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Nowroji Kavitha, Yeng Chen, Jagat R Kanwar, Sreenivasan Sasidharan
Phaleria macrocarpa (Boerl.) is a well-known medicinal plant and have been extensively used as traditional medicine for ages in treatment of various diseases. The purpose of this study was to determine the in situ cytotoxicity effect P. macrocarpa fruit ethyl acetate fraction (PMEAF) by using various conventional and modern microscopy techniques. The cytotoxicity of PMEAF treated MDA-MB-231 cells was determined through the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity assay and CyQuant Cell Proliferation Assay after 24h of treatment...
January 9, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Tobias Meinert, Benjamin Alexander Gutwein, Alexander Rohrbach
Light-sheet microscopy enables fast 3D, high-contrast imaging in biology and colloidal sciences. Recently, the controlled transport of living embryos or small colloids through stable glass capillaries is manifold interesting. Although they hardly impair the sample, glass capillaries spoil the image by generating significant aberrations of the illumination and detection light. Here, we analyze the deflection of illuminating Bessel beams at the capillary by k-spectral shifting, and correct for it by a beam deflector...
January 15, 2017: Optics Letters
Po-Hao Wang, Vijay Raj Singh, Jau-Min Wong, Kung-Bin Sung, Yuan Luo
Confocal imaging techniques offer an optical sectioning capability to acquire three-dimensional information from various volumetric samples by discriminating the desired in-focus signals from the out-of-focus background. However, confocal, in general, requires a point-by-point scan in both the lateral and axial directions to reconstruct three-dimensional images. In addition, axial scanning in confocal is slower than scanning in lateral directions. In this Letter, a non-axial-scanning multifocal confocal microscope incorporating multiplexed holographic gratings in illumination and dual detection for depth discrimination is presented...
January 15, 2017: Optics Letters
Haiting Xia, Silvio Montresor, Rongxin Guo, Junchang Li, François Olchewsky, Jean-Michel Desse, Pascal Picart
This Letter proposes a robust processing of phase dislocations to recover continuous phase maps. The approach is based on combined unwrapping and inpainting methods. Phase dislocations are determined using an estimator based on the second order phase gradient. The algorithm is validated using a realistic simulation of phase dislocations, and the phase restoration exhibits only weak errors. A comparison with other inpainting algorithms is also provided, demonstrating the suitability of the approach. The approach is applied to experimental data from off-axis digital holographic interferometry...
January 15, 2017: Optics Letters
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
Junwei Min, Baoli Yao, Steffi Ketelhut, Christian Engwer, Burkhard Greve, Björn Kemper
We present a simple and fast phase aberration compensation method in digital holographic microscopy (DHM) for quantitative phase imaging of living cells. By analyzing the frequency spectrum of an off-axis hologram, phase aberrations can be compensated for automatically without fitting or pre-knowledge of the setup and/or the object. Simple and effective computation makes the method suitable for quantitative online monitoring with highly variable DHM systems. Results from automated quantitative phase imaging of living NIH-3T3 mouse fibroblasts demonstrate the effectiveness and the feasibility of the method...
January 15, 2017: Optics Letters
Xiaohu Zhang, Jinjin Jin, Mingbo Pu, Xiong Li, Xiaoliang Ma, Ping Gao, Zeyu Zhao, Yanqin Wang, Changtao Wang, Xiangang Luo
For the miniaturization of optical holographic and data recording devices, large information capacity or data density is indispensable but difficult to obtain using traditional technologies. In this paper, an ultrahigh-capacity metasurface hologram is proposed by encoding information in deep-subwavelength scale nanohole arrays, which can be reconstructed via a light beam with proper designed incident angles. The imaging information capacity of the two-dimensional (2D) hologram, defined by the distortion-free region, can be increased 11...
January 11, 2017: Nanoscale
Bader AlQattan, Haider Butt, Aydin Sabouri, Ali K Yetisen, Rajib Ahmed, Nasim Mahmoodi
The development of accurate and rapid techniques to produce nanophotonic structures is essential in data storage, sensors, and spectroscopy. Existing bottom-up and top-down approaches to fabricate nanophotonic devices are high cost and time consuming, limiting their mass manufacturing and practical applications. Here, we demonstrate a strategy to rapidly create 25-40 nm thick 1/2D Au-Ti nanopatterns using holographic direct laser interference patterning (DLIP). Pulses of an Nd:YAG laser (1064 nm) in holographic Denisyuk reflection mode were used to create ablative interference fringes...
December 4, 2016: RSC Advances
Thomas G Folland, Li Hua, Subhasish Chakraborty
Aperiodic lattices are a promising route to achieving tunable or multi-frequency lasing, but their threshold spectrum remains largely unstudied. We find that holographically designed aperiodic lattices can possess a multimode spectral response, containing both defect and band-edge photonic states. Under the influence of facet feedback the aperiodic lattice maintains remarkable spectral control at multiple frequencies over a wide bandwidth. This control arises from enhancement to the photon density of states at the designed frequencies, reducing the threshold of modes in the Fabry Perot coupled aperiodic lattice laser...
December 26, 2016: Optics Express
Bo E Miller, Yuzuru Takashima
Resonant optical cavities have been demonstrated to improve energy efficiencies in Holographic Data Storage Systems (HDSS). The orthogonal reference beams supported as cavity eigenmodes can provide another multiplexing degree of freedom to push storage densities toward the limit of 3D optical data storage. While keeping the increased energy efficiency of a cavity enhanced reference arm, image bearing holograms are multiplexed by orthogonal phase code multiplexing via Hermite-Gaussian eigenmodes in a Fe:LiNbO<sub>3</sub> medium with a 532 nm laser at two Bragg angles...
December 26, 2016: Optics Express
Yijun Qi, Chenliang Chang, Jun Xia
The purpose of this study is to implement speckle reduced three-dimensional (3-D) holographic display by single phase-only spatial light modulator (SLM). The complex amplitude of hologram is transformed to pure phase value based on double-phase method. To suppress noises and higher order diffractions, we introduced a 4-f system with a filter at the frequency plane. A blazing grating is proposed to separate the complex amplitude on the frequency plane. Due to the complex modulation, the speckle noise is reduced...
December 26, 2016: Optics Express
S Schmidt, T Tiess, S Schröter, R Hambach, M Jäger, H Bartelt, A Tünnermann, H Gross
The optical design and analysis of modern micro-optical elements with high index contrasts and large numerical apertures is still challenging, as fast and accurate wave-optical simulations beyond the thin-element-approximation are required. We introduce a modified formulation of the wave-propagation-method and assess its performance in comparison to different beam-propagation-methods with respect to accuracy, required sampling densities, and computational performance. For typical micro-optical components, the wave-propagation-method is found to be considerably faster and more accurate at even lower sampling densities compared to the different beam-propagation-methods...
December 26, 2016: Optics Express
Keyvan Jaferzadeh, Samaneh Gholami, Inkyu Moon
In this paper, we evaluate lossless and lossy compression techniques to compress quantitative phase images of red blood cells (RBCs) obtained by an off-axis digital holographic microscopy (DHM). The RBC phase images are numerically reconstructed from their digital holograms and are stored in 16-bit unsigned integer format. In the case of lossless compression, predictive coding of JPEG lossless (JPEG-LS), JPEG2000, and JP3D are evaluated, and compression ratio (CR) and complexity (compression time) are compared against each other...
December 20, 2016: Applied Optics
Carlos Trujillo, Raúl Castañeda, Pablo Piedrahita-Quintero, Jorge Garcia-Sucerquia
An automatic method that fully compensates the quantitative phase measurements in off-axis digital holographic microscopy (DHM) is presented. The two main perturbations of the quantitative phase measurements in off-axis DHM are automatically removed. While the curvature phase flaw introduced by the microscope objective is avoided by the use of an optimized telecentric imaging system for the recording of the holograms, the remaining phase perturbation due to the tilt of the reference wave is removed by the automatic computation of a digital compensating reference wave...
December 20, 2016: Applied Optics
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
Jian Yu, Shenye Liu, Jin Li, Zhiwen Yang, Ming Chen, Luting Guo, Li Yao, Shali Xiao
In this paper, we introduce a new method to calibrate the absolute sensitivity of a soft X-ray streak camera (SXRSC). The calibrations are done in the static mode by using a small laser-produced X-ray source. A calibrated X-ray CCD is used as a secondary standard detector to monitor the X-ray source intensity. In addition, two sets of holographic flat-field grating spectrometers are chosen as the spectral discrimination systems of the SXRSC and the X-ray CCD. The absolute sensitivity of the SXRSC is obtained by comparing the signal counts of the SXRSC to the output counts of the X-ray CCD...
December 2016: Review of Scientific Instruments
Dan Parker, Daniel Lantz
This paper presents a computational model that integrates a dynamically structured holographic memory system into the ACT-R cognitive architecture to explain how linguistic representations are encoded and accessed in memory. ACT-R currently serves as the most precise expression of the moment-by-moment working memory retrievals that support sentence comprehension. The ACT-R model of sentence comprehension is able to capture a range of linguistic phenomena, but there are cases where the model makes the wrong predictions, such as the over-prediction of retrieval interference effects during sentence comprehension...
December 31, 2016: Topics in Cognitive Science
Michael Lawrence Castanares, Vini Gautam, Jack Drury, Hans Bachor, Vincent R Daria
Two-photon imaging using high-speed multi-channel detectors is a promising approach for optical recording of cellular membrane dynamics at multiple sites. A main bottleneck of this technique is the limited number of photons captured within a short exposure time (~1ms). Here, we implement temporal gating to improve the two-photon fluorescence yield from holographically projected multiple foci whilst maintaining a biologically safe incident average power. We observed up to 6x improvement in the signal-to-noise ratio (SNR) in Fluorescein and cultured hippocampal neurons showing evoked calcium transients...
December 1, 2016: Biomedical Optics Express
Vahideh Farzam Rad, Ali-Reza Moradi, Ahmad Darudi, Lobat Tayebi
No abstract text is available yet for this article.
December 1, 2016: Journal of Biomedical Optics
Keyvan Jaferzadeh, Inkyu Moon
No abstract text is available yet for this article.
December 1, 2016: Journal of Biomedical Optics
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