U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Physics

Search Publications

Search Title, Abstract, Conference, Citation, Keyword or Author
  • Published Date
Displaying 1326 - 1350 of 2516

Phase-coherent microwave-to-optical link with a self-referenced microcomb

June 6, 2016
Author(s)
Pascal P. Del'Haye, Aurelien C. Coillet, Tara M. Fortier, Katja M. Beha, Daniel C. Cole, Hansuek Lee, Kerry J. Vahala, Scott B. Papp, Scott A. Diddams
The counting and control of optical cycles of light has become common with modelocked laser frequency combs. But even with advances in laser technology, modelocked laser combs remain bulk-component devices that are hand-assembled. In contrast, a frequency

Single-frequency 571 nm VECSEL for photoionization of magnesium

June 3, 2016
Author(s)
Shaun C. Burd, Tomi Leinonen, Jussi-Pekka Penttinen, David T. Allcock, Daniel H. Slichter, Raghavendra Srinivas, Andrew C. Wilson, Micrea Guina, Dietrich G. Leibfried
We report the development of an intracavity-frequency-doubled VECSEL emitting at 571 nm for photoionization of magnesium. The laser employs a V-cavity geometry with a gain chip at the end of one cavity arm and a lithium triborate (LBO) crystal for second

Oscillator metrology with software defined radio

May 24, 2016
Author(s)
Jeffrey A. Sherman, Robert Jordens
Analog electrical elements such as mixers, filters, transfer oscillators, isolating buffers, dividers, and even transmission lines contribute technical noise and unwanted environmental coupling in time and frequency measurements. Software defined radio

Visualizing edge states with an atomic Bose gas in the quantum Hall regime

May 19, 2016
Author(s)
Ian B. Spielman, Ben Stuhl, Hsin I Lu, Lauren M. Aycock, Dina Genkina
We engineered a two-dimensional magnetic lattice in an elongated strip geometry, with effective per-plaquette flux $\approx4/3$ times the flux quanta. We imaged the localized edge and bulk states of atomic Bose-Einstein condensates in this strip. Further

State of the Field: Extreme Precision Radial Velocities

May 17, 2016
Author(s)
Debra A. Fischer, Guillem Anglada-Escude, Pamela Arriagada, Roman V. Baluev, Jacob L. Bean, Lars A. Buchhave, Abhijit K. Chakraborty, Scott Diddams, Gabor Furesz, B. S. Gaudi, Philip C. Gregory, Frank Grundahl, Guillaume Hebrard, David W. Hogg, Andrew W. Howard, Colby A. Jurgenson, David W. Latham, Greg Laughlin, Thomas J. Loredo, Suvrath Mahadevan, Tyler M. McCracken, Mario R. Perez, David F. Phillips, P Plavchan, Lisa Prato, Andreas Quirrenbach, Paul Robertson, David Sawyer, Jason D. Eastman, Pedro Figueira, Eric B. Ford, Daniel Foreman-Mackey, Paul Fournier, John A. Johnson, Christophe Lovis, Francesco Pepe, Francesco Pepe, Ansgar Reiners, Nuno C. Santos, Damien Segransan, Alessandro Sozzetti, Thorsten Carroll, Francois Bouchy, Paul Jorden, Tilo Steinmetz, Xavier Dumusque, Artie P. Hatzes, Enrique Herrero, Michael Endl, Andrew Szentgyorgyi
The Second Workshop on Extreme Precision Radial Velocities defined circa 2015 the state of the art Doppler precision and identified the critical path challenges for reaching 10 cm/s measurement precision. The presentations and discussion of key issues for

Testing of Cementitious Materials Using a Dynamic MEMS Micro Rheometer

May 17, 2016
Author(s)
Yong Sik Kim, Nicholas G. Dagalakis, Chiara C. Ferraris, Nicos Martys
Incompatibility of cementitious materials with admixtures often requires time consuming testing. Usually, several mixtures need to be prepared either using concrete or paste to determine the optimum high range water reducer dosage (HRWRA) and type. The

Electrical Units in the New SI: Saying Goodbye to the 1990 Values

May 12, 2016
Author(s)
Nick Fletcher, Gert Rietveld, James K. Olthoff, Ilya F. Budovsky
The proposed redefinition of several SI base units is a topic that has been on the metrology agenda for the last decade. The general principles and the motivation for the changes have been presented at the NCSLI several times. However, recent progress on

DELAY MEASUREMENT OF 1PPS SIGNALS IN TIMING SYSTEMS

May 9, 2016
Author(s)
Stefania Romisch, Daniele Rovera, Marco Siccardi
Abstract The uncertainty of time measurements in timing systems is not only a function of the quality of the instruments and system components (time interval counters, pulse distribution amplifiers, GNSS receivers) but lays also in the quality of the

Measurement of AM-to-PM Conversion in a Quartz-MEMS Resonator

May 9, 2016
Author(s)
Craig W. Nelson, Archita Hati, David A. Howe
This work investigates the new aspects of the non-linear response in a quartz-MEMS resonator at 635 MHz. We characterize its major cause of AM-to-PM conversion as a function of power and drive frequency; this is important in developing noise compensation

Power Splitter Thermal Noise Correlations in Cross-spectrum Noise Measurements

May 9, 2016
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe
We discuss collapse of the cross-spectrum phase noise measurement of thermally-limited oscillator due to anti-correlated thermal noise of the Wilkinson power splitter. We also examine effect of thermal noise of various resistive power splitters on such

Practical Evaluation of a 50 km Fiber Link Utilizing a Commercial Modem

May 9, 2016
Author(s)
Corey A. Barnes, Archita Hati, Craig W. Nelson, David A. Howe
We evaluate the stability of two-way time and frequency transfer over a 50 km fiber optic link established using a commercially available fiber optic modem. For this evaluation we report the residual phase noise, total Allan deviation, total time deviation

Frequency shift mitigation in a cold-atom CPT clock

May 8, 2016
Author(s)
Xiaochi Liu, John Kitching, Elizabeth Donley, Eugene N. Ivanov
An upgrade in the laser interrogation system for our cold-atom clock based on coherent population trapping has resulted in a reduced light shift. The new approach makes use of an electro-optic modulator to significantly reduce the phase coherence of the

Magnetic phases of spin-1 spinorbit-coupled Bose gases

May 1, 2016
Author(s)
Ian B. Spielman, Daniel Campbell, Ryan Price, Ana Valdes-Curiel, Andika Putra, Dimitrius Trypogeorgos
Phases of matter are characterized by order parameters describing the type and degree of order in a system. Here we experimentally explore the magnetic phases present in a near-zero temperature spin-1 spin–orbit-coupled atomic Bose gas and the quantum

"Perpendicular laser cooling with a rotating wall potential in a Penning trap"

April 26, 2016
Author(s)
Joseph W. Britton, Justin G. Bohnet, John Bollinger, Steven B. Torrisi
We investigate the impact of a rotating wall potential on perpendicular laser cooling in a Penning ion trap. By including energy exchange with the rotating wall, we extend previous Doppler laser cooling theory and show that low perpendicular temperatures

A Study on Reducing the Diurnal in the Europe-to-Europe TWSTFT Links.

April 4, 2016
Author(s)
Victor S. Zhang, Thomas E. Parker, Shengkang Zhang
Most of the Two-Way Satellite Time and Frequency Transfer (TWSTFT or TW) links exhibit a daily variation (diurnal) on the order of 1 ns in the differences. The stability of TW is degraded by the diurnal. Many studies on the sources of diurnal have been

Cross-spectral Collapse from Anti-correlated Thermal Noise in Power Splitters

April 4, 2016
Author(s)
Craig Nelson, Archita Hati, David A. Howe
We discuss the cross-spectral collapse due to anti-correlated thermal noise that originates from the common-mode power divider (splitter) in a cross-spectrum noise measurement system. We studied this effect for different power splitters and discuss its

Extended Source Interferometry in the Compact Regime

April 4, 2016
Author(s)
Bruno M. Pelle, Gregory W. Hoth, Stefan Riedl, John E. Kitching, Elizabeth A. Donley
We present an atom interferometer based on an expanding cloud of laser-cooled atoms sensitive to rotations along two axes and acceleration along one axis in an effective volume of 1 cm3. We observed spatially resolved fringes by imaging the expanding cloud
Was this page helpful?