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Optical Frequency Measurements Group

The Optical Frequency Measurements Group conducts cutting-edge research focused on generating stable optical frequencies and developing tools for precisely measuring optical frequencies, which have the potential to achieve unprecedented timing performance.

We construct different types of atomic clocks to generate optical frequencies that have demonstrated a fractional instability approaching 1 part in 1018 and an absolute fractional frequency uncertainty below 10-17. We develop laser frequency combs to connect stable optical frequencies to each other and to microwave sources with an imprecision below 1 part in 1019. These state-of-the-art frequency combs are also developed for other important applications, including ultra-low noise microwave generation, chip-scale sensors, mid-IR molecular spectroscopy, optical waveform generation,and calibration of astronomical spectrographs for searches for exo-planets.

News and Updates

Projects and Programs

Microresonator Device Research

With micro-resonators (fabricated in house or by collaborators) we are developing microcombs, integrated reference cavities and low-noise laser sources. The

Publications

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

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

First observation with global network of optical atomic clocks aimed for a dark matter detection

Author(s)
P. Wcislo, P. Ablewski, Kyle P. Beloy, S. Bilicki, M. Bober, Roger C. Brown, Robert J. Fasano, R. Ciurylo, H. Hachisu, T. Ido, J. Lodewyck, Andrew D. Ludlow, William F. McGrew, P. Morzynski, Daniele Nicolodi, Marco Schioppo, M. Sekido, R. Le Targat, P. Wolf, Xiaogang Zhang, B. Zjawin, M. Zawada
We report on the first earth-scale quantum sensor network based on optical atomic clocks aimed at dark matter (DM) detection. Exploiting differences in the

Atomic clock performance beyond Earth’s gravitational limit

Author(s)
William F. McGrew, Xiaogang Zhang, Robert J. Fasano, Stefan A. Schaeffer, Kyle P. Beloy, Daniele Nicolodi, Roger C. Brown, N. Hinkley, G. Milani, Marco Schioppo, T. H. Yoon, Andrew D. Ludlow
The passage of time is tracked by counting oscillations of a suitable frequency reference (e.g., the number of revolutions of Earth around the sun or the number

Awards

2019 PECASE - Franklyn Quinlan

The Presidential Early Career Award for Scientists and Engineers (PECASE) is the highest honor bestowed by the United States Government to...

2017 Rabi Award - Scott Diddams

The Rabi Award is to recognize outstanding contributions related to the fields of atomic and molecular frequency standards, and time...

2016 PECASE - Andrew Ludlow

The Presidential Early Career Awards for Scientists and Engineers (PECASE) represent the highest honor bestowed by the United States...

2008 APS Fellow - Scott Diddams

The criterion for election is exceptional contributions to the physics enterprise; e.g., outstanding physics research, important...

NRC Postdoc Program

Apply for an NRC postdoc in optical atomic clock or fs-laser frequency comb research. Application deadlines are February 1 and August 1 annually (but inquire well in advance).

Postdoc and Student Opportunities

Summer Undergraduate Research Fellowship (SURF): Summer program at NIST-Boulder for undergraduates in science, engineering, and mathematics. The application deadline is February 15 annually.

Postdoctoral, Visiting Scientist, and Graduate Positions: Our group has periodic openings for Postdoctoral Fellows, Visiting Scientists, and Graduate Students. Please contact us for more information.

Contacts

Group Leader

Project Leaders