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Displaying 26 - 50 of 108

A Spin-1/2 Optical Lattice Clock

August 7, 2009
Author(s)
Nathan D. Lemke, Andrew D. Ludlow, Zeb Barber, Tara M. Fortier, Scott A. Diddams, Yanyi Jiang, Steven R. Jefferts, Thomas P. Heavner, Thomas E. Parker, Christopher W. Oates
We experimentally investigate an optical clock based on 171Yb (I = 1/2) atoms confined in an optical lattice. We have evaluated all known frequency shifts to the clock transition, including the density-dependent collision shift, with an uncertainty of 0.19

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

A simplified optical lattice clock

April 2, 2009
Author(s)
N Poli, M.G. Tarallo, M. Schioppo, A. Alberti, Giorgio Ferrari, V. Ivanov, Christopher W. Oates, G.M. Tino
While existing optical lattice clocks demonstrate a high level of performance, they remain complex experimental devices. In order to address a wider range of applications including those requiring transportable devices, it will be necessary to simplify the

Keeping time in three dimensions

December 1, 2008
Author(s)
Christopher W. Oates
Here I review a paper by Akatsuka et al. that appears in the current volume of Nature Physics. This work describes their latest experimental results on optical lattice clocks, including the first demonstration of a 3-D lattice clock.

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.

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

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

Stable Laser System for Probing the Clock Transition at 578 nm in Neutral Ytterbium

May 29, 2007
Author(s)
Christopher W. Oates, Zeb Barber, Jason Stalnaker, C Hoyt, Tara M. Fortier, Scott A. Diddams, Leo W. Hollberg
In this paper we describe a new laser system we have developed to probe the ultra-narrow 1S 0 -> 3P 0 clock transition at 578 nm in neutral ytterbium. The yellow light is produced by sum frequency generation in a periodically-poled waveguide. With

Absolute frequency measurement of the neutral 40 Ca optical frequency standard at 657 nm based on microkelvin atoms

March 14, 2007
Author(s)
G Wilpers, Christopher W. Oates, Scott A. Diddams, A Bartels, Tara M. Fortier, Windell Oskay, James C. Bergquist, Steven R. Jefferts, Thomas P. Heavner, Thomas E. Parker, Leo W. Hollberg
We report an absolute frequency measurement of the optical clock transition at 657 nm in 40Ca with a relative uncertainty of 7.5x10 -15, the most accurate frequency measurement of a neutral atom optical transition to date. Relative instabilities of 2x10

Frequency Uncertainty for Optically Referenced Femtosecond Laser Frequency Combs

February 1, 2007
Author(s)
Long-Sheng Ma, Zhiyi Bi, A Bartels, Kyoungsik Kim, Lennart Robertsson, Massimo Zucco, Robert Windeler, G Wilpers, Christopher W. Oates, Leo W. Hollberg, Scott Diddams
We present measurements and analysis of the currently known residual frequency uncertainty of femtosecond laser frequency combs (FLFCs) based on Kerr-lens mode-locked Ti:sapphire lasers. Broadband frequency combs generated directly from the laser

Kilohertz-level spectroscopy of cold atoms with a femtosecond optical frequency comb

October 19, 2006
Author(s)
Tara Fortier, Yann Le Coq, Jason Stalnaker, Davi Ortega, Scott Diddams, Christopher W. Oates, Leo W. Hollberg
We have performed sub-Doppler spectroscopy on the narrow intercombination line of cold calcium atoms using the amplified output of a femtosecond laser frequency comb. Injection locking of a 657-nm diode laser with a femtosecond comb allowed for two regimes

Stability measurements of the Ca and Yb Optical Frequency Standards

June 5, 2006
Author(s)
Christopher W. Oates, C Hoyt, Yann Le Coq, Zeb Barber, Tara M. Fortier, Jason Stalnaker, Scott A. Diddams, Leo W. Hollberg
In this paper we describe two types of optical atomic clocks. The first is based on freely expanding calcium atoms and is optimized for experimental simplicity and high stability. The second is based on Yb atoms confined to an optical lattice that is

A Compact High Stability Optical Clock Based on Laser-Cooled Ca

March 27, 2006
Author(s)
Christopher W. Oates, Yann LeCoq, G Wilpers, Leo W. Hollberg
We report new measurements and modifications for a simple, compact, Ca atomic clock at 657 nm. External measurements were made against an independent Yb lattice optical clock via a fs-laser frequency comb. These results lead to upper limits of the Ca clock

Spectroscopy of neutral 174 Yb in a one-dimensional optical lattice

March 27, 2006
Author(s)
C Hoyt, Zeb Barber, Christopher W. Oates, A. V. Taichenachev, V. I. Yudin, Leo W. Hollberg
We report spectroscopy of the 1S 0 - 3P 0 clock transition in neutral 174Yb atoms confined to a one- dimensional optical lattice at the ac Stark shift-canceling wavelength of 759.35 nm. Spectroscopic linewidths as narrow as 4 Hz, full width at half-maximum

Magnetic field-induced spectroscopy of strongly forbidden optical transitions

March 3, 2006
Author(s)
Alexey Taychenachev, V Yudin, Christopher W. Oates, C Hoyt, Zeb Barber, Leo W. Hollberg
We propose a method that uses a static magnetic field to enable direct optical excitation of forbidden electric dipole transitions that are otherwise prohibitively weak. The method is based on mixing of atomic states by a static magnetic field. The method