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https://www.readbyqxmd.com/read/28227716/heart-activity-monitoring-using-3d-hologram-based-on-smartphone
#1
Tharoeun Thap, Heewon Chung, Jinseok Lee, Tharoeun Thap, Heewon Chung, Jinseok Lee, Tharoeun Thap, Jinseok Lee, Heewon Chung
In this paper, we used smartphone to obtained pulsatile signal from a fingertip by illuminating the skin tissue using flashlight and with an on-board camera to record the change of the light intensity reflected from the tissue. The pulsatile signal is produced by analyzing average green component values of the frames taken by the camera and the heart rate is estimated in real time by detecting the pulse peaks. Based on each instant obtained heartbeat, we design a heart animation that beats according to each interval of the heartbeat...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28198854/two-photon-polymerization-of-microstructures-by-a-non-diffraction-multifoci-pattern-generated-from-a-superposed-bessel-beam
#2
Liang Yang, Dongdong Qian, Chen Xin, Zhijiang Hu, Shengyun Ji, Dong Wu, Yanlei Hu, Jiawen Li, Wenhao Huang, Jiaru Chu
In this Letter, superposed Bessel beams (SBBs) are realized by alternatively imprinting holograms of opposite-order Bessel beams along the radial direction on a spatial light modulator. The propagation invariance and non-rotation properties of SBBs are theoretically predicted and experimentally demonstrated. The focusing property of SBBs with a high numerical aperture (NA) objective is investigated with the Debye vectorial diffraction theory. Near the focal plane, a circularly distributed multiple foci pattern is achieved...
February 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28198842/refractive-index-and-gain-grating-in-nd-yvo-sub-4-sub-application-to-speckle-vibrometry-and-photoacoustic-detection
#3
Baptiste Jayet, Jean-Pierre Huignard, Francois Ramaz
Probing local displacements on a scattering surface can be achieved using an adaptive interferometer. The photorefractive-crystal-based interferometer is popular, but alternatives exist such as an adaptive gain interferometer. Such setups take advantage of the nonlinear phenomena in laser media. Because of the gain saturation, it is possible to write a gain hologram and a refractive index hologram to achieve an adaptive interferometer with a linear response. In addition, laser-media-based setups have a fast response time (≤100  μs), which makes them interesting for applications such as detection of photoacoustic waves in living biological samples...
February 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28181514/new-2d-diffraction-model-and-its-applications-to-terahertz-parallel-plate-waveguide-power-splitters
#4
Fan Zhang, Kaijun Song, Yong Fan
A two-dimensional (2D) diffraction model for the calculation of the diffraction field in 2D space and its applications to terahertz parallel-plate waveguide power splitters are proposed in this paper. Compared with the Huygens-Fresnel principle in three-dimensional (3D) space, the proposed model provides an approximate analytical expression to calculate the diffraction field in 2D space. The diffraction filed is regarded as the superposition integral in 2D space. The calculated results obtained from the proposed diffraction model agree well with the ones by software HFSS based on the element method (FEM)...
February 9, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28158100/image-multiplexing-and-encryption-using-the-nonnegative-matrix-factorization-method-adopting-digital-holography
#5
Hsuan T Chang, J-W Shui, K-P Lin
In this paper, a joint multiple-image encryption and multiplexing system, which utilizes both the nonnegative matrix factorization (NMF) scheme and digital holography, is proposed. A number of images are transformed into noise-like digital holograms, which are then decomposed into a defined number of basis images and a corresponding weighting matrix using the NMF scheme. The determined basis images are similar to the digital holograms and appear as noise-like patterns, which are then stored as encrypted data and serve as the lock in an encryption system...
February 1, 2017: Applied Optics
https://www.readbyqxmd.com/read/28158083/holographic-microinformation-hiding
#6
Tomoyoshi Shimobaba, Yutaka Endo, Ryuji Hirayama, Daisuke Hiyama, Yuki Nagahama, Satoki Hasegawa, Marie Sano, Takayuki Takahashi, Takashi Kakue, Minoru Oikawa, Tomoyoshi Ito
We propose a holographic microinformation hiding scheme in which the embedding information to be embedded is small and imperceptible to the human eyes. This scheme converts the embedding information into a complex amplitude via scaled diffraction. The complex amplitude of the reduced embedding information is added to the complex amplitude of the host image, followed by conversion to a hologram. The reduced embedded information is inconspicuous from the hologram during the reconstruction process; however, the reduction leads to the degradation of the embedded image quality...
February 1, 2017: Applied Optics
https://www.readbyqxmd.com/read/28158016/digital-super-resolution-holographic-data-storage-based-on-hermitian-symmetry-for-achieving-high-areal-density
#7
Teruyoshi Nobukawa, Takanori Nomura
Digital super-resolution holographic data storage based on Hermitian symmetry is proposed to store digital data in a tiny area of a medium. In general, reducing a recording area with an aperture leads to the improvement in the storage capacity of holographic data storage. Conventional holographic data storage systems however have a limitation in reducing a recording area. This limitation is called a Nyquist size. Unlike the conventional systems, our proposed system can overcome the limitation with the help of a digital holographic technique and digital signal processing...
January 23, 2017: Optics Express
https://www.readbyqxmd.com/read/28157974/photonic-jet-reconstruction-for-particle-refractive-index-measurement-by-digital-in-line-holography
#8
Matthias P L Sentis, Fabrice R A Onofri, Fabrice Lamadie
A new and computationally efficient approach is proposed for determining the refractive index of spherical and transparent particles, in addition to their size and 3D position, using digital in-line holography. The method is based on the localization of the maximum intensity position of the photonic jet with respect to the particle center retrieved from the back propagation of recorded holograms. Rigorous electromagnetic calculations and experimental results demonstrate that for liquid-liquid systems and droplets with a radius > 30µm, a refractive index measurement with a resolution inferior to 4 × 10<sup>-3</sup> is achievable, revealing a significant potential for the use of this method to investigate multiphase flows...
January 23, 2017: Optics Express
https://www.readbyqxmd.com/read/28146507/high-resolution-parallel-phase-shifting-digital-holography-using-a-low-resolution-phase-shifting-array-device-based-on-image-inpainting
#9
Shuming Jiao, Wenbin Zou
Parallel phase-shifting digital holography can record high-quality holograms efficiently from fast-moving objects in a dynamic scene. However, a phase-shifting array device with a cell size identical to image sensors is required, which imposes difficulty in practice. This Letter proposes a novel scheme to employ a low-resolution phase-shifting array device to achieve high-resolution parallel phase-shifting digital holography, based on image inpainting performed on incomplete holograms. The experimental results validate the effectiveness of the proposed scheme...
February 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28146490/all-optical-coaxial-framing-photography-using-parallel-coherence-shutters
#10
Chen Guanghua, Li Jianfeng, Peng Qixian, Liu Shouxian, Liu Jun
An all-optical framing camera has been developed to obtain serial images of high temporal and spatial resolution with identical spatial benchmark, identical temporal benchmark, and identical chromatic benchmark in a single shot. A train of laser probe pulses with identical wavelength coaxially illuminate the target and form sequentially timed images by means of parallel coherence shutters. A coherence shutter only selects one of the probe pulses to form a nonmultiplexing hologram. The other probe pulses superpose incoherently on the hologram as the background...
February 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28146482/single-shot-incoherent-digital-holography-using-a-dual-focusing-lens-with-diffraction-gratings
#11
Xiangyu Quan, Osamu Matoba, Yasuhiro Awatsuji
A new optical configuration of incoherent digital holography is presented to improve the quality of reconstructed images when the random polarization state of incoherent light is used. The proposed system improves the signal-to-noise ratio of the holograms by suppressing the unmodulated terms of a spatial light modulator. To generate the self-interference of a quasi-incoherent point-like source, we use a dual-focusing lens with diffraction gratings. The preliminary experimental results confirm the validity of the proposed method by reconstructing two point-like sources generated by a LED light source...
February 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28117346/holographic-image-generation-with-a-thin-film-resonance-caused-by-chalcogenide-phase-change-material
#12
Seung-Yeol Lee, Yong-Hae Kim, Seong-M Cho, Gi Heon Kim, Tae-Youb Kim, Hojun Ryu, Han Na Kim, Han Byeol Kang, Chi-Young Hwang, Chi-Sun Hwang
The development of digital holography is anticipated for the viewing of 3D images by reconstructing both the amplitude and phase information of the object. Compared to analog holograms written by a laser interference, digital hologram technology has the potential to realize a moving 3D image using a spatial light modulator. However, to ensure a high-resolution 3D image with a large viewing angle, the hologram panel requires a near-wavelength scale pixel pitch with a sufficient large numbers of pixels. In this manuscript, we demonstrate a digital hologram panel based on a chalcogenide phase-change material (PCM) which has a pixel pitch of 1 μm and a panel size of 1...
January 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28081079/simple-and-fast-spectral-domain-algorithm-for-quantitative-phase-imaging-of-living-cells-with-digital-holographic-microscopy
#13
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
https://www.readbyqxmd.com/read/28074963/ultrahigh-capacity-dynamic-holographic-displays-via-anisotropic-nanoholes
#14
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
https://www.readbyqxmd.com/read/28069769/normal-modes-and-mode-transformation-of-pure-electron-vortex-beams
#15
G Thirunavukkarasu, M Mousley, M Babiker, J Yuan
Electron vortex beams constitute the first class of matter vortex beams which are currently routinely produced in the laboratory. Here, we briefly review the progress of this nascent field and put forward a natural quantum basis set which we show is suitable for the description of electron vortex beams. The normal modes are truncated Bessel beams (TBBs) defined in the aperture plane or the Fourier transform of the transverse structure of the TBBs (FT-TBBs) in the focal plane of a lens with the said aperture...
February 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/28059333/cavity-enhanced-eigenmode-and-angular-hybrid-multiplexing-in-holographic-data-storage-systems
#16
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
https://www.readbyqxmd.com/read/28059313/speckleless-holographic-display-by-complex-modulation-based-on-double-phase-method
#17
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
https://www.readbyqxmd.com/read/28059271/lossless-and-lossy-compression-of-quantitative-phase-images-of-red-blood-cells-obtained-by-digital-holographic-imaging
#18
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
https://www.readbyqxmd.com/read/28059249/automatic-full-compensation-of-quantitative-phase-imaging-in-off-axis-digital-holographic-microscopy
#19
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
https://www.readbyqxmd.com/read/28059198/asymmetric-gaussian-optical-vortex
#20
Victor V Kotlyar, Alexey A Kovalev, Alexey P Porfirev
We theoretically study a Gaussian optical beam with an embedded off-axis optical vortex. We also experimentally generate such an asymmetric Gaussian optical vortex by using an off-axis spiral phase plate. It is shown that depending on the shift distance the laser beam has the form of a crescent, which is rotated upon propagation. An analytical expression is obtained for the orbital angular momentum of such a beam, which appears to be fractional. When the shift increases, the greater the number of spirality of the phase plate or the "fork" hologram, the slower the momentum decreases...
January 1, 2017: Optics Letters
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