Read by QxMD icon Read

Photonic crystals

Guanhai Li, Brendan P Clarke, Jin-Kyu So, Kevin F MacDonald, Nikolay I Zheludev
Recent advances in the physics and technology of light generation via free-electron proximity and impact interactions with nanostructures (gratings, photonic crystals, nano-undulators, metamaterials and antenna arrays) have enabled the development of nanoscale-resolution techniques for such applications as mapping plasmons, studying nanoparticle structural transformations and characterizing luminescent materials (including time-resolved measurements). Here, we introduce a universal approach allowing generation of light with prescribed wavelength, direction, divergence and topological charge via point-excitation of holographic plasmonic metasurfaces...
December 2, 2016: Nature Communications
G P Loisel, M Wu, W Stolte, C Kruschwitz, P Lake, G S Dunham, J E Bailey, G A Rochau
The Advanced Light Source beamline-9.3.1 x-rays are used to calibrate the rocking curve of bent potassium acid phthalate (KAP) crystals in the 2.3-4.5 keV photon-energy range. Crystals are bent on a cylindrically convex substrate with a radius of curvature ranging from 2 to 9 in. and also including the flat case to observe the effect of bending on the KAP spectrometric properties. As the bending radius increases, the crystal reflectivity converges to the mosaic crystal response. The X-ray Oriented Programs (xop) multi-lamellar model of bent crystals is used to model the rocking curve of these crystals and the calibration data confirm that a single model is adequate to reproduce simultaneously all measured integrated reflectivities and rocking-curve FWHM for multiple radii of curvature in both 1st and 2nd order of diffraction...
November 2016: Review of Scientific Instruments
C Reverdin, A Casner, F Girard, L Lecherbourg, B Loupias, V Tassin, F Philippe
Two x-ray spectrometers have been built for x-ray spectroscopy of laser-produced plasmas on OMEGA at the Laboratory for Laser Energetics (LLE) by Commissariat à l'Energie Atomique et aux énergies alternatives (CEA). The accessible photon energy range is from 1.5 to 20 keV. The first spectrometer, called X-ray CEA Crystal Spectrometer with a Charge-Injection Device (XCCS-CID), records three spectra with three crystals coupled to a time integrated CID camera. The second one, called X-ray CEA Crystal Spectrometer (XCCS) with a framing camera, is time resolved and records four spectra with two crystals on the four frames of a framing camera...
November 2016: Review of Scientific Instruments
G V Brown, P Beiersdorfer, N Hell, E Magee
We have used the EBIT-I electron beam ion trap at the Lawrence Livermore National Laboratory and a duplicate Orion High Resolution X-ray Spectrometer (OHREX) to measure the relative efficiency of a spherically bent quartz (101̄1) crystal (2d = 6.687 Å) and a spherically bent germanium (111) crystal (2d = 6.532 Å). L-shell X-ray photons from highly charged molybdenum ions generated in EBIT-I were simultaneously focussed and Bragg reflected by each crystal, both housed in a single spectrometer, onto a single CCD X-ray detector...
November 2016: Review of Scientific Instruments
L B Fletcher, U Zastrau, E Galtier, E J Gamboa, S Goede, W Schumaker, A Ravasio, M Gauthier, M J MacDonald, Z Chen, E Granados, H J Lee, A Fry, J B Kim, C Roedel, R Mishra, A Pelka, D Kraus, B Barbrel, T Döppner, S H Glenzer
We present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5...
November 2016: Review of Scientific Instruments
M J MacDonald, T Gorkhover, B Bachmann, M Bucher, S Carron, R N Coffee, R P Drake, K R Ferguson, L B Fletcher, E J Gamboa, S H Glenzer, S Göde, S P Hau-Riege, D Kraus, J Krzywinski, A L Levitan, K-H Meiwes-Broer, C P O'Grady, T Osipov, T Pardini, C Peltz, S Skruszewicz, M Swiggers, C Bostedt, T Fennel, T Döppner
Atomic clusters can serve as ideal model systems for exploring ultrafast (∼100 fs) laser-driven ionization dynamics of dense matter on the nanometer scale. Resonant absorption of optical laser pulses enables heating to temperatures on the order of 1 keV at near solid density conditions. To date, direct probing of transient states of such nano-plasmas was limited to coherent x-ray imaging. Here we present the first measurement of spectrally resolved incoherent x-ray scattering from clusters, enabling measurements of transient temperature, densities, and ionization...
November 2016: Review of Scientific Instruments
S G Lee, J W Yoo, Y S Kim, U W Nam, M K Moon
The inconsistency of the first experimental results from the X-ray imaging crystal spectrometer for the Korea Superconducting Tokamak Advanced Research device utilizing a multi-wire proportional counter (MWPC) is clarified after improving the photon-count rate of the data acquisition system for the MWPC and ground loop isolator for the whole spectrometer system. The improved MWPC is successfully applied to pure Ohmic plasmas as well as plasmas with high confinement modes.
November 2016: Review of Scientific Instruments
G Loisel, P Lake, P Gard, G Dunham, L Nielsen-Weber, M Wu, E Norris
At Sandia National Laboratories, the x-ray generator Manson source model 5 was upgraded from 10 to 25 kV. The purpose of the upgrade is to drive higher characteristics photon energies with higher throughput. In this work we present characterization studies for the source size and the x-ray intensity when varying the source voltage for a series of K-, L-, and M-shell lines emitted from Al, Y, and Au elements composing the anode. We used a 2-pinhole camera to measure the source size and an energy dispersive detector to monitor the spectral content and intensity of the x-ray source...
November 2016: Review of Scientific Instruments
Ayman Hamzawy, Dimitar N Grozdanov, Mohamed S Badawi, Fuad A Aliyev, Abouzeid A Thabet, Mahmoud I Abbas, Ivan N Ruskov, Ahmed M El-Khatib, Yuri N Kopatch, Mona M Gouda
Scintillation crystals are usually used for detection of energetic photons at room temperature in high energy and nuclear physics research, non-destructive analysis of materials testing, safeguards, nuclear treaty verification, geological exploration, and medical imaging. Therefore, new designs and construction of radioactive beam facilities are coming on-line with these science brunches. A good number of researchers are investigating the efficiency of the γ-ray detectors to improve the models and techniques used in order to deal with the most pressing problems in physics research today...
November 2016: Review of Scientific Instruments
T Döppner, D Kraus, P Neumayer, B Bachmann, J Emig, R W Falcone, L B Fletcher, M Hardy, D H Kalantar, A L Kritcher, O L Landen, T Ma, A M Saunders, R D Wood
We are developing x-ray Thomson scattering for applications in implosion experiments at the National Ignition Facility. In particular we have designed and fielded MACS, a high-efficiency, gated x-ray spectrometer at 7.5-10 keV [T. Döppner et al., Rev. Sci. Instrum. 85, 11D617 (2014)]. Here we report on two new Bragg crystals based on Highly Oriented Pyrolytic Graphite (HOPG), a flat crystal and a dual-section cylindrically curved crystal. We have performed in situ calibration measurements using a brass foil target, and we used the flat HOPG crystal to measure Mo K-shell emission at 18 keV in 2nd order diffraction...
November 2016: Review of Scientific Instruments
Feng Tian, Hisashi Sumikura, Eiichi Kuramochi, Hideaki Taniyama, Masato Takiguchi, Masaya Notomi
Optomechanical control of on-chip emitters is an important topic related to integrated all-optical circuits. However, there is neither a realization nor a suitable optomechanical structure for this control. The biggest obstacle is that the emission signal can hardly be distinguished from the pump light because of the several orders' power difference. In this study, we designed and experimentally verified an optomechanical oscillation system, in which a lumped mechanical oscillator connected two optically isolated pairs of coupled one-dimensional photonic crystal cavities...
November 28, 2016: Optics Express
Nan Zhang, Georges Humbert, Zhifang Wu, Kaiwei Li, Perry Ping Shum, Nancy Meng Ying Zhang, Ying Cui, Jean-Louis Auguste, Xuan Quyen Dinh, Lei Wei
An in-line optofluidic refractive index (RI) sensing platform is constructed by splicing a side-channel photonic crystal fiber (SC-PCF) with side-polished single mode fibers. A long-period grating (LPG) combined with an intermodal interference between LP<sub>01</sub> and LP<sub>11</sub> core modes is used for sensing the RI of the liquid in the side channel. The resonant dip shows a nonlinear wavelength shift with increasing RI over the measured range from 1.3330 to 1.3961. The RI response of this sensing platform for a low RI range of 1...
November 28, 2016: Optics Express
Frédéric Dumur, Stéphane Reculusa, Michal Mruczkiewicz, Mathias Perrin, Laurence Vignau, Sophie Fasquel
Three-dimensional Langmuir-Blodgett films made of silica beads are theoretically and experimentally investigated in order to improve the relatively small efficiency of blue OLEDs. Using films made of 5 layers of beads, we fabricated OLEDs emitting at 476 nm, and measured a gain of around 40% on their external quantum efficiency. An optical model has been developed to accurately handle the fact that the organic emitting layer and the photonic extraction layer are separated by a distance greater than 1000 wavelength...
November 28, 2016: Optics Express
Andriy E Serebryannikov, Evrim Colak, Thore Magath, Ekmel Ozbay
We study single-beam deflection and asymmetry in transmission, two aspects of the same phenomenon that appear in the topologically simple, nonsymmetric, photonic crystal (PhC)-based structures without corrugations at the interfaces. Strong diffractions enabling efficient blazing, i.e., redistribution of the incident wave energy in favor of the desired higher diffraction order(s), can be achieved owing to the defect-like layer(s) embedded in a regular slab of PhC. The main features, together with the peculiarities of the two basic transmission types and relevant coupling and deflection scenarios, are discussed, for one of which a part of the PhC works in the evanescent-wave regime...
December 1, 2016: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Tatiana Kovalevich, Abdoulaye Ndao, Miguel Suarez, Saulius Tumenas, Zigmas Balevicius, Arunas Ramanavicius, Ieva Baleviciute, Markus Häyrinen, Matthieu Roussey, Markku Kuittinen, Thierry Grosjean, Maria-Pilar Bernal
We present an original type of one-dimensional photonic crystal that includes one anisotropic layer made of a lithium niobate thin film. We demonstrate the versatility of such a device sustaining different Bloch surface waves (BSWs), depending on the orientation of the incident wave. By varying the orientation of the illumination of the multilayer, we measured an angle variation of 7° between the BSWs corresponding to the extraordinary and the ordinary index of the lithium niobate thin film. The potential of such a platform opens the way to novel tunable and active planar optics based on the electro- and thermo-optical properties of lithium niobate...
December 1, 2016: Optics Letters
Zun Huang, Evgenii E Narimanov
We propose a method of optical phase retrieval based on the conical refraction imaging in structured media. We show that a multilayered dielectric photonic crystal functioning as a conically refractive flat lens can be used to reconstruct phase information of complex optical signals. Our method enables a single simultaneous measurement of multiple images on the same image plane and allows a rapid stable recovery of the optical phase. The planar geometry of the proposed device is compatible with current nano-fabrication techniques and, therefore, can find broad applications in optical signal processing and imaging...
December 1, 2016: Optics Letters
Pooria Hosseini, Amir Abdolvand, Philip St J Russell
We report a novel scheme for the generation of dense clusters of Raman sidebands. The scheme uses a broadband-guiding hollow-core photonic crystal fiber (HC-PCF) filled with a mixture of H<sub>2</sub>, D<sub>2</sub>, and Xe for efficient interaction between the gas mixture and a green laser pump pulse (532 nm, 1 ns) of only 5 μJ of energy. This results in the generation from noise of more than 135 rovibrational Raman sidebands covering the visible spectral region with an average spacing of only 2...
December 1, 2016: Optics Letters
Peter Girouard, Zhifu Liu, Pice Chen, Young Kyu Jeong, Yongming Tu, Seng-Tiong Ho, Bruce W Wessels
We report a photonic crystal (PhC) optical modulator operating in the optical C band (1530-1565 nm) using barium titanate epitaxial thin films as the electro-optic (EO) medium. The PhC has hexagonal lattice symmetry and an extinction ratio of 9 dB. Due to the slow light enhancement of the EO coefficient near the PhC band edge, the driving electrode can be as short as a one millimeter. We report for the first time, to the best of our knowledge, at microwave frequencies from 10 to 45 GHz the effective EO coefficient and its enhancement through slow light effects...
December 1, 2016: Optics Letters
Chenyang Zhao, Qingchen Yuan, Liang Fang, Xuetao Gan, Jianlin Zhao
We demonstrate a high-performance relative humidity (RH) sensor by coating a photonic crystal (PC) cavity with polyvinyl alcohol (PVA). Because a PC cavity's evanescent field strongly interacts with the coated moisture-sensitive PVA film, the resonant wavelength is modified remarkably under varying RH levels ranging from 30% to 90%. In a PC cavity coated with a 720 nm thick PVA, the sensor exhibits a linear spectrum sensitivity exceeding 129 pm/%RH over 40-90%RH, and the power interrogation presents a high sensitivity as 0...
December 1, 2016: Optics Letters
Seungwoo Jeon, Heungjoon Kim, Bong-Shik Song, Yuki Yamaguchi, Takashi Asano, Susumu Noda
Measurement of optical loss in nanophotonic waveguides is necessary for monitoring the properties of integrated photonic devices. We propose a simple method of measuring the optical loss using integrated nanocavities. It is shown theoretically that weak coupling between the waveguide and cavities leads to a direct estimation of the optical loss by measuring light radiated from the cavities. In addition, we experimentally demonstrate the optical loss in a fabricated photonic crystal waveguide. Our method gives not only a degree of freedom in real-time monitoring of the optical properties of nanophotonic structures, but it also can be used for various waveguide-based applications...
December 1, 2016: Optics Letters
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"