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Displaying 32576 - 32600 of 73963
We report the first quantum key distribution (QKD) experiment to enable the creation of secure keys over 42 dB channel loss and 200 km of optical fibre. We used the differential phase shift QKD (DPS-QKD) protocol, implemented with a 10-GHz clock frequency
Michele M. Schantz, Jennifer M. Lynch, John R. Kucklick, Dianne L. Poster, H M. Stapleton, S S. Vander Pol, Stephen A. Wise
House dust originates from both internal and external sources and has been identified as one of the primary sources of lead exposure for children (http://www.epa.gov/lead). House dust is also a repository for pesticides, flame retardants, and other
This paper describes the development of two test systems at NIST aimed at improving the calibration and characterization of Coordinated Universal Time (UTC) synchronized electric power instrumentation. Reference to UTC is used to meet the need for precise
Mark J. Rivard, Wayne Butler, Larry A. DeWerd, Saiful M. Huq, Geoffrey S. Ibbott, Christopher Melhus, Michael G. Mitch, Ravinder Nath, J Williamson
Since publication of the 2004 update to the American Association of Physicists in Medicine (AAPM) Task Group No. 43 Report (AAPM TG-43U1), several new low-energy photon-emitting brachytherapy sources have become available. Many of these sources have
Kevin G. Brady, Frederic J. de Vaulx, Randolph Elmquist
For several years now, NIST has been a leader in the development and use of Information Technology to process calibration information. Beginning in 1996, researchers designed and developed a calibration database, the NIST Information System to Support
The influence of plastic deformation on the elastic properties that determine the magnitude of springback following forming was investigated using dynamic modulus analysis. For this study, the elastic modulus of TRIP 700 steel was measured continuously at
Mingming M. Feng, N. A. Brilliant, Steven T. Cundiff, Richard Mirin, Kevin L. Silverman
We report a two-section mode-locked quantum dot laser with an emission wavelength that is bistable with respect to applied bias on the saturable absorber region. The two stable lasing wavelengths for this device are 1173 nm and 1166 nm with a power
We show that the performance of a 1310-nm quantum key distribution (QKD) system with an up-conversion detector pumped at 1550 nm is comparable with or better than that of current 1550-nm QKD systems with 1310-nm pump detectors. The nonlinearly induced dark
Electrical characterization of alkanethiol self-assembled monolayers (SAMs) has been performed using a nanometer-scale device structure. Temperature-variable current-voltage measurement is carried out to distinguish between different conduction mechanisms
Leonard M. Hanssen, Claus Cagran, A Prokhorov, Sergey Mekhontsev, V B. Khromchenko
NIST has developed a new facility for the characterization of the infrared spectral emissivity of samples between ambient and 1000 C. For accurate measurement of the sample surface temperatures above 300 C, the system employs a high temperature
In this work we present a preliminary study for the determination of the uncertainty on the frequency in the time measurement. The first part of this paper is dedicated to the theoretical study of the frequency uncertainty applying the law of the
David A. Howe, Archita Hati, Craig Nelson, Jennifer A. Taylor, Neil Ashby
Vibration causes mechanical distortions in fiber-optic transmission lines that induce time (phase) fluctuations. RF systems are increasingly using optical fibers in various ways and must occasionally operate in environments with acoustic and structure-born
An experimental analysis of frequency transfer uncertainty is carried out. In situations where more than one transfer techniques are available a first difference statistic is used to determine the type and level of the transfer noise for transfer methods
Kai Hudek, Archita Hati, W Zhou, David A. Howe, Craig W. Nelson
Optoelectronic oscillators (OEO), utilizing the low loss nature of optical links, can generate oscillations with very high Q values. The long delay line used in the oscillator can, however, support many modes of oscillation. Mode spacing is inversely
V Shah, Svenja A. Knappe, Leo W. Hollberg, John E. Kitching
We demonstrate a simple setup for observing very high contrast coherent population trapping resonances in rubidium-87. The high contrast is achieved by eliminating the DC-light background through polarization and spectral filtering.
Tara M. Fortier, Neil Ashby, James C. Bergquist, Marie Delaney, Scott A. Diddams, Thomas P. Heavner, Leo W. Hollberg, Wayne M. Itano, Steven R. Jefferts, K Kim, Windell Oskay, Thomas E. Parker, Jon H. Shirley, Jason Stalnaker, Filippo Levi, Luca Lorini
We report tests of Local Position Invariance (LPI) and constancy of fundamental constants from measurements of the frequency ratio of the 282-nm 199Hg + optical clock transition to the ground-state hyperfine splitting in 133Cs. Analysis of the frequency
We report the measurement of increased noise cross-correlation between stokes and anti-stokes beams created in cascaded four-wave mixing processes with dual pump wavelengths, when two-photon light is efficiently created at the middle frequency. This method
Optoelectronic oscillators (OEO) are unique compared to radio-frequency (RF) oscillators in that they do not fundamentally require a RF gain element in order to satisfy the amplitude threshold condition for oscillation. All the energy required for
Craig W. Nelson, Archita Hati, David A. Howe, W Zhou
Optoelectronic oscillators (OEO) are unique compared to radio-frequency (RF) oscillators in that they do not fundamentally require a RF gain element in order to satisfy the amplitude threshold condition for oscillation. All the energy required for
We show that a single-Cooper-pair transistor (SCPT) electrometer emits narrow-band microwave radiation when biased in its sub-gap region. Photo-activation of quasiparticle tunneling in a nearby SCPT is used to spectroscopically detect this radiation, in a
Neil Ashby, David A. Howe, Jennifer A. Taylor, Archita Hati, Craig W. Nelson
We derive expressions for the group velocities of transverse electric and transverse magnetic electromagnetic waves in a stretched single-mode fiber. Stretching can occur either as a result of temperature changes of the spool on which the fiber is wound