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Search Publications by: Tara Fortier (Fed)

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Displaying 26 - 50 of 178

Measurements of 25 Mg + and 27 Al + magnetic constants for improved ion clock accuracy

July 15, 2019
Author(s)
Samuel M. Brewer, Jwo-Sy Chen, Aaron M. Hankin, Ethan Clements, Chin-wen Chou, Kyle Beloy, Will McGrew, Xiaogang Zhang, Robert J. Fasano, Daniele Nicolodi, Holly Leopardi, Tara Fortier, Scott Diddams, Andrew Ludlow, David J. Wineland, David Leibrandt, David Hume
We have measured the quadratic Zeeman coefficient for the 3P0 excited electronic state in 27Al+, C2=-71.944(24) MHz/T2 and the hyperfine constant of the 25Mg+ 2S1/2 ground electronic state, Ahfs = -596 254 250.981(45) Hz, with improved uncertainties. Both

Towards the optical second: verifying optical clocks at the SI limit

April 11, 2019
Author(s)
William F. McGrew, Xiaogang Zhang, Robert J. Fasano, Holly Leopardi, Daniele Nicolodi, Kyle P. Beloy, Jian Yao, Jeffrey A. Sherman, Stefan A. Schaeffer, Joshua J. Savory, Stefania Romisch, Christopher W. Oates, Thomas E. Parker, Tara M. Fortier, Andrew D. Ludlow
The pursuit of ever more precise measures of time and frequency motivates redefinition of the second in terms of an optical atomic transition. To ensure continuity with the current definition, based on the microwave hyperfine transition in 133Cs, it is

Optimizing linearity in high-speed photodiodes

November 7, 2018
Author(s)
Josue Davila-Rodriguez, X. Xie, J. Zang, Christian J. Long, Tara M. Fortier, Holly F. Leopardi, Takuma Nakamura, J. C. Campbell, Scott A. Diddams, Franklyn J. Quinlan
Analog photonic links require high fidelity, high speed optical-to-electrical conversion for applications such as radio-over-fiber, synchronization at kilometer-scale facilities, and low- noise electronic signal generation. Nonlinearity is a particularly

Progress on Optical-clock-based Time Scale at NIST: Simulations and Preliminary Real-Data Analysis

April 20, 2018
Author(s)
Jian Yao, Jeffrey A. Sherman, Tara M. Fortier, Thomas E. Parker, Judah Levine, Joshua J. Savory, Stefania Romisch, William F. McGrew, Robert J. Fasano, Stefan A. Schaeffer, Kyle P. Beloy, Andrew D. Ludlow
This paper shows the recent NIST work on incorporating an optical clock into a time scale. We simulate a time scale composed of continuously-operating commercial hydrogen masers and an optical frequency standard that does not operate continuously as a

Incorporating an Optical Clock into a Time Scale at NIST: Simulations and Preliminary Real-Data Analysis

March 29, 2018
Author(s)
Jian Yao, Jeffrey A. Sherman, Tara M. Fortier, Thomas E. Parker, Judah Levine, Joshua J. Savory, Stefania Romisch, William F. McGrew, Robert J. Fasano, Stefan A. Schaeffer, Kyle P. Beloy, Andrew D. Ludlow
This paper shows the recent NIST work on incorporating an optical clock into a time scale. We simulate a time scale composed of continuously-operating commercial hydrogen masers and an optical frequency standard that does not operate continuously as a

Hyperpolarizability and Operational Magic Wavelength in an Optical Lattice Clock

December 19, 2017
Author(s)
Roger C. Brown, Nate B. Phillips, Kyle P. Beloy, William F. McGrew, Marco Schioppo, Robert J. Fasano, Gianmaria Milani, Xiaogang Zhang, Nathan M. Hinkley, Holly F. Leopardi, T H. Yoon, Daniele Nicolodi, Tara M. Fortier, Andrew D. Ludlow
Optical clocks benefit from tight atomic confinement enabling extended interrogation times as well as Doppler- and recoil-free operation. However, these benefits come at the cost of frequency shifts that, if not properly controlled, may degrade clock

Temperature dependence of nonlinearity in high-speed, high-power photodetectors

September 30, 2017
Author(s)
Josue Davila-Rodriguez, Holly Leopardi, Tara Fortier, Xiaojun Xie, Joe C. Campbell, James Booth, Nate Orloff, Scott Diddams, Franklyn Quinlan
We present an experimental study of the nonlinearity of modified uni-traveling carrier (MUTC) photodiodes at cryogenic temperatures. At 120 K, the amplitudeto-phase (AM-to-PM) conversion nonlinearity is reduced by up to 10 dB, resulting in nearly 40 dB AM

Photonic-Chip Supercontinuum with Tailored Spectra for Counting Optical Frequencies

July 24, 2017
Author(s)
David R. Carlson, Daniel D. Hickstein, Alexander J. Lind, Judith B. Olson, Richard W. Fox, Roger C. Brown, Andrew D. Ludlow, Qing Li, Daron A. Westly, Tara M. Fortier, Kartik A. Srinivasan, Scott A. Diddams, Scott B. Papp
Supercontinuum generation using chip-integrated photonic waveguides is a powerful approach for spectrally broadening pulsed laser sources with very low pulse energies and compact form factors. When pumped with a mode-locked laser frequency comb, these

A compact, thermal noise limited reference cavity for ultra-low noise microwave generation

March 23, 2017
Author(s)
Josue Davila-Rodriguez, Frederick N. Baynes, Andrew D. Ludlow, Tara M. Fortier, Holly F. Leopardi, Scott A. Diddams, Franklyn J. Quinlan
A 25 mm long, rigidly-held, ultra-stable optical frequency reference cavity is demonstrated. The cavity spacer has an easy-to-manufacture cylindrical shape which nonetheless exhibits a holding geometry predicted to be first-order insensitive to the

Optically referenced broadband electronic synthesizer with 15 digits of resolution

September 5, 2016
Author(s)
Franklyn J. Quinlan, Tara M. Fortier, A. Rolland, Frederick N. Baynes, A. J. Metcalf, Archita Hati, Andrew D. Ludlow, Nathan M. Hinkley, M. Shimizu, Joe Campbell, Scott A. Diddams
Increasing demands in the high tech industry for higher data rates and better synchronization necessitates the development of new wideband and tunable sources with improved noise performance over traditional synthesis based quartz oscillators. Precision

Microresonator Brillouin laser stabilization using a microfabricated rubidium cell

June 17, 2016
Author(s)
William Loh, Matthew T. Hummon, Holly Leopardi, Tara Fortier, Franklyn Quinlan, John Kitching, Scott Papp, Scott Diddams
We frequency stabilize the output of a miniature stimulated Brillouin scattering (SBS) laser to rubidium atoms in a microfabricated cell to realize a laser system with frequency stability at the 10-11 level over seven decades in averaging time. In addition

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