6,350 research outputs found
Time-Multiplexed Measurements of Nonclassical Light at Telecom Wavelengths
We report the experimental reconstruction of the statistical properties of an
ultrafast pulsed type-II parametric down conversion source in a periodically
poled KTP waveguide at telecom wavelengths, with almost perfect photon-number
correlations. We used a photon-number-resolving time-multiplexed detector based
on a fiber-optical setup and a pair of avalanche photodiodes. By resorting to a
germane data-pattern tomography, we assess the properties of the nonclassical
light states states with unprecedented precision.Comment: 4.5 pages, 5 color figues. Comments welcome
Efficient algorithm for optimizing data pattern tomography
We give a detailed account of an efficient search algorithm for the data
pattern tomography proposed by J. Rehacek, D. Mogilevtsev, and Z. Hradil [Phys.
Rev. Lett.~\textbf{105}, 010402 (2010)], where the quantum state of a system is
reconstructed without a priori knowledge about the measuring setup. The method
is especially suited for experiments involving complex detectors, which are
difficult to calibrate and characterize. We illustrate the approach with the
case study of the homodyne detection of a nonclassical photon state.Comment: 5 pages, 5 eps-color figure
High-speed Schottky photodiode on semi-insulating GaAs
A high-speed GaAs photodiode has been fabricated on a GaAs semi-insulating substrate. The photodiode has an active area of 8 μm × 15 μm and a bandwidth in excess of 9 GHz. This Schottky photodiodes is suitable for monolithic integration with other optoelectronic components
On the line shape of the electrically detected ferromagnetic resonance
This work reviews and examines two particular issues related with the new
technique of electrical detection of ferromagnetic resonance (FMR). This
powerful technique has been broadly applied for studying magnetization and spin
dynamics over the past few years. The first issue is the relation and
distinction between different mechanisms that give rise to a photovoltage via
FMR in composite magnetic structures, and the second is the proper analysis of
the FMR line shape, which remains the "Achilles heel" in interpreting
experimental results, especially for either studying the spin pumping effect or
quantifying the spin Hall angles via the electrically detected FMR.Comment: 14 pages, 9 figure
Evaluation of a Commercial Enzyme Linked Immunosorbent Assay (ELISA) for the Determination of the Neurotoxin BMAA in Surface Waters
The neurotoxin ß-N-methylamino-L-alanine (BMAA) is suspected to play a role in Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis. Because BMAA seems to be produced by cyanobacteria, surface waters are screened for BMAA. However, reliable analysis of BMAA requires specialized and expensive equipment. In 2012, a commercial enzyme-linked immunosorbent assay (ELISA) for determination of BMAA in surface waters was released. This kit could enable fast and relatively cheap screening of surface waters for BMAA. The objective of this study was to determine whether the BMAA ELISA kit was suitable for the determination of BMAA concentrations in surface waters. We hypothesised that the recovery of spiked samples was close to 100% and that the results of unspiked sample analysis were comparable between ELISA and liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. However, we found that recovery was higher than 100% in most spiked samples, highest determined recovery was over 400%. Furthermore, the ELISA gave a positive signal for nearly each tested sample while no BMAA could be detected by LC-MS/MS. We therefore conclude that in its current state, the kit is not suitable for screening surface waters for BMAA
Construction and Expected Performance of the Hadron Blind Detector for the PHENIX Experiment at RHIC
A new Hadron Blind Detector (HBD) for electron identification in high density
hadron environment has been installed in the PHENIX detector at RHIC in the
fall of 2006. The HBD will identify low momentum electron-positron pairs to
reduce the combinatorial background in the mass spectrum, mainly
in the low-mass region below 1 GeV/c. The HBD is a windowless
proximity-focusing Cherenkov detector with a radiator length of 50 cm, a CsI
photocathode and three layers of Gas Electron Multipliers (GEM). The HBD uses
pure CF as a radiator and a detector gas. Construction details and the
expected performance of the detector are described.Comment: QM2006 proceedings, 4 pages 3 figure
Three-dimensional imaging of vortex structure in a ferroelectric nanoparticle driven by an electric field
AbstractTopological defects of spontaneous polarization are extensively studied as templates for unique physical phenomena and in the design of reconfigurable electronic devices. Experimental investigations of the complex topologies of polarization have been limited to surface phenomena, which has restricted the probing of the dynamic volumetric domain morphology in operando. Here, we utilize Bragg coherent diffractive imaging of a single BaTiO3 nanoparticle in a composite polymer/ferroelectric capacitor to study the behavior of a three-dimensional vortex formed due to competing interactions involving ferroelectric domains. Our investigation of the structural phase transitions under the influence of an external electric field shows a mobile vortex core exhibiting a reversible hysteretic transformation path. We also study the toroidal moment of the vortex under the action of the field. Our results open avenues for the study of the structure and evolution of polar vortices and other topological structures in operando in functional materials under cross field configurations.</jats:p
A Hadron Blind Detector for the PHENIX Experiment
A novel Hadron Blind Detector (HBD) has been developed for an upgrade of the
PHENIX experiment at RHIC. The HBD will allow a precise measurement of
electron-positron pairs from the decay of the light vector mesons and the
low-mass pair continuum in heavy-ion collisions. The detector consists of a 50
cm long radiator filled with pure CF4 and directly coupled in a windowless
configuration to a triple Gas Electron Multiplier (GEM) detector with a CsI
photocathode evaporated on the top face of the first GEM foil.Comment: 4 pages, 3 figures, Quark Matter 2005 conference proceeding
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