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Optics Express

Stefan Heist, Chen Zhang, Karl Reichwald, Peter Kühmstedt, Gunther Notni, Andreas Tünnermann
Measuring the shape (coordinates x, y, z ) and spectral characteristics (wavelength-dependent reflectance R (λi)) of macroscopic objects as a function of time (t) is of great interest in areas such as medical imaging, precision agriculture, or optical sorting. Here, we present an approach that allows to determine all these quantities with high resolution and accuracy, enabling measurement in five dimensions. We call this approach 5D hyperspectral imaging. We describe the design and implementation of a 5D sensor operating in the visible to near-infrared spectral range, which provides excellent spatial and spectral resolution, great depth accuracy, and high frame rates...
September 3, 2018: Optics Express
A I Shugurov, E A Mashkovich, S B Bodrov, M Tani, M I Bakunov
We report efficient high-resolution electro-optic sampling detection of broadband terahertz radiation by measuring direct intensity modulation of a femtosecond fiber laser beam induced by terahertz field in a 1-cm thick GaAs crystal.
September 3, 2018: Optics Express
Yue Tian, Guanhua Li, Hua Zhang, Linlin Xu, Anxin Jiao, Feng Chen, Ming Chen
The abuse of antibiotics in animal husbandry has been regarded as a daunting public health risk, facilitating the emergence and spread of resistant pathogens to humans. Herein, bimetallic Au@Ag core-shell nanorods (NRs) with precise, controllable Ag shell-thickness (2.1~14.1 nm) were fabricated and developed for ultralow detection of levofloxacin molecules using surface enhanced Raman scattering spectroscopy (SERS). We found that the Au@Ag NRs with 7.3 nm Ag shell-thickness provided maximized SERS activity in comparison with other as-prepared nanosubstrates in this paper...
September 3, 2018: Optics Express
Guan-Yu Wang, Tao Li, Qing Ai, Fu-Guo Deng
Usually, the hyperparallel quantum computation can speed up quantum computing, reduce the quantum resource consumed largely, resist to noise, and simplify the storage of quantum information. Here, we present the first scheme for the self-error-corrected hyperparallel photonic quantum computation working with both the polarization and the spatial-mode degrees of freedom of photon systems simultaneously. It can prevent bit-flip errors from happening with an imperfect nonlinear interaction in the nearly realistic condition...
September 3, 2018: Optics Express
Hiroyuki Endo, Mikio Fujiwara, Mitsuo Kitamura, Orie Tsuzuki, Toshiyuki Ito, Ryosuke Shimizu, Masahiro Takeoka, Masahide Sasaki
Free space optical (FSO) communications are enabling high-speed global wireless networks. Thanks to the highly directional nature of laser beam, they also yield a greater security advantage over radio frequency counterparts. When combined with a scheme of secret key agreement (SKA), FSO-SKA can establish at high speed a symmetric secret key which cannot be decrypted even by unbounded computer resources. Although there have been many theoretical studies on SKA, experimental investigations have been quite lacking, especially on quantifying eavesdropping risks and secret key rates in realistic environment...
September 3, 2018: Optics Express
Sheng Zhu, Shankar Pidishety, Yutong Feng, Soonki Hong, Jeff Demas, Raghuraman Sidharthan, Seongwoo Yoo, Siddharth Ramachandran, Balaji Srinivasan, Johan Nilsson
We report the first demonstration of Raman amplification in a fiber of a single Bessel-like higher order mode using a multimode pump source. We amplify the LP08 -mode with a 559-µm2 effective mode area at a signal wavelength of 1115 nm in a pure-silica-core step-index fiber. A maximum of 18 dB average power gain is achieved in a 9-m long gain fiber, with output pulse energy of 115 µJ. The Raman pump source comprises a pulsed 1060 nm ytterbium-doped fiber amplifier with V-value ~30, which is matched to the Raman gain fiber...
September 3, 2018: Optics Express
Simon Schwarz, Stefan Rung, Cemal Esen, Ralf Hellmann
We report on the fabrication of an axicon by applying a two-step manufacturing process including a 1030 nm femtosecond and a 10.6 µm CO2 laser. First, the pre-defined axicon geometry is generated by high-precision femtosecond layer-by-layer ablation. In order to meet high surface quality requirements, inevitable stipulated for optical use, the surface of the thus structured axicon is smoothened by a subsequent CO2 laser polishing process. The finalized axicon fulfills optical quality as the surface roughness Ra is significantly reduced from 0...
September 3, 2018: Optics Express
Lei Huang, Mourad Idir, Chao Zuo, Tianyi Wang, Kashmira Tayabaly, Erich Lippmann
In this paper, a two-dimensional stitching interferometry system using two tiltmeters is proposed. During the scanning and the measurement, one tiltmeter stays with the interferometer and the other one is attached to the translation stage where the surface under test is placed. The differences of the x- and y-tilt readings between these two tiltmeters are recorded as the relative tilt between interferometer and surface under test. The relative tilt in both x- and y-directions are used to correct the surface tip/tilt of each subset, and then the piston is adjusted to get the final stitching surface map...
September 3, 2018: Optics Express
Anja Bregar, Mitja Štimulak, Miha Ravnik
Periodic birefringence is today extensively explored as an interesting route for controlling the flow of light. Distinctly, complex fluids with periodic modulations of birefringence can perform as photonic crystals, with the main examples being cholesteric and blue phases birefringent profiles. Here we demonstrate the characteristics of light propagation in heliconical liquid crystal and demonstrate their tunable optical and photonic properties, specifically as one-dimensional photonic crystals, in the regime of heliconical pitch comparable to the wavelength of light...
September 3, 2018: Optics Express
Xiang Yin, Lin Chen, Xun Li
Plasmonic metasurfaces have shown great potential to generate Airy plasmons on a metal surface, but the building block of metasurfaces in these works is purposely designed to operate under limited polarization states for the incident light. Here, it is shown that paired nanoslit resonators on a metal surface can provide Airy phase distributions under different polarization incidences. We demonstrate that Airy plasmons can be generated under x-, y-, left-handed circular, and right-handed circular polarization incidences by adjusting the orientation angles of the paired nanoslit resonators...
September 3, 2018: Optics Express
Peng Gao, Junyan Rong, Huangsheng Pu, Tianshuai Liu, Wenli Zhang, Xiaofeng Zhang, Hongbing Lu
Cone beam X-ray luminescence computed tomography (CB-XLCT) has been proposed as a promising hybrid imaging technique. Though it has the advantage of fast imaging, the inverse problem of CB-XLCT is seriously ill-conditioned, making the image quality quite poor, especially for imaging multi-targets. To achieve fast imaging of multi-targets, which is essential for in vivo applications, a truncated singular value decomposition (TSVD) based sparse view CB-XLCT reconstruction method is proposed in this study. With the weight matrix of the CB-XLCT system being converted to orthogonal by TSVD, the compressed sensing (CS) based L1 -norm method could be applied for fast reconstruction from fewer projection views...
September 3, 2018: Optics Express
Jicheng Wang, Chunyu Lu, Zheng-Da Hu, Chen Chen, Liang Pan, Weiqiang Ding
We study the plasmonic properties of face-to-face phosphorene pairs, including their optical constraints and optical gradient forces. The symmetric and anti-symmetric plasmonic modes occur due to the strong anisotropic dispersion of phosphorene. Compared with the anti-symmetric mode, the symmetric mode has a stronger optical constraint and much larger gradient force. Especially, the optical constraint of the symmetric mode can even reach as high as 96% when the two phosphorene layers are along the armchair and zigzag direction respectively...
September 3, 2018: Optics Express
Menghao Huang, Simin Li, Min Xue, Lei Zhao, Shilong Pan
Optical single-ring resonance inherently generates Lorentzian-shape magnitude and group-delay responses, leading to critical performance limitation in photonics, cavity quantum electrodynamics, cavity optomechanics, and atomic and optical physics. Here, we propose a new type of microresonator that stimulates flat-top resonance in a single-ring cavity. By manipulating the fast and slow light effects in the microresonator, the flat-top group delay can be tuned with an ignorable magnitude variation. In addition, the bandpass response can be switched to a notch, which can enable function-reconfigurable photonic integrated circuits (PICs) without a physical change in the architecture...
September 3, 2018: Optics Express
Peixiong Zhang, Nan Chen, Siqi Zhu, Zhen Li, Zhenqiang Chen, Yi Zheng, Jin Yu
Bi/Ta double doped Gd0.1 Y0.9 AlO3 (Bi/Ta:GYAP) near-infrared (NIR) laser crystal was successfully grown. The codoping of Ta5+ was demonstrated to effectively enhance the NIR fluorescence emission in Bi/Ta:GYAP crystal for the first time. The introduced Ta5+ ion can induce the change of valence states from Bi3+ to Bi+ based on the charge compensation mechanism, bringing about the enhanced NIR fluorescence emission. The three NIR fluorescence emission peaks centering at 1005, 1195, and 1280 nm were ascribed to three different Bi+ active centers in Bi/Ta:GYAP crystal...
September 3, 2018: Optics Express
Vladlen Shvedov, Konrad Cyprych, M Yadira Salazar-Romero, Yana Izdebskaya, Wieslaw Krolikowski
We study nonlinear propagation of light in colloidal suspension of metallic nanoparticles, in the regime of particles surface plasmon resonance. We show that the propagation exhibits features typical for purely defocusing media and the observed spatial confinement is not a real self-trapping, as for solitons, but rather than is caused by the phase modulation of the beam via nonlocal defocusing nonlinearity. We also show that the light-induced refractive index change in the suspension leads to stabilization of structured light beams...
September 3, 2018: Optics Express
Xiangshuai Meng, Jiaji Wu, Zhensen Wu, Tan Qu, Lin Yang
In this paper, a dual-band dual-polarized reflectarray for generating dual beams with respect to carrying two different orbital angular momentum (OAM) topological charges operating in the C-band in horizontal polarization and in the X-band in vertical polarization is proposed, with two separate horns performing on the two proposed bands as the feeding. The proposed reflectarray consists of two band reflective element cells operating in two orthogonal directions. Owing to the two composing elements orthogonally interleaved on the reflectarray surface, the corresponding phase compensation performance in one band can be slightly affected by the elemental resonance in another band; thus, the degree of the coupling between the elements with different-band operations can be neglected, resulting in fairly independent phase compensation...
September 3, 2018: Optics Express
Jeongho Ha, Abdoulaye Ndao, Liyi Hsu, Jun-Hee Park, Boubacar Kante
Conventional optical components have been proposed to realize high-quality line focusing with uniform intensity distribution such as cylindrical lenses, segmented wedge-arrays, or a combination of prisms and spherical mirrors. Numerous factors such as the manufacturing tolerances or the need for precise alignment of conventional lenses cause wave front aberrations that impact the performance of optical systems. These aforementioned limitations affect the uniformity of the intensity distribution and the intercept factor of lenses...
September 3, 2018: Optics Express
Andres Forrer, Markus Rösch, Matthew Singleton, Mattias Beck, Jérôme Faist, Giacomo Scalari
Quantum cascade lasers are proving to be instrumental in the development of compact frequency comb sources at mid-infrared and terahertz frequencies. Here we demonstrate a heterogeneous terahertz quantum cascade laser with two active regions spaced exactly by one octave. Both active regions are based on a four-quantum well laser design and they emit a combined 3 mW peak power at 15 K in pulsed mode. The two central frequencies are 2.3 THz (bandwidth 300 GHz) and 4.6 THz (bandwidth 270 GHz). The structure is engineered in a way that allows simultaneous operation of the two active regions in the comb regime, serving as a double comb source as well as a test bench structure for all waveguide internal self-referencing techniques...
September 3, 2018: Optics Express
Guogang Zhang, Zhiqiang Zhang, Youdang Xu, Jianhua Wang
Arc plasmas are common and important phenomena, which have been widely used in scientific research and industrial fields. It is a non-intrusive way to understand the dynamic characteristics of arc plasma by measuring magnetic field distribution and applying inverse method. Aiming to investigate the motion characteristics of arc plasma, a high-speed magneto-optical imaging system was developed, which mainly consists of a laser-driven light source, achromatic collimator, beam expander, polarized beam splitter, analyzer and high-speed camera...
September 3, 2018: Optics Express
Aimin Yan, Xizeng Wu, Hong Liu
In most of grating x-ray interferometry one needs an absorbing grating as the analyzer to measure high-resolution interference fringes. Dual phase grating interferometry is a technique to get rid of the absorbing grating for radiation dose reduction. The authors present a quantitative theory of dual grating x-ray interferometry. The theory elucidates the fringe formation mechanism. The derived formulas of fringe period and fringe visibility provide useful tools for design optimization of dual phase grating interferometers...
September 3, 2018: Optics Express
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