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Optical Frequency Combs: Coherently Uniting the Electromagnetic Spectrum



Scott Diddams, Kerry J. Vahala, Thomas Udem


Optical frequency combs were introduced around 20 years ago as a laser technology that could synthesize and count the ultrafast rate of the oscillating cycles of light. Functioning in a manner analogous to a clockwork of gears, the frequency comb phase-coherently upconverts a radio frequency signal by a factor of ≈10^5 to provide a vast array of evenly spaced optical frequencies, which is the comb for which the device is named. It also divides an optical frequency down to a radio frequency, or translates its phase to any other optical frequency across hundreds of terahertz of bandwidth. We review the historical backdrop against which this powerful tool for coherently uniting the electromagnetic spectrum developed. Advances in frequency comb functionality, physical implementation, and application are also described.
Science Magazine


Frequency Comb, Frequency Metrology, Optical Clock


Diddams, S. , Vahala, K. and Udem, T. (2020), Optical Frequency Combs: Coherently Uniting the Electromagnetic Spectrum, Science Magazine, [online], (Accessed June 21, 2024)


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Created July 17, 2020, Updated February 27, 2022