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Optics Express

Yueming Zhou, Min Li, Yang Li, Aihong Tong, Qianguang Li, Peixiang Lu
Recent experiments on strong-field sequential double ionization (SDI) have reported several observations which are regarded as evidence of electron correlation, querying the validity of the standard independent electron approximation for SDI. Here we theoretically study SDI with a classical ensemble model. The experimental results are well reproduced with this model. Back tracing of the ionization process shows that these results are ascribed to the subcycle ionization dynamics of the two electrons, not the evidences of the electron correlation in SDI...
April 3, 2017: Optics Express
Zhili Lin, Xudong Chen, Panfeng Ding, Weibin Qiu, Jixiong Pu
The ponderomotive interaction of high-power laser beams with collisional plasma is modeled in the nonrelativistic regime and is simulated using the powerful finite-difference time-domain (FDTD) method for the first time in literature. The nonlinear and dissipative dielectric constant function of the collisional plasma is deduced that takes the ponderomotive effect into account and is implemented in the discrete framework of FDTD algorithms. Maclaurin series expansion approach is applied for implementing the obtained physical model and the time average of the square of light field is extracted by numerically evaluating an integral identity based on the composite trapezoidal rule for numerical integration...
April 3, 2017: Optics Express
Zheng Yong, Wesley D Sacher, Ying Huang, Jared C Mikkelsen, Yisu Yang, Xianshu Luo, Patrick Dumais, Dominic Goodwill, Hadi Bahrami, Patrick Guo-Qiang Lo, Eric Bernier, Joyce K S Poon
We demonstrate U-shaped silicon PN junctions for energy efficient Mach-Zehnder modulators and ring modulators in the O-band. This type of junction has an improved modulation efficiency compared to existing PN junction geometries, has low losses, and supports high-speed operation. The U-shaped junctions were fabricated in an 8" silicon photonics platform, and they were incorporated in travelling-wave Mach-Zehnder modulators and microring modulators. For the high-bandwidth Mach-Zehnder modulator, the DC V<sub>π</sub>L at -0...
April 3, 2017: Optics Express
Qiankun Gao, Juan Liu, Xinhui Duan, Tao Zhao, Xin Li, Peilin Liu
A compact see-through three-dimensional head-mounted display (3D-HMD) is proposed and investigated in this paper. Two phase holograms are analytically extracted from the object wavefront and uploaded on different zones of the spatial light modulator (SLM). A holographic grating is further used as the frequency filter to couple the separated holograms together for wavefront modulation. The developed preliminary prototype has a simple optical facility and a compact structure (133.8mm × 40.4mm × 35.4mm with a 47...
April 3, 2017: Optics Express
Wonchan Lee, Daeseong Jung, Suho Ryu, Chulmin Joo
We demonstrate single-shot quantitative phase imaging (QPI) in a platform of color-coded LED microscopy (cLEDscope). The light source in a conventional microscope is replaced by a circular LED pattern that is trisected into subregions with equal area, assigned to red, green, and blue colors. Image acquisition with a color image sensor and subsequent computation based on weak object transfer functions allow for the QPI of a transparent specimen. We also provide a correction method for color-leakage, which may be encountered in implementing our method with consumer-grade LEDs and image sensors...
April 3, 2017: Optics Express
G Martin, M Bhuyan, J Troles, C D'Amico, R Stoian, E Le Coarer
Guided optics spectrometers can be essentially classified into two main families: based on Fourier transform or dispersion. In the first case, an interferogram generated inside an optical waveguide and containing the spectral information is sampled using spatially distributed nanodetectors. These scatter quasi-non-perturbingly light into the detector that is in contact with the waveguide, helping to reconstruct the stationary wave. A dedicated FFT processing is needed in order to recover the spectrum with high resolution but limited spectral range...
April 3, 2017: Optics Express
Hyuntai Kim, Haechan An, Jinseob Kim, Seungsu Lee, Kyoungyoon Park, Seungjong Lee, Seungsoo Hong, Luis Alonso Vazquez-Zuniga, Seung-Yeol Lee, Byoungho Lee, Yoonchan Jeong
We propose a fiber-optic-plasmonic hybrid device that is based on a corrugation-assisted metal-coated angled fiber facet (CA-MCAFF) for wavelength-dependent off-axis directional beaming (WODB). The device breaks into two key structures: One is the MCAFF structure, which is a modified Kretschmann configuration implemented onto a fiber platform, thereby being able to generate a unidirectional surface plasmon with dramatically enhanced properties in terms of non-confined diffracted radiation loss and operational bandwidth...
April 3, 2017: Optics Express
Kevin A G Smet, Qiyan Zhai, Ming R Luo, Peter Hanselaer
In a previous paper, 12 corresponding color data sets were derived for 4 neutral illuminants using the long-term memory colours of five familiar objects. The data were used to test several linear (one-step and two-step von Kries, RLAB) and nonlinear (Hunt and Nayatani) chromatic adaptation transforms (CAT). This paper extends that study to a total of 156 corresponding color sets by including 9 more colored illuminants: 2 with low and 2 with high correlated color temperatures as well as 5 representing high chroma adaptive conditions...
April 3, 2017: Optics Express
Seunghyun Jang, Bonghyuk Park, Songcheol Hong
Two ∆Σ-modulated digital radio-over-fiber (DRoF) transmission systems that employ a multi-pulse Manchester encoder are proposed and experimentally evaluated. With a two-step modulation process comprised of ∆Σ modulation and multi-pulse Manchester encoding, a high frequency replica or image of a ∆Σ-digitized analog communication signal can be transmitted without significant power loss. This is achieved by exploiting the spectral characteristics of the modified Manchester code. For comparative analysis, a conventional ∆Σ-modulation-based DRoF system is also evaluated...
April 3, 2017: Optics Express
Shota Kita, Yang Li, Philip Camayd-Muñoz, Orad Reshef, Daryl I Vulis, Robert W Day, Eric Mazur, Marko Lončar
Zero-index metamaterials (ZIMs) offer unprecedented ways to manipulate the flow of light, and are of interest for wide range of applications including optical cloaking, super-coupling, and unconventional phase-matching properties in nonlinear optics. Impedance-matched ZIMs can be obtained through a photonic Dirac-cone (PDC) dispersion induced by an accidental degeneracy of an electric monopole and a transverse magnetic dipole mode at the center of the Brillouin zone. Therefore, PDC is very sensitive to fabrication imperfections...
April 3, 2017: Optics Express
Dian Chen, Qingwen Liu, Zuyuan He
For a distributed fiber-optic vibration sensor (DFVS), the vibration signal extracted from the phase of backscattering has a linear response to the applied vibration, and is more attractive than that from the intensity term. However, the large phase noise at a random weak-fading-point seriously limits the sensor's credibility. In this paper, a novel phase-detection DFVS is developed, which effectively eliminates the weak-fading-point. The relationship between phase noise and the intensity of backscattering is analyzed, and the inner-pulse frequency-division method and rotated-vector-sum method are introduced to effectively suppress phase noise...
April 3, 2017: Optics Express
Jing Han, Hongjun Liu, Nan Huang, Zhaolu Wang
A novel dynamic of stochastic resonance in spatiotemporal chaos is presented, which is based on modulation instability of perturbed partially coherent wave. The noise immunity of chaos can be reinforced through this effect and used to restore the coherent signal information buried in chaotic perturbation. A theoretical model with fluctuations term is derived from the complex Ginzburg-Landau equation via Wigner transform. It shows that through weakening the nonlinear threshold and triggering energy redistribution, the coherent component dominates the instability damped by incoherent component...
April 3, 2017: Optics Express
Xiao Sun, J Stewart Aitchison, Mo Mojahedi
We have experimentally demonstrated a compact polarization beam splitter (PBS) based on the silicon nitride/silicon-on-insulator platform using the recently proposed augmented-low-index-guiding (ALIG) waveguide structure. The two orthogonal polarizations are split in an asymmetric multimode interference (MMI) section, which was 1.6 μm wide and 4.8 μm long. The device works well over the entire C-band wavelength range and has a measured low insertion loss of less than 1 dB. The polarization extinction ratio at the Bar Port is approximately 17 dB and at the Cross Port is approximately 25 dB...
April 3, 2017: Optics Express
Haochi Yu, Ziyi Zhao, Qinbai Qian, Jie Xu, Peng Gou, Yuexin Zou, Jun Cao, Le Yang, Jie Qian, Zhenghua An
Metamaterial based on a metal/insulator/metal (MIM) tri-layer structure provides an agile platform to realize high absorption efficiency for a variety of applications including semiconductor optoelectronic detectors. In this work, we use the finite time domain difference (FDTD) method and coupled mode theory (CMT) to numerically study metal/semiconductor/metal (MSM) structures and discuss their effective absorption for optoelectronic application. We compare MSM structures with a different top metal layer design and find that cross shaped absorber (CSA) and it's complementary cross shaped absorber (CCSA) exhibit different phase diagrams due to a distinctive dependence of radiation loss on geometrical parameters...
April 3, 2017: Optics Express
Tian-Jiao Li, Sai Li, Yuan Yuan, Yu-Dong Liu, Chuan-Long Xu, Yong Shuai, He-Ping Tan
Plenoptic cameras are used for capturing flames in studies of high-temperature phenomena. However, simulations of plenoptic camera models can be used prior to the experiment improve experimental efficiency and reduce cost. In this work, microlens arrays, which are based on the established light field camera model, are optimized into a hexagonal structure with three types of microlenses. With this improved plenoptic camera model, light field imaging of static objects and flame are simulated using the calibrated parameters of the Raytrix camera (R29)...
April 3, 2017: Optics Express
Federico Machado, Vicente Ferrando, Walter D Furlan, Juan A Monsoriu
Fibonacci zone plates are proving to be promising candidates in image forming devices. In this letter we show that the set of Fibonacci zone plates are a particular member of a new family of diffractive lenses which can be designed on the basis of a given m-bonacci sequence. These lenses produce twin axial foci whose separation depends on the m-golden mean. Therefore, with this generalization, bifocal systems can be freely designed under the requirement at particular focal planes. Experimental results support our proposal...
April 3, 2017: Optics Express
Sahar Hosseinzadeh Kassani, Martin Villiger, Néstor Uribe-Patarroyo, Changsu Jun, Reza Khazaeinezhad, Norman Lippok, Brett E Bouma
Improving the axial resolution by providing wider bandwidth wavelength swept lasers remains an important issue for optical frequency domain imaging (OFDI). Here, we demonstrate a wide tuning range, all-fiber wavelength swept laser at a center wavelength of 1250 nm by combining two ring cavities that share a single Fabry-Perot tunable filter. The two cavities contain semiconductor optical amplifiers with central wavelengths of 1190 nm and 1292 nm, respectively. To avoid disturbing interference effects in the overlapping spectral region, we modulated the amplifiers in order to obtain consecutive wavelength sweeps in the two spectral regions...
April 3, 2017: Optics Express
Jingpei Hu, Yu Lin, Xiaonan Zhao, Aijiao Zhu, Chen Xu, Xiaojun Zhu, Peiji Guo, Bing Cao, Chinhua Wang
We propose and demonstrate an all-metal flexible reflective multiband waveplate based on nano-grating structure using high efficient electroplating growing process, which exhibits quarter waveplate at two wavelengths (λ = 465nm and λ = 921nm) and half waveplate at another wavelength (λ = 656nm). Using Finite Difference Time Domain (FDTD) modeling, the phase shift and reflection efficiency are simulated and designed for a variety of geometrical parameters. A fast and cost-effective technique based on conventional interference lithography and nickel electroplating process is demonstrated to fabricate the all-metal, large-area and flexible waveplate...
April 3, 2017: Optics Express
Seang Hor Eang, Kyuman Cho
A new balanced-path homodyne I/Q-interferometer scheme using a specially designed polarizing beam displacer (PBD) is described. The PBD is designed for splitting the s- and p-polarization components of the input beam into two parallel output beams which can be used as two beams of a balanced-path interferometer. The interferometer has a very simple optical arrangement because all of seven optical components used for interfacing two arms of the interferometer into the I/Q-demodulator in the previous schemes are replaced by the single PBD...
April 3, 2017: Optics Express
Changgeng Liu, Damber Thapa, Xincheng Yao
Guidestar hologram based digital adaptive optics (DAO) is one recently emerging active imaging modality. It records each complex distorted line field reflected or scattered from the sample by an off-axis digital hologram, measures the optical aberration from a separate off-axis digital guidestar hologram, and removes the optical aberration from the distorted line fields by numerical processing. In previously demonstrated DAO systems, the optical aberration was directly retrieved from the guidestar hologram by taking its Fourier transform and extracting the phase term...
April 3, 2017: Optics Express
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