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Displaying 36701 - 36725 of 74164

High resolution spectroscopy with a femtosecond laser frequency comb

July 25, 2005
Author(s)
Vladislav Gerginov, C E. Tanner, Scott A. Diddams, A Bartels, Leo W. Hollberg
The output of a mode-locked femtosecond-laser is usd for high resolution spectroscopy of Cs in an atomic beam. The laser is referenced directly to the stable RF signal from the NIST time-scale. By changing the laser's rate, the Cs D 1 and D 2 transitions

Optical frequency metrology using spectrally tailored continuum from a nonlinear fiber grating

July 25, 2005
Author(s)
Kyoungsik Kim, Brian R. Washburn, Christopher W. Oates, Leo W. Hollberg, Nathan R. Newbury, Scott A. Diddams, P. S. Westbrook, Jeffrey W. Nicholson, K Feder
We report the significant enhancement (-24 dB) of the optical beat note between a 657-nm CW laser and the tailored continuum generated with a nonlinear fiber Bragg grating. The same continuum is used to stabilize the offset frequency of a Cr:forsterite

Optical frequency metrology using spectrally tailored continuum from a nonlinear fiber grating

July 25, 2005
Author(s)
Kyoungsik Kim, Brian R. Washburn, C. W. Oates, Leo W. Hollberg, Nathan R. Newbury, Scott Diddams, Paul S. Westbrook, Jeffrey W. Nicholson, K Feder
We report the significant enhancement (24 dB) of the optical beat note between a 657-nm CW laser and the tailored continuum generated with a nonlinear fiber Bragg grating. The same continuum is used to stabilize the offset frequency of a Cr:forsterite

Optical Microwave Frequency Stability: Some Constraints

July 25, 2005
Author(s)
Leo W. Hollberg, Scott A. Diddams, A Bartels, John J. McFerran, Eugene N. Ivanov, G Wilpers, Christopher W. Oates
Optical frequency references achieve the best frequency stability of any oscillators by taking advantage of high Q = υ 0/{Δ}υ optical resonances. These systems are beginning to run into fundamental and technical limitations which are discussed.

Spectroscopy of a single Al + ion via coupling to Be +

July 25, 2005
Author(s)
Till P. Rosenband, Piet Schmidt, Jeroen Koelemeij, Wayne M. Itano, Yohei Kobayashi, Tara M. Fortier, Scott A. Diddams, James C. Bergquist, David J. Wineland
We perform precision spectroscopy on 27Al + with the aid of a 9Be + ion. Using sympathetic cooling and quantum state transfer, we efficiently interrogate the 1S 0 – 3P 1 and 1S 0 – 3P 0 transitions.

Laboratory X-Ray Imaging of High-Intensity Discharge Lamps

July 22, 2005
Author(s)
John J. Curry, B Lafitte
We describe a laboratory-scale system for x-ray absorption imaging of the Hg vapor distribution in high-intensity discharge plasmas. This system utilizes commercially-available equipment, including an x-ray tube source. We analyze the sensitivity of the

Measurement of the Quadrupole Moment in the Mercury Ion Optical Clock

July 21, 2005
Author(s)
Windell Oskay, Wayne M. Itano, James C. Bergquist
We report a measurement of the 199Hg + 5d 96 s 2 2 d5/2 electric quadrupole moment and discuss its implications for the accruacy of an optical clock based upon 2S 1/2(F=0)<-> 2 d5/2(F=2) transition at 282 nm.

Interferometric Thickness Calibration of 300mm Silicon Wafers

July 20, 2005
Author(s)
Quandou (. Wang, Ulf Griesmann, Robert S. Polvani
The Improved Infrared Interferometer (IR3) at the National Institute of Standards and Technology (NIST) is a phase-measuring interferometer, operating at a wavelength of 1550 nm, which is being developed for measuring the thickness and thickness variation

Direct Measurement of the Counterion Distribution Within Swollen Polyelectrolyte Films

July 19, 2005
Author(s)
Vivek M. Prabhu, B D. Vogt, Wen-Li Wu, Eric K. Lin, Jack F. Douglas, Sushil K. Satija, D L. Goldfarb, H Ito
The depth profile of the counterion concentration within thin polyelectrolyte films was measured in situ using contrast variant specular neutron reflectivity to characterize the initial swelling stage of the film dissolution.Wefind substantial counterion

Boundary Lubricated Wear

July 15, 2005
Author(s)
Stephen M. Hsu, R G. Munro, M C. Shen, Richard S. Gates
This chapter reviews the fundamental nature of wear under lubricated conditions and presents a comprehensive view of our current understanding of the wear processes under boundary lubrication conditions. Wear under lubricated conditions can be classified

Hyperfine Coherence in the Presence of Spontaneous Photon Scattering

July 15, 2005
Author(s)
R Ozeri, C. Langer, John D. Jost, B. L. DeMarco, A. Ben-Kish, Brad R. Blakestad, Joseph W. Britton, J Chiaverini, Wayne M. Itano, David Hume, Dietrich G. Leibfried, Till P. Rosenband, Piet Schmidt, David J. Wineland
The coherence of hyperfine-state superpositions of a trapped 9Be + ion is experimentally studied in the presence of off-resonant light. It is shown that Rayleigh elastic scattering of photons that does not change state populations also does not affect

mLab: A Mobile Ad Hoc Network Test Bed

July 14, 2005
Author(s)
Tom T. Karygiannis, Emmanouil Antonakakis
Over the last few years, research in the area of mobile ad hoc networks (MANETs) has focused on routing protocol performance improvements, security enhancements, power consumption optimizations, and quality of service metrics. The availability of

Knowledge Representation and Decision Making for Mobile Robots

July 13, 2005
Author(s)
Elena R. Messina, Stephen B. Balakirsky
Knowledge is central to a mobile robot's ability to carry out its missions and adapt to changes in the environment it is traversing. The knowledge subsystem must support acquisition of information from external sources, maintain prior knowledge, infer new

Toward an Improved Color Rendering Metric

July 13, 2005
Author(s)
Wendy L. Davis, Yoshihiro Ohno
Several aspects of the Color Rendering Index (CRI) are flawed, limiting its usefulness in assessing the color rendering capabilities of LEDs for general illumination. At NIST, we are developing recommendations to modify the CRI that would overcome these

Vapor pressures of n-heptane determined by comparative ebulliometry

July 13, 2005
Author(s)
Jesus Sanchez Ochoa, Michael B. Ewing
The vapor pressures of n-heptane have been measured using comparative ebulliometry with water as the reference substance. The measurements cover the temperature and pressure range 372 K and 102 kPa to 537 K and 2621 kPa and were correlated by a Wagner type
Displaying 36701 - 36725 of 74164
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