Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Optical Frequency Combs: From Frequency Metrology to Optical Phase Control



Jun Ye, H Schnatz, Leo W. Hollberg


A remarkable synergy between traditionally CW laser-based precision optical frequency metrology and mode-locked ultrafast lasers has led to precision control of the frequency spectrum produced by mode-locked lasers. Such a phase - controlled mode-locked laser forms the basis of a femtosecond optical frequency comb generator with a regular comb of sharp lines with well-defined frequencies. For a comb with sufficiently broad bandwidth, it has become straightforward to determine the absolute frequencies of all of the comb lines. This ability has revolutionized optical frequency metrology and synthesis. It has also served as the basis for the recent demonstrations of optical atomic clocks that utilize optical frequency transitions. Precision femtosecond optical frequency comb also has a major impact on time-domain applications, including carrier-envelope phase stabilization, synthesis of a single pulse from two independent lasers, nonlinear spectroscopy, and passive amplifiers based on empty external optical cavities. In this article, we first review the frequency domain description of mode-locked laser and the connection between the carrier-envelope phase and the frequency spectrum to provide a basis for understanding how the absolute frequencies can be determined and controlled. Using this understanding, applications in optical frequency metrology and synthesis and optical atomic clocks are discussed. This is followed by a discussion on time domain experiments.
IEEE Journal of Selected Topics in Quantum Electronics


femtosecond optical comb


Ye, J. , Schnatz, H. and Hollberg, L. (2008), Optical Frequency Combs: From Frequency Metrology to Optical Phase Control, IEEE Journal of Selected Topics in Quantum Electronics (Accessed May 18, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created October 16, 2008