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Topic Area: Physics

Displaying records 61 to 70 of 642 records.
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61. A high stability optical frequency reference based on thermal calcium atoms
Topic: Physics
Published: 5/24/2012
Authors: Richard W Fox, Jeffrey Aaron Sherman, W. Douglas, Judith Berget Olson, Andrew D Ludlow, Christopher W Oates
Abstract: Here we report an imprecision below 10^u-14^ with a simple, compact optical frequency standard based upon thermal calcium atoms. Using a Ramsey-Borde spectrometer we excite features with linewidths < 5 kHz for the ^u1^S^d0^-^u3^P^d1^ intercombinati ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=911604

62. A hybrid 10 GHz photonic-microwave oscillator with sub-femtosecond absolute timing jitter
Topic: Physics
Published: 5/24/2012
Authors: Tara Michele Fortier, Craig W Nelson, Archita Hati, Franklyn J Quinlan, Jennifer A. Taylor, Haifeng (Haifeng) Jiang, Chin W. Chou, Nathan D. Lemke, Andrew D Ludlow, David Allan Howe, Christopher W Oates, Scott A Diddams
Abstract: We demonstrate a 10 GHz hybrid oscillator comprised of a phase stabilized optical frequency comb divider and a room temperature dielectric sapphire oscillator. Characterization of the 10 GHz microwave signal via comparison of two independent hybrid ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=911633

63. A new algorithm for clock weights for the SIM time scale
Topic: Physics
Published: 5/24/2012
Authors: Michael A Lombardi, J. Mauricio Lopez-Romero, Nelida Diaz-Munoz, E. de Carlos-Lopez
Abstract: A time and frequency comparison system has been developed for the Sistema Interamericano de Metrologia (SIM) region in order to compare in real time the time references maintained at the SIM national metrology institutes (NMIs). Since January 2010 a ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=911482

64. Blackbody effects in the Yb optical lattice clock
Topic: Physics
Published: 5/24/2012
Authors: Andrew D Ludlow, Jeffrey Aaron Sherman, Nathan D. Lemke, Kyle Patrick Beloy, Nathan Morris Bjork Hinkley, M. Pizzocaro, Richard W Fox, Christopher W Oates
Abstract: We report a high accuracy measurement of the differential static polarizability for the clock transition in a Yb lattice clock, a key parameter for determining the blackbody BBR) shift of this transition. We further report efforts to determine the 6s ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=911630

65. Common-Arm Counter Propagating Phase Bridge for Vibration Sensitivity Measurement
Topic: Physics
Published: 5/24/2012
Authors: Danielle Grace Lirette, Corey A. Barnes, Archita Hati, Jason Anthony DeSalvo, Craig W Nelson, David Allan Howe
Abstract: Current methods for measuring the vibration sensitivity of microwave devices are primarily limited by choice of cables connecting a stationary platform to a vibrating actuator. We experimentally compare the current ("conventional") method with a new ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=911524

66. Mechanical stabilization of a microrod-resonator optical frequency
Topic: Physics
Published: 5/24/2012
Authors: Scott Brian Papp, Pascal Patrice Del'Haye, Scott A Diddams
Abstract: We present line-spacing frequency control of a microresonator-based optical frequency comb by way of mechanical actuation. Using this novel technique we have achieved a record level of residual stability in the line spacing of 5 {multiply} 10^u-15^ ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=911631

67. PM-AM Correlation Measurements and Analysis
Topic: Physics
Published: 5/24/2012
Authors: David Allan Howe, Archita Hati, Craig W Nelson, Danielle Grace Lirette
Abstract: We measure and analyze effects of nonlinear mixing of phase-noise modulation (PM) and amplitude-noise modulation (AM) in an oscillating signal by real-time correlations measured in the cross power spectral density (CPSD). We outline sensitive measur ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=911532

68. Phase-Noise Measurement of a 670 GHz Source
Topic: Physics
Published: 5/24/2012
Authors: Jason Anthony DeSalvo, Archita Hati, Craig W Nelson, David Allan Howe
Abstract: We present phase-noise measurements in support of terahertz electronics. Using digital phase-noise measurement techniques and an even-harmonic mixer, we achieve a phase-noise measurement system in waveguide (WR1.5). At 670 GHz an upper bound of thi ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=911527

69. Ultra-low-noise Regenerative Frequency Divider for High Spectral Purity RF Signal Generation
Topic: Physics
Published: 5/24/2012
Authors: Archita Hati, Craig W Nelson, Corey A. Barnes, Danielle Grace Lirette, Jason Anthony DeSalvo, Tara Michele Fortier, Franklyn J Quinlan, Andrew D Ludlow, Till P Rosenband, Scott A Diddams, David Allan Howe
Abstract: We implement an ultra-low-noise frequency divider chain from 8 GHz to 5 MHz that utilizes custom-built regenerative frequency divide-by-2 circuits. The single-sideband (SSB) residual phase noise of this regenerative divider at 5 MHz output is -163 dB ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=911522

70. Vibrational analysis of stabilized lasers
Topic: Physics
Published: 5/24/2012
Authors: Kenneth Jeramiah Hughes, Archita Hati, Craig W Nelson, David Allan Howe
Abstract: Frequency-stabilized lasers are routinely used in a variety of research and application areas relating to laser-cooled atoms. Important applications in the cold-atom regime include atomic time keeping, inertial navigation, gravitational sensing, and ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=911603