title: Optical frequency synthesizer for precision spectroscopy
abstract: We have used the frequency comb generated by a femtosecond mode-locked laser and broadened to more than an optical octave in a photonic crystal fiber to realize a frequency chain that links a 10 MHz radio frequency reference phase-coherently in one step to the optical region. By comparison with a similar frequency chain we set an upper limit for the uncertainty of this new approach to 5. 1x10(-16). This opens the door for measurement and synthesis of virtually any optical frequency and is ready to revolutionize frequency metrology.
authors.affiliation: Max-Planck-Institut fur Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany.
authors.initials: R
authors.lastname: Holzwarth
authors.initials: T
authors.lastname: Udem
authors.initials: TW
authors.lastname: Hansch
authors.initials: JC
authors.lastname: Knight
authors.initials: WJ
authors.lastname: Wadsworth
authors.initials: PS
authors.lastname: Russell