Optical Frequency Measurements Using fs- Comb Generators

摘要

We have used a Ti:Sapphire-based fs-comb generator to measure the frequencies of several optical frequency standards available at PTB. The frequency values for HeNe- and frequency-doubled Nd:Yag lasers stabilzed to Iodine hyperfine transitions as well as the frequencies of the ~(1)S_(0)-~(3)P_(1) transition of ~(40)Ca at 657.5 nm (456 THz) and the ~(2)S_(1/2)-~(2)D_(3/2) transition of ~(171)Yb~(+) at 435.5 nm (688 THz) are presented. Comparing our results with previously published data for the frequency variation of transitions of the Hg~(+) ion and H atom, we have derived a new upper limit of the variation of the fine structure constant α.