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Search Publications by: Scott Diddams (Assoc)

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Displaying 126 - 150 of 320

Probing interactions between ultracold fermions

April 17, 2009
Author(s)
G K. Campbell, M M. Boyd, J W. Thomsen, M J. Martin, S Blatt, M D. Swallows, Travis L. Nicholson, Tara Fortier, Christopher W. Oates, Scott Diddams, Nathan D. Lemke, Pascal Naidon, Paul S. Julienne, Jun Ye, Andrew Ludlow
At ultracold temperatures, the Pauli exclusion principle suppresses collisions between identical fermions. This has motivated the development of atomic clocks using fermionic isotopes. However, by probing an optical clock transition with thousands of

Generation of 20 GHz, sub-40 fs pulses at 960 nm via repetition rate multiplication

April 1, 2009
Author(s)
Matthew S. Kirchner, Danielle Braje, Tara M. Fortier, A.M. Weiner, Leo Hollberg, Scott A. Diddams
Optical filtering of a stabilized 1 GHz optical frequency comb produces a 20 GHz comb with ~40 nm bandwidth (FWHM) at 960 nm. Using a low finesse Fabry-Perot cavity in a double pass configuration provides a broad cavity coupling bandwidth (delta lambda

Improved signal-to-noise ratio of 10 GHz microwave signals generated with a mode-filtered femtosecond laser frequency comb

February 18, 2009
Author(s)
Scott A. Diddams, Matthew S. Kirchner, Tara M. Fortier, Danielle Braje, A. M. Weiner, Leo W. Hollberg
We use a Fabry-Perot cavity to optically filter the output of a Ti:sapphire frequency comb to integer multiples of the original 1 GHz mode spacing. This effectively increases the pulse repetition rate which is useful for several applications. In the case

Yb Optical Lattice Clock

November 23, 2008
Author(s)
Nathan D. Lemke, Andrew Ludlow, Zeb Barber, N Poli, C.W. Hoyt, Long-Sheng Ma, Jason Stalnaker, Christopher W. Oates, Leo Hollberg, James C. Bergquist, A. Brusch, Tara Fortier, Scott Diddams, Thomas P. Heavner, Steven R. Jefferts, Tom Parker
We describe the development and latest results of an optical lattice clock based on neutral Yb atoms, including investigations based on both even and odd isotopes. We report a fractional frequency uncertainty below 10 -15 for 171Yb.

Alpha-Dot or Not: Comparison of Two Single Atom Optical Clocks

October 5, 2008
Author(s)
Till P. Rosenband, David Hume, Chin-Wen Chou, J.C. Koelemeij, A. Brusch, Sarah Bickman, Windell Oskay, Tara M. Fortier, Jason Stalnaker, Scott A. Diddams, Nathan R. Newbury, William C. Swann, Wayne M. Itano, David J. Wineland, James C. Bergquist
Repeated measurements of the frequency ratio of Hg + and Al + single-atom optical clocks over the course of a year yield a constraint on the possible temporal variation of the fine-structure constant a. The time variation of the measured ratio corresponds

Recent atomic clock comparisions at NIST

October 1, 2008
Author(s)
Luca Lorini, Neil Ashby, Anders Brusch, Scott Diddams, Robert E. Drullinger, Eric Eason, Tara Fortier, Pat Hastings, Thomas P. Heavner, David Hume, Wayne M. Itano, Steven R. Jefferts, Nathan R. Newbury, Tom Parker, Till P. Rosenband, Jason Stalnaker, William C. Swann, David J. Wineland, James C. Bergquist
The record of atomic clock frequency comparisons at NIST over the past half-decade provides one of the tightest constraints of any present-day, temporal variations of the fundamental constants. Notably, the 6-year record of increasingly precise

Ratio of the Al + and Hg + Optical Clock Frequencies to 17 Decimal Places

August 25, 2008
Author(s)
Wayne M. Itano, Till P. Rosenband, David Hume, P.O. Schmidt, Chin-Wen Chou, A. Brusch, Luca Lorini, Windell Oskay, Robert E. Drullinger, Sarah Bickman, Tara M. Fortier, Jason Stalnaker, Scott A. Diddams, William C. Swann, Nathan R. Newbury, David J. Wineland, James C. Bergquist
Frequency standards (atomic clocks) based on narrow optical transitions in 27Al + and 199Hg + have been developed over the past several years at NIST. These two types of standards are both based on single ions confined in Paul traps, but differ in the

Passively mode-locked 10 GHz femtosecond Ti:sapphire laser

August 15, 2008
Author(s)
A Bartels, Dirk Heinecke, Scott Diddams
We report a mode-locked Ti:sapphire femtosecond laser emitting pulses as short as 42 fs at 10 GHz repetition rate. When operated with a spectrally-integrated average power greater than 1 W, the associated femtosecond laser frequency comb (FLFC) contains

Towards a Low-Jitter 10 GHz Pulsed Source with an Optical Frequency Comb Generator

June 9, 2008
Author(s)
Shijun Xiao, Leo W. Hollberg, Nathan R. Newbury, Scott A. Diddams
We demonstrate low residual timing jitter of 10 GHz pulses from a 1.55 m optical frequency comb generator based on a doubly-resonant electro-optic modulator. The comb spectral phase is shown to be linear for each sideband but of different slopes. The

Astronomical spectrograph calibration with broad-spectrum frequency combs

May 29, 2008
Author(s)
Danielle Braje, Matthew S. Kirchner, Tara M. Fortier, Scott A. Diddams, Leo W. Hollberg, Steve Osterman
Broad-band frequency combs are filtered to spectrographically resolvable frequency-mode spacing, and the limitations of using cavities for spectral filtering are considered. Data and theory are used to show implications to spectrographic calibration of

Frequency evaluation of the doubly forbidden 1 S 0 - 3 P 0 transition in bosonic 174 Yb

May 6, 2008
Author(s)
Nicola Poli, Zeb Barber, Nathan D. Lemke, Christopher W. Oates, Tara Fortier, Scott Diddams, Leo W. Hollberg, James C. Bergquist, Anders Brusch, Steven R. Jefferts, Thomas P. Heavner, Tom Parker
We report an uncertainty evaluation of an optical lattice clock based on the 1S 0 – 3P 0 transition in the bosonic isotope 174Yb using magnetically induced spectroscopy. The uncertainty due to systematic effects has been reduced to less than 0.8Hz, which

Sr Lattice Clock at 1 x 10 -16 Fractional Uncertainty by Remote Optical Evaluation with a Ca clock

March 28, 2008
Author(s)
A D. Ludlow, T Zelevinsky, G K. Campbell, S Blatt, M M. Boyd, M de Miranda, M J. Martin, S M. Foreman, J Ye, Tara M. Fortier, Jason Stalnaker, Scott A. Diddams, Yann LeCoq, Zeb Barber, Nicola Poli, Nathan D. Lemke, K. Beck, Christopher W. Oates
Optical atomic clocks promise timekeeping at the highest precision and accuracy, owing to their high operating frequency. The most accurate optical clocks are presently based on single trapped ions1, due to the exquisite control possible over their

Optical Lattice Induced Light Shifts in a Yb Atomic Clock

March 14, 2008
Author(s)
Zeb Barber, Jason Stalnaker, Nathan D. Lemke, Christopher W. Oates, Tara M. Fortier, Scott A. Diddams, Leo W. Hollberg, C Hoyt
We present an experimental study of the lattice induced light shifts on the $^1S_0\rightarrow\,^3P_0$ clock transition of ytterbium. The ``magic'' frequency for the $^{174}$Yb isotope was determined to be $u_{magic} = 394\,799\,475(35)$MHz. The

Frequency ratio of Al + and Hg + single-ion optical clocks; metrology at the 17th decimal place

March 6, 2008
Author(s)
Till P. Rosenband, David Hume, P. O. Schmidt, Chin-Wen Chou, Anders Brusch, Luca Lorini, Windell Oskay, Robert E. Drullinger, Tara M. Fortier, Jason Stalnaker, Scott A. Diddams, Nathan R. Newbury, W Swann, Wayne M. Itano, David J. Wineland, James C. Bergquist
We report the frequency ratio of the two most accurate and stable atomic clocks with a total fractional uncertainty of 5.2 X 10 -17 . This frequency ratio is the best-known physical constant that is not a simple integer. Repeated measurements during the

Optical-to-microwave frequency comparison with fractional uncertainty of 10 -15

October 1, 2007
Author(s)
Jason Stalnaker, Scott A. Diddams, Tara M. Fortier, K Kim, Leo W. Hollberg, James C. Bergquist, Wayne M. Itano, Marie Delaney, Luca Lorini, Windell Oskay, Thomas P. Heavner, Steven R. Jefferts, Filippo Levi, Thomas E. Parker, Jon H. Shirley
We report the technical aspects of the optical-to-microwave comparison for our recent measurements of the optical frequency of the mercury single-ion frequency standard in terms of the SI second as realized by the NIST-F1 cesium fountain clock. Over the

A proposed laser frequency comb based wavelength reference for high resolution spectroscopy

September 12, 2007
Author(s)
Steve Osterman, Scott A. Diddams, Matthew Beasley, Cynthia Froning, Leo W. Hollberg, Phillip MacQueen, Vela Mbele, Andrew Weiner
High resolution spectroscopy is the foundation for many of the most challenging and productive of all astronomical observations. A highly precise, repeatable and stable wavelength calibration is especially essential for long term RV observations. The two

Lattice-based optical clock using an even isotope of Yb

September 12, 2007
Author(s)
Zeb Barber, C Hoyt, Jason Stalnaker, Nathan D. Lemke, Christopher W. Oates, Tara M. Fortier, Scott A. Diddams, Leo W. Hollberg
We describe progress toward an optical lattice clock based on an even isotope of Yb. The 1S_0 - P_0 clock resonance in 174Yb is accessed using a magnetically induced spectroscopic technique. Using ~1 mT static magnetic fields and ~10 uW of probe light