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Chiu-Yen Wang, Yu-Chen Hong, Zong-Jie Ko, Ya-Wen Su, Jin-Hua Huang
In this study, defect-free zinc blende GaAs nanowires on Si (111) by molecular beam epitaxy (MBE) growth are systematically studied through Au-assisted vapor-liquid-solid (VLS) method. The morphology, density, and crystal structure of GaAs nanowires were investigated as a function of substrate temperature, growth time, and As/Ga flux ratio during MBE growth, as well as the thickness, annealing time, and annealing temperature of Au film using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), cathodoluminescence (CL), and Raman spectroscopy...
December 2017: Nanoscale Research Letters
Jitendra K Pradhan, S Anantha Ramakrishna, Bharathi Rajeswaran, Arun M Umarji, Venu Gopal Achanta, Amit K Agarwal, Amitava Ghosh
A metamaterial consisting of an array of gold micro-disks, separated from a ground plane of indium tin oxide (ITO) by a thin film of vanadium dioxide (VO<sub>2</sub>), behaves as a perfect absorber at infrared (IR) frequencies at room temperature. This metamaterial, which is transparent to visible light, can be switched to a highly reflecting state for IR light by heating the metamaterial to temperatures larger than the metal-insulator phase transition temperature 68°C of VO<sub>2</sub>...
April 17, 2017: Optics Express
Guoqiang Xu, Haochun Zhang, Yan Jin, Sen Li, Yao Li
We propose a fundamental latent function of control heat transfer and heat flux density vectors at random positions on thermal materials by applying transformation optics. The expressions for heat flux bending are obtained, and the factors influencing them are investigated in both 2D and 3D cloaking schemes. Under certain conditions, more than one degree of freedom of heat flux bending exists corresponding to the temperature gradients of the 3D domain. The heat flux path can be controlled in random space based on the geometrical azimuths, radial positions, and thermal conductivity ratios of the selected materials...
April 17, 2017: Optics Express
Yan Zhang, Yinsheng Xu, Chenyang You, Dong Xu, Junzhou Tang, Peiqing Zhang, Shixun Dai
Chemical stoichiometric Ge-As-S glasses were prepared, and their thermal properties, refractive index (n), optical bandgap, Raman gain, and femtosecond laser damage were examined. Results revealed that the n and density (ρ) of the glasses decreased as Ge concentration increased, whereas the bandgap and glass transition temperature (Tg) increased. The Raman gain coefficients (g<sub>R</sub>) of the samples were calculated on the basis of spontaneous Raman scattering spectra. g<sub>R</sub> decreased from 2...
April 17, 2017: Optics Express
Xian Zhou, Yutang Dai, Joseph Muna Karanja, Fufei Liu, Minghong Yang
Hydrogen gas sensing properties of Pt-WO<sub>3</sub> films on spiral microstructured fiber Bragg grating (FBG) has been demonstrated. Pt-WO<sub>3</sub> film was prepared by hydrothermal method. The spiral microsturctured FBG was fabricated using femtosecond laser. Spiral microstructure FBG hydrogen sensor can detect hydrogen concentration from 0.02% H<sub>2</sub> to 4% H<sub>2</sub> at room temperature, and the response time is shortened from a few minutes to 10~30 s...
April 17, 2017: Optics Express
Lu Yin, Mingjian Yan, Zhigang Han, Hailin Wang, Hua Shen, Rihong Zhu
We present the segmented corrosion method that uses hydrofluoric acid to etch the fiber of a fiber laser for removing high-power cladding light to improve stripping uniformity and power handling capability. For theoretical guidelines, we propose a simulation model of etched-fiber stripping to evaluate the relationship between the etched-fiber parameters and cladding light attenuation and to analyze the stripping uniformity achieved with segmented corrosion. A two-segment etched fiber is fabricated with cladding light attenuation of 19...
April 17, 2017: Optics Express
Simone Ferrari, Vadim Kovalyuk, Wladislaw Hartmann, Andreas Vetter, Oliver Kahl, Changhyoup Lee, Alexander Korneev, Carsten Rockstuhl, Gregory Gol'tsman, Wolfram Pernice
We investigate how the bias current affects the hot-spot relaxation dynamics in niobium nitride. We use for this purpose a near-infrared pump-probe technique on a waveguide-integrated superconducting nanowire single-photon detector driven in the two-photon regime. We observe a strong increase in the picosecond relaxation time for higher bias currents. A minimum relaxation time of (22 ± 1) ps is obtained when applying a bias current of 50% of the switching current at 1.7 K bath temperature. We also propose a practical approach to accurately estimate the photon detection regimes based on the reconstruction of the measured detector tomography at different bias currents and for different illumination conditions...
April 17, 2017: Optics Express
D H Slichter, V B Verma, D Leibfried, R P Mirin, S W Nam, D J Wineland
We demonstrate superconducting nanowire single photon detectors with 76 ± 4% system detection efficiency at a wavelength of 315 nm and an operating temperature of 3.2 K, with a background count rate below 1 count per second at saturated detection efficiency. We propose integrating these detectors into planar surface electrode radio-frequency Paul traps for use in trapped ion quantum information processing. We operate detectors integrated into test ion trap structures at 3.8 K both with and without typical radio-frequency trapping electric fields...
April 17, 2017: Optics Express
Santosh Kumar, Haoquan Fan, Harald Kübler, Akbar J Jahangiri, James P Shaffer
Rydberg atom-based electrometry enables traceable electric field measurements with high sensitivity over a large frequency range, from gigahertz to terahertz. Such measurements are particularly useful for the calibration of radio frequency and terahertz devices, as well as other applications like near field imaging of electric fields. We utilize frequency modulated spectroscopy with active control of residual amplitude modulation to improve the signal to noise ratio of the optical readout of Rydberg atom-based radio frequency electrometry...
April 17, 2017: Optics Express
Wei Quan, Kai Wei, Hairong Li
We demonstrate a novel method of measuring magnetic field based on the transient signal of the K-Rb-<sup>21</sup>Ne co-magnetometer operating in nuclear spin magnetization self-compensation magnetic field regime. The operation condition for self-compensation magnetic field by nuclear spin magnetization of <sup>21</sup>Ne in steady state is presented. We characterize the dynamics of the coupled spin ensembles by a set of Bloch equations, and formulate the expression of transient output signal...
April 17, 2017: Optics Express
Marit Ulset Nordsveen, Chi Kwong Tang, Jarle Gran
We demonstrate the use of a dual-mode detector for determining the internal quantum deficiency of a silicon photodiode without the use of an external reference. This is achieved by combining two different principles for measuring optical power in one device, where the photodiode is used as absorber for both thermal and photon detection. Thermal detection is obtained by the same principle as for an electrical substitution radiometer (ESR), with a type A measurement uncertainty of 0.34 % in unstabilized room temperature...
April 17, 2017: Optics Express
Zaifa Yang, Denghui Xu, Jiayue Sun
A series of Ba<sub>3</sub>Lu(PO<sub>4</sub>)<sub>3</sub>:Sm<sup>3+</sup> phosphors were prepared by traditional high temperature solid-state reaction methods. The site-preferred occupancy of Sm<sup>3+</sup> in Ba<sub>3</sub>Lu(PO<sub>4</sub>)<sub>3</sub> and the luminescence properties of Ba<sub>3</sub>Lu(PO<sub>4</sub>)<sub>3</sub>:Sm<sup>3+</sup> were studied combined with X-ray diffraction, photoluminescence excitation (PLE) spectra, and emission (PL) spectra as well as temperature-dependent PL and decay curves...
April 17, 2017: Optics Express
Xiaofan Zhao, Zining Yang, Weihong Hua, Hongyan Wang, Xiaojun Xu
Although the diode pumped alkali laser (DPAL) works in a three-level scheme, higher energy-state excitation and ionization processes exist during operation, which may lead to deleterious effects on laser performance. In this paper, we report the ionization degree measurement in the gain medium of an operational hydrocarbon-free Rb DPAL by using the optogalvanic method. The results show that, at the pulsed mode with a duration of ~1 ms, a maximal ionization degree of ~0.06% is obtained at a pump power of 140 W...
April 17, 2017: Optics Express
Yongfeng Wu, Yundong Zhang, Jing Wu, Ping Yuan
We experimentally demonstrate transverse load and strain sensing based on a fiber optic Fabry-Perot interferometer (FPI) with special air cavity, which was created by fusion splicing single mode fiber (SMF), hollow core fiber (HCF) and several electrical arc discharges. The cavity height of this structure is higher than the cladding diameter of SMF so that it can sense transverse load with high sensitivity. The transverse load sensitivity of this air cavity FPI sensor is 1.31 nm∕N and about 5 times more sensitive compared to the current fiber tip interferometer (0...
April 17, 2017: Optics Express
J Ma, H H Yu, X Jiang, D S Jiang
A high-performance temperature sensor based on mode-coupling principle is proposed using a selectively filled, solid-core photonic crystal fiber with a central air-bore. The fibers are fabricated using the "stack-and-draw" method, with a micro scale central bore deliberately kept during the drawing procedure. The addition of the central air-bore enhances the mode-coupling efficiency between the fundamental core mode and modes in the high-index liquid-filled holes in the fiber cladding, therefore, the fiber can be used for a novel sensing architecture, when cladding holes are selectively filled with temperature sensitive liquids...
April 17, 2017: Optics Express
Wei Chen, Shiqiang Luo, Zunyuan Wan, Xiyuan Feng, Xinke Liu, Zhubing He
As it already made huge effect in the commercialization of silicon and other photovoltaics, interface engineering is dispensable in the current and future evolution of hybrid perovskite solar cells (PSCs) techniques. In order to solve carriers' recombination and detention at the cathode side of planar PSCs, in this work, Ruthenium acetylacetonate (RuAcac) was successfully adopted as a reliable and stable cathode interfacial layer (CIL) to improve the inverted planar PSCs. The power conversion efficiency of the optimal devices was enhanced from 12...
April 17, 2017: Optics Express
Heba Mohammed Ibrahim Abdallah, Abdelsamed Ibrahim Elshamy, Abd El-Nasser Gaber El Gendy, Ahmed Mohamed Abd El-Gawad, Elsayed Abouelfotowh Omer, Marinella De Leo, Luisa Pistelli
Cressa cretica is a widely grown halophytic plant traditionally used for the treatment of different ailments. Previous investigations reported its biological activity on a wide spectrum of diseases. In this study, in vivo antinociceptive, anti-inflammatory, and antipyretic activities of C. cretica aqueous extract whole plant were evaluated. In addition, the total polyphenol content, the total flavonoid content, and the chemical characterization of the extract were performed. C. cretica showed writhing inhibition in acetic acid-induced peripheral nociception of 43 and 48 % at doses of 50 and 100 mg/kg, respectively...
April 24, 2017: Planta Medica
Di Tian, Yuanyuan Zhang, Yizhen Zhou, Yujing Mu, Junfeng Liu, Chenglong Zhang, Pengfei Liu
N2O and NO emissions from a winter wheat-summer maize rotation field with five different treatments in the North China Plain (NCP) were comparably investigated from 8 October 2014 to 11 October 2015. Compared with the treatments with only flood or drip irrigation, evident emission peaks of N2O and NO from the fertilization treatments with flood irrigation (A-Flood) and with drip fertigation (A-Drip) were observed after each fertilization event, whereas their emissions from the fertilization treatments with nitrification inhibitors under drip fertigation (A+DCD-Drip and A+Nitrapyrin-Drip) were greatly suppressed...
April 21, 2017: Science of the Total Environment
Yongming Zhang, Qi Zhao, Wenyi Zhang, Shanshan Li, Gongbo Chen, Zhihai Han, Yuming Guo
BACKGROUND: It is well documented that suboptimal ambient temperature is associated with cardiovascular and respiratory diseases. However, no study has examined the relation between temperature and dog bites. OBJECTIVES: To study the association between ambient temperature and daily hospital emergency department visits due to dog bites (EDVDBs) in Beijing, China; and to explore whether the temperature-EDVDB association varies by sex and age. METHODS: Daily EDVDBs were collected from a hospital appointed for dog bites in Beijing during 2012-2014...
April 21, 2017: Science of the Total Environment
Shafiullah Khan, Wang Runguo, Kamran Tahir, Zhang Jichuan, Liqun Zhang
A simple, green method is described for the synthesis of Gold (Au) nanoparticles (NPs) using Cotoneaster horizontalis extract as a phyto-reducer and capping agent with superior photo inhibition activity against Pseudomonas aeruginosa. Different from the other methods used elevated temperatures for nanoparticles synthesis, the novelty of our method lies in its energy saving process and fast synthesis rates (~5min for AuNPs), and its potential to tune the nanoparticles size and afterward their catalytic activity...
April 13, 2017: Journal of Photochemistry and Photobiology. B, Biology
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