FISCH). Although our incoherent off-axis Fourier holographic (IOFH) system does not have the robustness of a single channel system, it has three advantages over FISCH, with two being quite obvious from setup. First, no SLM is required, thus making the system simple and cost-effective. Second, it is capable of high light throughput because in FISCH, the use of SLM reduces light intensity in half by splitting one beam into two; furthermore, an analyzer is required to create interference which also reduces light intensity...
September 19, 2016: Optics Express
I S Wahyutama, G K Tadesse, A Tünnermann, J Limpert, J Rothhardt
Lensless coherent diffractive imaging usually requires iterative phase-retrieval for recovering the missing phase information. Holographic techniques, such as Fourier-transform holography (FTH) or holography with extended references (HERALDO), directly provide this phase information and thus allow for a direct non-iterative reconstruction of the sample. In this paper, we analyze the effect of detector noise on the reconstruction for FTH and HERALDO with linear and rectangular references. We find that HERALDO is more sensitive to this type of noise than FTH, especially if rectangular references are employed...
September 19, 2016: Optics Express
Geminiano Martinez-Ponce
Three types of polarization gratings have been recorded in azopolymer films by the symmetrical superposition of different orthogonal pairs of polarized beams. The inscribed holographic elements have been analyzed microscopically in a Mueller polarimeter in order to image the optical anisotropies photoinduced in the film. In the most of cases, the spatial modulation of diattenuation, birefringence, and optical rotation reproduced quite well previous results reported in the literature. Nevertheless, in the particular case of coherent superposition of p- and s-polarized beams, the spatial frequency for optical rotation (related to the Stokes parameter V) was different from the one observed in linear anisotropy (related to the Stokes parameter U)...
September 19, 2016: Optics Express
Liang Han, Wen-Li Zhang, Xiujuan Pu, Wanqi Cheng, Xia Liu
The nonsubsampled contourlet transform (NSCT) is a fully shift-invariant, multiscale, and multidirectional expansion implemented in optics using the Fourier transform of its filters. In this paper, we propose a novel optical NSCT filter design method and the corresponding post-processing method to avoid the use of holographic techniques. The novel optical NSCT filter has real and non-negative Fourier transforms. The input image is placed in the input plane of the VanderLugt 4f correlator, and these real and non-negative Fourier transform NSCT filters are placed in the frequency plane of the VanderLugt 4f correlator...
September 20, 2016: Applied Optics
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