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Search Publications by: Andrew Ludlow (Fed)

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Displaying 51 - 75 of 117

Progress on the Optical Lattice Clock

June 1, 2015
Author(s)
Andrew D. Ludlow, Jun Ye
We summarize recent research in the development of the optical lattice clock, with particular focus on the ytterbium and strontium lattice clocks being developed at NIST and JILA. We highlight recent progress in improving the stability and uncertainty of

Optical atomic clocks

February 9, 2015
Author(s)
Andrew D. Ludlow, Martin M. Boyd, Jun Ye, E. Peik, P. O. Schmidt
Optical atomic clocks represent the state-of-the-art in the frontier of modern measurement science. In this article we provide a detailed review on the development of optical atomic clocks that are based on trapped single ions and many neutral atoms. We

Optical Lattice Clocks

January 1, 2015
Author(s)
Andrew D. Ludlow, Christopher W. Oates
Here we introduce and give a basic description of optical lattice clocks. We also briefly describe recent advances in these atomic frequency standards, looking to future work and applications.

Atomic Clock with 1x10 -18 Room-Temperature Blackbody Stark Uncertainty

December 31, 2014
Author(s)
Kyle P. Beloy, Nathan M. Hinkley, Nate B. Phillips, Jeffrey A. Sherman, Marco Schioppo, John H. Lehman, Ari D. Feldman, Leonard M. Hanssen, Christopher W. Oates, Andrew D. Ludlow
The Stark shift due to blackbody radiation (BBR) is a key factor limiting the performance of many atomic frequency standards, with the BBR environment inside the clock apparatus being difficult to characterize at a high level of precision. Here we

Quantum engineering of atomic phase shifts in optical clocks

November 24, 2014
Author(s)
Andrew D. Ludlow, T Zanon-willette, S. Almonacil, E. de Clercq, Ennio Arimondo
Quantum engineering of time-separated Raman laser pulses in three-level systems is presented to produce an ultra-narrow, optical-clock transition free from light shifts and with a significantly reduced sensitivity to laser parameter fluctuations. Based on

An atomic clock with 10 -18 instability

September 13, 2013
Author(s)
Andrew D. Ludlow, Nathan M. Hinkley, Jeffrey A. Sherman, Nate B. Phillips, Marco Schioppo, Nathan D. Lemke, Kyle P. Beloy, M Pizzocaro, Christopher W. Oates
Atomic clocks have been transformational in science and technology, leading to innovations such as global positioning, advanced communications, and tests of fundamental constant variation. Next-generation optical atomic clocks can extend the capability of

State-of-the-Art RF Signal Generation From Optical Frequency Division

September 2, 2013
Author(s)
Archita Hati, Craig W. Nelson, Corey A. Barnes, Danielle G. Lirette, Tara M. Fortier, Franklyn J. Quinlan, Jason A. DeSalvo, Andrew D. Ludlow, Till P. Rosenband, Scott A. Diddams, David A. Howe
We present the design of a novel, ultra-low phase-noise frequency synthesizer implemented with extremely low noise regenerative frequency dividers. This synthesizer generates eight outputs viz. 1.6 GHz, 320 MHz, 160 MHz, 80 MHz, 40 MHz, 20 MHz, 10 MHz and

Determination of the 5d6s 3D1 state lifetime and blackbody radiation clock shift in Yb

November 29, 2012
Author(s)
Kyle P. Beloy, Jeffrey A. Sherman, Nathan D. Lemke, Nathan M. Hinkley, Christopher W. Oates, Andrew D. Ludlow
The Stark shift of the ytterbium optical clock transition due to room temperature blackbody radiation is dominated by a static Stark effect, which was recently measured to high accuracy [J. A. Sherman et al., Phys. Rev. Lett. 108, 153002 (2012)]. However

Sub-femtosecond absolute timing jitter with a 10 GHz hybrid photonic-microwave oscillator

June 7, 2012
Author(s)
Tara M. Fortier, Craig W. Nelson, Archita Hati, Franklyn J. Quinlan, Jennifer A. Taylor, Haifeng (. Jiang, Chin-Wen Chou, Till P. Rosenband, Nathan D. Lemke, Andrew D. Ludlow, David A. Howe, Christopher W. Oates, Scott A. Diddams
We present an optical-electronic approach to generating microwave signals with high spectral purity. By overcoming shot noise and operating near fundamental thermal limits, we demonstrate 10 GHz signals that have timing deviation from an ideal periodic

A high stability optical frequency reference based on thermal calcium atoms

May 24, 2012
Author(s)
Richard W. Fox, Jeffrey Sherman, W. Douglas, Judith B. Olson, Andrew Ludlow, Christopher W. Oates
Here we report an imprecision below 10 -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 1S 0- 3P 1 intercombination line at 657 nm

A hybrid 10 GHz photonic-microwave oscillator with sub-femtosecond absolute timing jitter

May 24, 2012
Author(s)
Tara M. Fortier, Craig W. Nelson, Archita Hati, Franklyn J. Quinlan, Jennifer A. Taylor, Haifeng (. Jiang, Chin-Wen Chou, Nathan D. Lemke, Andrew D. Ludlow, David A. Howe, Christopher W. Oates, Scott A. Diddams
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

Blackbody effects in the Yb optical lattice clock

May 24, 2012
Author(s)
Andrew D. Ludlow, Jeffrey A. Sherman, Nathan D. Lemke, Kyle P. Beloy, Nathan M. Hinkley, M. Pizzocaro, Richard W. Fox, Christopher W. Oates
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 6s5d3D1

Ultra-low-noise Regenerative Frequency Divider for High Spectral Purity RF Signal Generation

May 24, 2012
Author(s)
Archita Hati, Craig W. Nelson, Corey A. Barnes, Danielle G. Lirette, Jason A. DeSalvo, Tara M. Fortier, Franklyn J. Quinlan, Andrew D. Ludlow, Till P. Rosenband, Scott A. Diddams, David A. Howe
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 dBc/Hz