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Diego Hincapie, Daniel Velasquez, Jorge Garcia-Sucerquia
In this Letter, we present a method for chromatic compensation in numerical reconstruction of digitally recorded holograms based on Fresnel-Bluestein propagation. The proposed technique is applied to correct the chromatic aberration that arises in the reconstruction of RGB holograms of both millimeter- and micrometer-sized objects. The results show the feasibility of this strategy to remove the wavelength dependence of the size of the numerically propagated wavefields.
December 15, 2017: Optics Letters
Dingnan Deng, Weijuan Qu, Wenqi He, Yu Wu, Xiaoli Liu, Xiang Peng
We present a simple and effective compensation method for the off-axis tilt in common-path digital holographic microscopy (CPDHM) by introducing a rotating operation on the hologram. The proposed method mainly requires a digital reference hologram (DRH), which is a rotated version of the original one; it is assumed to be easy to obtain by rotating the specimen's hologram 180°. In this way, the off-axis tilt could be removed by subtracting the retrieved phase of DRH from the retrieved phase of the original hologram, but without any complex spectrum centering judgment, fitting procedures, or prior knowledge of the system...
December 15, 2017: Optics Letters
D Cody, I Naydenova
The suitability of holographic structures fabricated in zeolite nanoparticle-polymer composite materials for gas sensing applications has been investigated. Theoretical modeling of the sensor response (i.e., change in hologram readout due to a change in refractive index modulation or thickness as a result of gas adsorption) of different sensor designs was carried out using Raman-Nath theory and Kogelnik's coupled wave theory. The influence of a range of parameters on the sensor response of holographically recorded surface and volume photonic grating structures has been studied, namely the phase difference between the diffracted and probe beam introduced by the grating, grating geometry, thickness, spatial frequency, reconstruction wavelength, and zeolite nanoparticle refractive index...
December 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Marvin Dion Alim, David J Glugla, Sudheendran Mavila, Chen Wang, Philip D Nystrom, Amy C Sullivan, Robert McLeod, Christopher N Bowman
Holographic photopolymers capable of high refractive index modulation (Δn) on the order of 10-2 are integral for the fabrication of functional holographic optical elements that are useful in a myriad of optical applications. In particular, to address the deficiency of suitable high refractive index writing monomers for use in two-stage holographic formulations, here we report a novel high refractive index writing monomer, 1,3-bis(phenylthio)-2-propyl acrylate (BPTPA), simultaneously possessing enhanced solubility in a low refractive index (n = 1...
December 13, 2017: ACS Applied Materials & Interfaces
Zhenyu Zhao, Chen Xie, DanDan Ni, Yuquan Zhang, Yanfeng Li, Francois Courvoisier, Minglie Hu
We propose a simple technique to scale the abruptly autofocusing beams in the direct space by introducing a scaling factor in the phase. Analytical formulas are deduced based on optical caustics, explicitly revealing how the scaling factor controls location, peak intensity, and size of the focal spot. We demonstrate that the multiplication of a scaling factor on the phase is equivalent to the axial-scaling transformation under the paraxial approximation. Further numerical and experimental results confirm theoretical predictions...
November 27, 2017: Optics Express
Alessio Lugnan, Joni Dambre, Peter Bienstman
The computational power required to classify cell holograms is a major limit to the throughput of label-free cell sorting based on digital holographic microscopy. In this work, a simple integrated photonic stage comprising a collection of silica pillar scatterers is proposed as an effective nonlinear mixing interface between the light scattered by a cell and an image sensor. The light processing provided by the photonic stage allows for the use of a simple linear classifier implemented in the electric domain and applied on a limited number of pixels...
November 27, 2017: Optics Express
Hak Gu Kim, Yong Man Ro
In this paper, we propose a new ultrafast layer based CGH calculation that exploits the sparsity of hologram fringe pattern in 3-D object layer. Specifically, we devise a sparse template holographic fringe pattern. The holographic fringe pattern on a depth layer can be rapidly calculated by adding the sparse template holographic fringe patterns at each object point position. Since the size of sparse template holographic fringe pattern is much smaller than that of the CGH plane, the computational load can be significantly reduced...
November 27, 2017: Optics Express
Peilin Liu, Juan Liu, Xin Li, Qiankun Gao, Tao Zhao, Xinhui Duan
A non-iterative design and precise fabrication method of diffractive optical elements (DOEs) on multiple freeform surfaces is proposed and investigated in this paper. Complex amplitude modulation (CAM) technology is applied to design complicated DOEs. The wave-front for desired DOEs fabrication is interfered with a plane wave and then be encoded to a pure phase hologram. Simulations for different DOEs (binary and gray scales) on freeform surfaces are performed and the relative errors are 0.56% and 0.78%, respectively...
November 27, 2017: Optics Express
Seok-Beom Ko, Jae-Hyeung Park
We propose a method that eliminates speckle artifact in the reconstruction of triangular mesh based computer generated holograms. The proposed method generates a number of holograms with different sets of interleaved plane carrier waves. The generated holograms are displayed sequentially with time-multiplexing, achieving speckle-free reconstruction without sacrificing the viewing angle or depth of focus. The proposed method is verified experimentally using viewing-window type holographic display setup. The experimental results indicate that the proposed method can achieve speckle-free reconstruction with smaller number of the time-multiplexing than conventional temporal speckle averaging techniques...
November 27, 2017: Optics Express
Changlin Zheng, Timothy C Petersen, Holm Kirmse, Wolfgang Neumann, Michael J Morgan, Joanne Etheridge
We demonstrate experimentally an efficient electron axicon lens using a magnetic vortex. We show that naturally occurring magnetic vortices with circular magnetic moment distributions in a soft-magnetic thin film create conical phase shifts for fast electrons. Such radially symmetric linear phase ramps are equivalent to ideal light optical axicons. We apply this lens to generate efficient nondiffracting electron Bessel beams, which we observe experimentally in through-focus Lorentz images as well as in propagated off-axis electron holograms...
October 27, 2017: Physical Review Letters
Vahid Abbasian, Ehsan A Akhlaghi, Mohammad A Charsooghi, Maasoomeh Bazzar, Ali-Reza Moradi
The aim of this paper is to introduce digital holographic microscopy (DHM) as a non-contact, inexpensive, and non-abrasive method for 3D surface characterization of polymeric nanocomposites. A common-path and vibration-immune Mirau system with a microsphere-assisted arrangement is utilized to increase the lateral resolution of the images. The characterization is performed through the measurement of roughness parameters of the surfaces, which are derived from the recorded holograms. Pure poly(triazole-amide-imide) (PTAI) and PTAI nanocomposite reinforeced with surface modified TiO2 nanoparticles (MN-TiO2) are used and compared...
November 28, 2017: Ultramicroscopy
Peng Xia, Qinghua Wang, Shien Ri, Hiroshi Tsuda
A calibrated phase-shifting digital holography system based on the sampling Moiré technique is proposed. Two synchronized cameras are used in this system. One is to record the conventional holograms that include the object information, and the other is to record the interference fringes to analyze phase-shifting errors. An algorithm for improving the quality of the reconstructed images is proposed. In this Letter, the effectiveness of the proposed system and algorithm is demonstrated in four-step phase-shifting digital holography...
December 1, 2017: Optics Letters
Yongxiong Ren, Cong Liu, Kai Pang, Jiapeng Zhao, Yinwen Cao, Guodong Xie, Long Li, Peicheng Liao, Zhe Zhao, Moshe Tur, Robert W Boyd, Alan E Willner
We experimentally demonstrate spatial multiplexing of an orbital angular momentum (OAM)-encoded quantum channel and a classical Gaussian beam with a different wavelength and orthogonal polarization. Data rates as large as 100 MHz are achieved by encoding on two different OAM states by employing a combination of independently modulated laser diodes and helical phase holograms. The influence of OAM mode spacing, encoding bandwidth, and interference from the co-propagating Gaussian beam on registered photon count rates and quantum bit error rates is investigated...
December 1, 2017: Optics Letters
Haidong Zhang, Xiaokun Wang, Donglin Xue, Xuejun Zhang
Large convex aspheric optical elements have been widely applied in advanced optical systems, which have presented a challenging metrology problem. Conventional testing methods cannot satisfy the demand gradually with the change of definition of "large." A modified method is proposed in this paper, which utilizes a relatively small computer-generated hologram and an illumination lens with certain feasibility to measure the large convex aspherics. Two example systems are designed to demonstrate the applicability, and also, the sensitivity of this configuration is analyzed, which proves the accuracy of the configuration can be better than 6 nm with careful alignment and calibration of the illumination lens in advance...
December 1, 2017: Applied Optics
Kai Melde, Eunjin Choi, Zhiguang Wu, Stefano Palagi, Tian Qiu, Peer Fischer
Acoustic assembly promises a route toward rapid parallel fabrication of whole objects directly from solution. This study reports the contact-free and maskless assembly, and fixing of silicone particles into arbitrary 2D shapes using ultrasound fields. Ultrasound passes through an acoustic hologram to form a target image. The particles assemble from a suspension along lines of high pressure in the image due to acoustic radiation forces and are then fixed (crosslinked) in a UV-triggered reaction. For this, the particles are loaded with a photoinitiator by solvent-induced swelling...
December 4, 2017: Advanced Materials
Junji Kobashi, Hiroyuki Yoshida, Masanori Ozaki
Recent advances in nanofabrication techniques are opening new frontiers in holographic devices, with the capability to integrate various optical functions in a single device. However, while most efficient holograms are achieved in reflection-mode configurations, they are in general opaque because of the reflective substrate that must be used, and therefore, have limited applicability. Here, we present a semi-transparent, reflective computer-generated hologram that is circularly-polarization dependent, and reconstructs different wavefronts when viewed from different sides...
November 28, 2017: Scientific Reports
Manuel Bedrossian, Casey Barr, Chris A Lindensmith, Kenneth Nealson, Jay L Nadeau
Accurately detecting and counting sparse bacterial samples has many applications in the food, beverage, and pharmaceutical processing industries, in medical diagnostics, and for life detection by robotic missions to other planets and moons of the solar system. Currently, sparse bacterial samples are counted by culture plating or epifluorescence microscopy. Culture plates require long incubation times (days to weeks), and epifluorescence microscopy requires extensive staining and concentration of the sample...
November 1, 2017: Journal of Visualized Experiments: JoVE
Sk Abdul Amin, Nilanjan Adhikari, Sonam Bhargava, Shovanlal Gayen, Tarun Jha
Integrins [Formula: see text] and [Formula: see text] are important targets to treat different inflammatory diseases, such as multiple sclerosis, inflammatory bowel diseases, rheumatoid arthritis, atherosclerosis, and asthma. Despite being valuable targets, only a few work has been reported to date regarding molecular modeling studies on these integrins. Not only that, none of these reports addressed the selectivity issue between integrins [Formula: see text] and [Formula: see text]. Therefore, a major challenge regarding the design and discovery of selective integrin antagonists remains...
November 17, 2017: Molecular Diversity
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 toward the center. Shifting the phase of the plasmon waves as a function of space gives complete control over the location of the focus...
November 21, 2017: Nano Letters
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
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