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Bo Wang, Baogang Quan, Jingwen He, Zhenwei Xie, Xinke Wang, Junjie Li, Qiang Kan, Yan Zhang
A wavelength de-multiplexing metasurface hologram composed of subwavelength metallic antennas is designed and demonstrated experimentally in the terahertz (THz) regime. Different character patterns are generated at the separated working frequencies 0.50 THz and 0.63 THz which determine a narrow frequency bandwidth of 130 GHz. The two working frequencies are around the central resonance frequency of the antennas where antennas behave strong wavefront modulation. Each antenna is fully utilized to control the wavefront of the metasurface at different frequencies by an optimization algorithm...
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
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
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
Vinicius G Maltarollo, Sheila C Araujo, Gustavo H G Trossini, Kathia M Honorio
AIM: Type 2 diabetes mellitus and metabolic syndrome are two diseases related to disorders of lipid and carbohydrate metabolism and insulin resistance. Peroxisome proliferator-activated receptors (PPARs) are a class of nuclear receptors that control the metabolism of lipids/carbohydrates and are considered targets for both diseases. PPAR affinity and selectivity are critical points to design drug candidates with appropriated pharmacodynamic/kinetic profiles. MATERIALS & METHODS: Hologram quantitative structure-activity relationships studies were conducted, as well molecular docking and molecular interaction field calculations, in order to explain affinity and selectivity of selected compounds...
October 2016: Future Medicinal Chemistry
Davood Khodadad, Alok Kumar Singh, Giancarlo Pedrini, Mikael Sjödahl
The objective of this paper is to describe a full-field deformation measurement method based on 3D speckle displacements. The deformation is evaluated from the slope of the speckle displacement function that connects the different reconstruction planes. For our experiment, a symmetrical arrangement with four illuminations parallel to the planes (x,z) and (y,z) was used. Four sets of speckle patterns were sequentially recorded by illuminating an object from the four directions, respectively. A single camera is used to record the holograms before and after deformations...
September 20, 2016: Applied Optics
Elsa S R Fonseca, Paulo T Fiadeiro, Manuela Pereira, António Pinheiro
Numerical reconstruction of digital holograms relies on a precise knowledge of the original object position. However, there are a number of relevant applications where this parameter is not known in advance and an efficient autofocusing method is required. This paper addresses the problem of finding optimal focusing methods for use in reconstruction of digital holograms of macroscopic amplitude and phase objects, using digital in-line phase-shifting holography in transmission mode. Fifteen autofocus measures, including spatial-, spectral-, and sparsity-based methods, were evaluated for both synthetic and experimental holograms...
September 20, 2016: Applied Optics
Jing Wang, Yunlong Sheng
A new approach for designing the binary computer-generated hologram (CGH) of a very large number of pixels is proposed. Diffraction of the CGH apertures is computed by the analytical Abbe transform and by considering the aperture edges as the basic diffracting elements. The computation cost is independent of the CGH size. The arbitrary-shaped polygonal apertures in the CGH consist of quadrilateral apertures, which are designed by assigning the binary phases using the parallel genetic algorithm with a local search, followed by optimizing the locations of the co-vertices with a direct search...
September 20, 2016: Applied Optics
Sihao Ding, Siyang Cao, Yuan F Zheng, Robert L Ewing
We propose an approach to produce computer generated holograms (CGHs) from image pairs of a real-world scene. The ratio of the three-dimensional (3D) physical size of the object is computed from the image pair to provide the correct depth cue. A multilayer wavefront recording plane method completed with a two-stage occlusion culling process is carried out for wave propagation. Multiple holograms can be generated by propagating the wave toward the desired angles, to cover the circular views that are wider than the viewing angle restricted by the wavelength and pitch size of a single hologram...
September 20, 2016: Applied Optics
Alexander J Macfaden, Stephen J Kindness, Timothy D Wilkinson
We propose a synchronous implementation of compressive imaging. This method is mathematically equivalent to prevailing sequential methods, but uses a static holographic optical element to create a spatially distributed spot array from which the image can be reconstructed with an instantaneous measurement. We present the holographic design requirements and demonstrate experimentally that the linear algebra of compressed imaging can be implemented with this technique. We believe this technique can be integrated with optical metasurfaces, which will allow the development of new compressive sensing methods...
September 10, 2016: Applied Optics
Jianglei Di, Ying Li, Min Xie, Jiwei Zhang, Chaojie Ma, Teli Xi, Enpu Li, Jianlin Zhao
A dual-wavelength common-path digital holographic microscopy based on a single parallel glass plate is presented to achieve quantitative phase imaging, which combines the dual-wavelength technique with lateral shearing interferometry. Two illumination laser beams with different wavelengths (λ<sub>1</sub>=532  nm and λ<sub>2</sub>=632.8  nm) are reflected by the front and back surfaces of the parallel glass plate to create the lateral shear and form the digital hologram, and then the hologram is reconstructed to obtain the phase distribution with a synthetic wavelength Λ=3339...
September 10, 2016: Applied Optics
Hyeokjun Byeon, Jaehyun Lee, Junsang Doh, Sang Joon Lee
Volumetric observation is essential for understanding the details of complex biological phenomena. In this study, a bright-field microscope, which provides information on a specific 2D plane, and a holographic microscope, which provides information spread over 3D volumes, are integrated to acquire two complementary images simultaneously. The developed system was successfully applied to capture distinct T-cell adhesion dynamics on inflamed endothelial layers, including capture, rolling, crawling, transendothelial migration, and subendothelial migration...
2016: Scientific Reports
Vadim Migunov, Christian Dwyer, Chris B Boothroyd, Giulio Pozzi, Rafal E Dunin-Borkowski
The technique of double exposure electron holography, which is based on the superposition of two off-axis electron holograms, was originally introduced before the availability of digital image processing to allow differences between electron-optical phases encoded in two electron holograms to be visualised directly without the need for holographic reconstruction. Here, we review the original method and show how it can now be extended to permit quantitative studies of phase shifts that oscillate in time. We begin with a description of the theory of off-axis electron hologram formation for a time-dependent electron wave that results from the excitation of a specimen using an external stimulus with a square, sinusoidal, triangular or other temporal dependence...
August 18, 2016: Ultramicroscopy
Jun Dong, Chao Jiang, Shuhai Jia
We propose a multi-angle interferometry method for digital holographic metrology. In an application of three-dimensional (3D) reconstruction, the hologram corresponding to a different illumination angle is recorded as the illumination angle with a single wavelength tilted at regular intervals by an electronically controlled rotating stage. A Fourier-transform-based axial depth scanning algorithm formed by the reconstructed phase is used to obtain the height point by point over the whole field of view. Hence, the 3D reconstruction can be obtained effectively; even the object has large depth discontinuities resulting from the difficulty of the phase unwrapping...
September 15, 2016: Optics Letters
Qiu Wang, Xueqian Zhang, Yuehong Xu, Jianqiang Gu, Yanfeng Li, Zhen Tian, Ranjan Singh, Shuang Zhang, Jiaguang Han, Weili Zhang
As a revolutionary three-dimensional imaging technique, holography has attracted wide attention for its ability to photographically record a light field. However, traditional phase-only or amplitude-only modulation holograms have limited image quality and resolution to reappear both amplitude and phase information required of the objects. Recent advances in metasurfaces have shown tremendous opportunities for using a planar design of artificial meta-atoms to shape the wave front of light by optimal control of both its phase and amplitude...
2016: Scientific Reports
Van Vuong Hoang, Youngji Cho, Jung Ho Yoo, Soon-Ku Hong, Yong Ho Choi, Sungha Choi, Wooduck Jung, Chang Kyu Jeong, Jun-Mo Yang
Recent years have seen a great deal of progress in the development of transmission electron microscopy-based techniques for strain measurement. Dark-field electron holography (DFEH) is a new technique offering configuration of the off-axis principle. Using this technique with medium magnification (Holo-M), we carried out strain measurements in nanoscale-triangular SiGe/(001) Si with (004), (2(-)20) and ((-)111) diffraction spots. The reconstruction of holograms and interpretation of strain maps in term of strain precision were discussed and the strain distributions in the SiGe/(001) Si patterns were visualized...
September 8, 2016: Microscopy
Rafael Paez-Lopez, Ulises Ruiz, Victor Arrizon, Ruben Ramos-Garcia
We discuss a simple method to generate a configurable annular vortex beam (AVB) with the maximum possible peak intensity, employing a phase hologram whose transmittance is the phase of a Bessel beam. Due to its maximum intensity, the AVB provides the optimal density of the orbital angular moment. Another attribute of the generated AVB is the relatively high invariance of the intensity profile when the topological charge is changed. We demonstrate the advantages and flexibility of these AVBs for optical trapping applications...
September 1, 2016: Optics Letters
Yiying Zhang, Guoguo Kang, Jinliang Zang, Jue Wang, Ying Liu, Xiaodi Tan, Tsutomu Shimura, Kazuo Kuroda
We report on the inverse polarizing effect (IPE) of an elliptical-polarization recorded hologram at a large recording angle. The IPE is a polarizing phenomenon in which the reconstructed signal switches the major and minor axes and keeps the original polarization, direction compared, to that of the signal wave. In reviewing the case of a linear-polarization and circular-polarization recorded hologram, we found that the IPE is a unique phenomenon for elliptical polarization. The IPE was observed at the cross angle of 38° experimentally, and was theoretically explained using tensor theory to remove paraxial limitation...
September 1, 2016: Optics Letters
Jérôme Dohet-Eraly, Catherine Yourassowsky, Frank Dubois
The knowledge of the complex amplitude of optical fields, that is, both quantitative phase and intensity, enables numeric reconstruction along the optical axis. Nonetheless, a criterion is required for autofocusing. This Letter presents a robust and rapid refocusing criterion suitable for color interferometric digital holographic microscopy, and, more generally, for applications where complex amplitude is known for at least two different wavelengths. This criterion uses the phase in the Fourier domain, which is compared among wavelengths...
September 1, 2016: Optics Letters
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