Rapid electro-optic control of the carrier-envelope-offset frequency for ultra-low noise frequency combs

We report on a novel electro-optic modulator that acts on the carrier-envelope-offset frequency of a femtosecond pulsed laser with negligible cross-talk to the position of the optical carrier modes. The fast response on the nanosecond time scale allows to stabilize the carrier-envelope-offset frequency with a bandwidth in excess of 1 MHz while not perturbing a potential independent stabilization of a carrier mode to an optical reference. Out-of-loop verification of both optical and CEO frequency suggests a sub-Hz stability for all (partially virtual) spectral comb lines between 0 Hz and 400 THz.