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Eva Déli, Arturo Tozzi, James F Peters
Brain electric activity exhibits two important features: oscillations with different timescales, characterized by diverse functional and psychological outcomes, and a temporal power law distribution. In order to further investigate the relationships between low- and high- frequency spikes in the brain, we used a variant of the Borsuk-Ulam theorem which states that, when we assess the nervous activity as embedded in a sphere equipped with a fractal dimension, we achieve two antipodal points with similar features (the slow and fast, scale-free oscillations)...
December 2017: Cognitive Neurodynamics
Praneet Prakash, Manoj Varma
Suspensions of micro/nano particles made of Polystyrene, Poly(methyl methacrylate), Silicon dioxide etc. have been a standard model system to understand colloidal physics. These systems have proved useful insights into phenomena such as self-assembly. Colloidal model systems are also extensively used to simulate many condensed matter phenomena such as dynamics in a quenched disordered system and glass transition. A precise control of particles using optical or holographic tweezers is essential for such studies...
November 16, 2017: Scientific Reports
Preston R Huft, Joshua D Kolbow, Jonathan T Thweatt, Nathan C Lindquist
We demonstrate dynamic trapping and manipulation of nanoparticles with plasmonic holograms. By tailoring the illumination pattern of an incident light beam with a computer-controlled spatial light modulator, constructive and destructive interference of plasmon waves create a focused hotspot that can be moved across a surface. Specifically, a computer-generated hologram illuminating the perimeter of a silver Bull's Eye nanostructure generates surface plasmons that propagate towards the center. Shifting the phase of the plasmon waves as a function of space gives complete control over the location of the focus...
November 16, 2017: Nano Letters
Eric F Bernstein, Kevin T Schomacker, Amit S Paranjape, Jayant D Bhawalkar
<p>BACKGROUND: A dual-wavelength, picosecond-domain, fractionated laser delivering 1,064nm and 532nm laser energy through a holographic optic was investigated for safety and effectiveness at improving the appearance of chronic photoaging. MATERIALS AND METHODS: A total of 27 subjects were enrolled with 24 completing the study, and 14 subjects were treated with 1,064 nm and 10 with 532 nm. The 1,064 nm-treated subjects received 5 monthly treatments while the 532 nm-treated subjects received 4 monthly treatments...
November 1, 2017: Journal of Drugs in Dermatology: JDD
Gita Khalili Moghaddam, Christopher Robin Lowe
The research reported herein integrates a generic holographic sensor platform and a smartphone-based colour quantification algorithm in order to standardise and improve the determination of the concentration of analytes of interest. The utility of this approach has been exemplified by analysing the replay colour of the captured image of a holographic pH sensor in near real-time. Personalised image encryption followed by a wavelet-based image compression method were applied to secure the image transfer across a bandwidth-limited network to the cloud...
2017: PloS One
Daryl Preece, Halina Rubinsztein-Dunlop
We develop a basis for three-dimensional rotation of arbitrary light fields created by computer generated holograms. By adding an extra phase function into the kinoform, any light field or holographic image can be tilted in the focal plane with minimized distortion. We present two different approaches to rotate an arbitrary hologram: the Scheimpflug method and a novel coordinate transformation method. Experimental results are presented to demonstrate the validity of both proposed methods.
November 15, 2017: Optics Letters
Dmitry V Petrov, Alexey R Zaripov, Nikita A Toropov
The Letter demonstrates a possibility to enhance the Raman scattering of a gaseous medium due to an enhanced electromagnetic field caused by the excitation of propagating surface plasmon polaritons (PSPPs) on a silver holographic grating. Efficiency of collinear and noncollinear schemes of PSPP excitation on a metal-gaseous medium interface was studied. When using a collinear scheme, we registered an eightfold enhancement of the Raman scattering of atmospheric nitrogen and oxygen, where the average gain near the PSPP-active surface was ∼4×10(3)...
November 15, 2017: Optics Letters
Moran Rubin, Gili Dardikman, Simcha K Mirsky, Nir A Turko, Natan T Shaked
We present a new holographic concept, named six-pack holography (6PH), in which we compress six off-axis holograms into a single multiplexed off-axis hologram without loss of magnification or resolution. The multiplexed hologram contains straight off-axis fringes with six different orientations, and can be generated optically or digitally. We show that since the six different complex wavefronts do not overlap in the spatial frequency domain, they can be fully reconstructed. 6PH allows more than 50% improvement in the spatial bandwidth consumption when compared to the best multiplexing method proposed so far...
November 15, 2017: Optics Letters
Hongpeng Liu, Dan Yu, Ke Zhou, Shichan Wang, Suhua Luo, Weibo Wang, Qinggong Song
A novel thermo-sensitive N-isopropylacrylamide photopolymer was developed for improving the temperature and humidity responses of holographic sensors. Diffraction spectra of holographic volume gratings recorded in the materials were characterized to explore the sensing response capacity. A dependence of peak wavelength on the temperature was observed and provided a quantitative strategy for holographic sensing applications. Expansion of the humidity range induced a strong extension of wavelength shift. Finally, the temperature response reversibility was demonstrated experimentally...
November 10, 2017: Applied Optics
Juanjuan Zheng, Peng Gao, Xiaopeng Shao, G Ulrich Nienhaus
Opposed-view digital holographic microscopy (OV-DHM) with autofocusing and out-of-focus background suppression was demonstrated and applied to measure the refractive index (RI) of suspended HeLa cells. In OV-DHM, a specimen is illuminated from two sides in a 4π-like configuration. The generated two opposite-view object waves, which have orthogonal polarization orientations, interfere with a common reference wave, and the generated holograms are recorded by a CMOS camera. The image plane of the sample was determined by finding the minimal variation between the two object waves...
November 10, 2017: Applied Optics
Michael O Vertolli, Matthew A Kelly, Jim Davies
An incoherent visualization is when aspects of different senses of a word (e.g., the biological "mouse" vs. the computer "mouse") are present in the same visualization (e.g., a visualization of a biological mouse in the same image with a computer tower). We describe and implement a new model of creating contextual coherence in the visual imagination called Coherencer, based on the SOILIE model of imagination. We show that Coherencer is able to generate scene descriptions that are more coherent than SOILIE's original approach as well as a parallel connectionist algorithm that is considered competitive in the literature on general coherence...
November 10, 2017: Cognitive Science
Owen G Rehrauer, Vu C Dinh, Bharat R Mankani, Gregery T Buzzard, Bradley J Lucier, Dor Ben-Amotz
The previously described optimized binary compressive detection (OB-CD) strategy enables fast hyperspectral Raman (and fluorescence) spectroscopic analysis of systems containing two or more chemical components. However, each OB-CD filter collects only a fraction of the scattered photons and the remainder of the photons are lost. Here, we present a refinement of OB-CD, the OB-CD2 strategy, in which all of the collected Raman photons are detected using a pair of complementary binary optical filters that direct photons of different colors to two photon counting detectors...
January 1, 2017: Applied Spectroscopy
Emil Tanghetti, John Jennings
BACKGROUND AND OBJECTIVES: This study was performed to better understand the cutaneous effects of using a fractional picosecond laser at 755 nm with a diffractive lens array and a picosecond Nd:YAG laser at 532 mn and 1,064 nm with a holographic optic. We characterized the injuries created by these devices on skin clinically and histologically over 24 hours. With this information we modeled the effects of these devices on a cutaneous target. METHODS: Eight patients, representing Fitzpatrick skin types I-VI, were treated on their backs with a picosecond Alexandrite laser with a diffractive lens array, as well as a picosecond Nd:YAG laser at 532 nm and 1,064 nm with a holographic optic...
November 7, 2017: Lasers in Surgery and Medicine
Mathias Kaiser, Luisa Pohl, Steffi Ketelhut, Lena Kastl, Christian Gorzelanny, Martin Götte, Jürgen Schnekenburger, Francisco M Goycoolea, Björn Kemper
We have developed a drug delivery nanosystem based on chitosan and capsaicin. Both substances have a wide range of biological activities. We investigated the nanosystem's influence on migration and morphology of Madin Darby canine kidney (MDCK-C7) epithelial cells in comparison to the capsaicin-free nanoformulation, free capsaicin, and control cells. For minimally-invasive quantification of cell migration, we applied label-free digital holographic microscopy (DHM) and single-cell tracking. Moreover, quantitative DHM phase images were used as novel stain-free assay to quantify the temporal course of global cellular morphology changes in confluent cell layers...
2017: PloS One
Sun Il Kim, Chil-Sung Choi, Alexander Morozov, Sergey Dubynin, German Dubinin, Jungkweun An, Sung-Hoon Lee, Young Kim, Kanghee Won, Hoon Song, Hong-Seok Lee, Sungwoo Hwang
The coherent backlight unit (BLU) using a holographic optical element (HOE) for full-color flat-panel holographic display is proposed. The HOE BLU consists of two reflection type HOEs that change the optical beam path and shape by diffraction. The illumination area of backlight is 150 mm x 90 mm and the thickness is 10 mm, which is slim compared to other conventional coherent backlight units for holographic display systems. This backlight unit exhibits a total efficiency of 8.0% at red (660 nm), 7.7% at green (532 nm), and 3...
October 30, 2017: Optics Express
Nicolas C Pégard, Alan R Mardinly, Ian Antón Oldenburg, Savitha Sridharan, Laura Waller, Hillel Adesnik
Optical methods capable of manipulating neural activity with cellular resolution and millisecond precision in three dimensions will accelerate the pace of neuroscience research. Existing approaches for targeting individual neurons, however, fall short of these requirements. Here we present a new multiphoton photo-excitation method, termed three-dimensional scanless holographic optogenetics with temporal focusing (3D-SHOT), which allows precise, simultaneous photo-activation of arbitrary sets of neurons anywhere within the addressable volume of a microscope...
October 31, 2017: Nature Communications
Faliu Yi, Inkyu Moon, Bahram Javidi
In this paper, we present two models for automatically extracting red blood cells (RBCs) from RBCs holographic images based on a deep learning fully convolutional neural network (FCN) algorithm. The first model, called FCN-1, only uses the FCN algorithm to carry out RBCs prediction, whereas the second model, called FCN-2, combines the FCN approach with the marker-controlled watershed transform segmentation scheme to achieve RBCs extraction. Both models achieve good segmentation accuracy. In addition, the second model has much better performance in terms of cell separation than traditional segmentation methods...
October 1, 2017: Biomedical Optics Express
Ye Zhang, Bin Deng, Qi Yang, Jingkun Gao, Yuliang Qin, Hongqiang Wang
In this paper, a fast three-dimensional (3-D) frequency scaling algorithm (FSA) with large depth of focus is presented for near-field planar millimeter-wave (MMW) holographic imaging. Considering the cross-range range coupling term which is neglected in the conventional range migration algorithm (RMA), we propose an algorithm performing the range cell migration correction for de-chirped signals without interpolation by using a 3-D frequency scaling operation. First, to deal with the cross-range range coupling term, a 3-D frequency scaling operator is derived to eliminate the space variation of range cell migration...
October 24, 2017: Sensors
Babak Amirsolaimani, Gholam Peyman, Jim Schwiegerling, Arkady Bablumyan, N Peyghambarian
Using a phoropter to measure the refractive error is one of the most commonly used methods by ophthalmologists and optometrists. Here, we demonstrate design and fabrication of a portable automatic phoropter with no need for patient's feedback. The system is based on three tunable-focus fluidic lenses and thin-film holographic optical elements to perform automatic refractive error measurement and provide a diagnostic prescription without supervision. Three separate lenses are deployed to correct the defocus and astigmatism...
October 25, 2017: Scientific Reports
Zhen Wu, Xinke Wang, Wenfeng Sun, Shengfei Feng, Peng Han, Jiasheng Ye, Yan Zhang
As a kind of special beams, Bessel beams are always a research hot spot in optics due to its non-diffractive and self-healing properties. Here, zero-order terahertz (THz) Bessel beams with linear and circular polarizations are generated by using a THz quarter wave plate and Teflon axicons with different opening angles. By applying a THz digital holographic imaging system, the evolutions of the transverse (E x , E y ) and longitudinal (E z ) electric fields are coherently measured and analyzed during the propagation processes of the THz Bessel beams...
October 24, 2017: Scientific Reports
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