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Optical Frequency Measurements Group


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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 approaching 10-16. 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, mid-IR molecular spectroscopy, optical waveform generation,and calibration of astronomical spectrographs for searches for exo-planets. Micro-resonators are being investigated as a promising platform to move frequency combs from laboratory devices to chip-integrated devices for science and metrology.


Frequency Comb Calibration of Astronomical Spectrographs—We have constructed portable frequency combs that have provided in situ calibration of astronomical spectrographs, to aid in the search for exo-planets.

Frequency Comb Spectroscopy—We use frequency combs based on ultrafast mode-locked lasers to perform precision spectroscopy in the near- and mid-infrared domains, for rapid, high-sensitivity, broadband gas detection. 

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 goal is to understand the fundamental …

Femtosecond Laser Frequency Combs for Optical Clocks—We develop self-referenced mode-locked femtosecond lasers that function as the "gears" of optical clocks. The femtosecond laser clockwork is capable of phase-coherently linking optical frequencies …

Yb Lattice Clock—Our Group is developing high stability, high accuracy optical atomic clocks based on thousands of Yb atoms confined to an optical lattice. Such clocks will find applications in tests of fundamental …

Calcium Optical Beam Clock—A simple, compact alternative to the highest performing optical standards, the Ca clock uses a thermal beam of neutral atoms with one or two lasers to achieve high stability in a potentially …

Optical Cavities for Laser Stabilization—Optical cavities are essential elements of optical atomic clocks, as they serve to pre-stabilize the clock laser. Our Group is currently developing state-of-the-art cavities to reduce the …

Optical and Microwave Waveform Synthesis—We use femtosecond-laser frequency combs to generate optical and microwave waveforms with unprecedented noise performance.  


Time and Frequency Division
National Institute of Standards and Technology
Mail Stop 847.10
325 Broadway
Boulder, CO 80305-3334

Name Position Phone
Scott Diddams NIST Fellow 303-497-7459
Tara Fortier Project Leader 303-497-4686
Richard Fox Project Leader 303-497-3478
Andrew Ludlow Project Leader 303-497-4972
Chris Oates Group Leader 303-497-7654
Scott Papp Project Leader 303-497-3822
Franklyn Quinlan Project Leader 303-497-4580

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).

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.