The frequency comb setup for absolute frequency metrology experiments
The frequency comb facility allows optical precision frequency measurements with an accuracy (at the moment) of 12 digits. Two single mode fibers link the frequency combs with other labs for remote measurement of laser frequencies. There are two types of frequency comb lasers available for this purpose. One is based on a home-built Ti:sapphire modelocked laser. It can operate from 700 nm - 900 nm (and from 350 nm to 450 nm with freequency doubling), and has a tunable repetition rate between 70 MHz - 300 MHz. The other system is a commercial (Menlo-systems) one based on Er-fiber technology. It operates at a repetition rate of 250 MHz. With this system precision calibration can take place from 550 - 2000 nm. Both frequency comb lasers are locked to a Rubidium atomic clock, which itself is locked to the GPS system for long term stability and accuracy.
Below is a picture of the commercial Er-fiber frequency comb laser.
Contact Person at LaserLaB: Kjeld Eikema, email: firstname.lastname@example.org