Femtosecond Metrology

Dr. Thomas Udem

Max Planck Institute for Quantum Optics, Garching


The properties of the regular spaced cavity modes of mode locked  lasers are reviewed. It is shown that these so called frequency combs can be used to measure the frequency of visible light  with unprecented precission. Applications like the precise determination of the Rydberg constant and the Lamb shift along with fundamental tests of the frequency comb technique are discussed. The same technology that has allowed to stabilize the frequency comb also allows to fix the phase between the carrier wave and the pulse envelope.