JQI

The optical frequency comb is one of the most significant advances in laser physics since the
development of the laser itself. It has made routine the counting and synthesis of the oscillations
of light on the femtosecond time scale, and it is an essential component of all present and future
optical clocks and time-transfer systems. It further enables the most accurate measurement of any
fundamental physical quantity—that of the quantized energy states of atoms and ions with 18