Direct two-photon resonant excitation and absolute frequency measurement of cesium transitions using a femtosecond comb

We measure the optical transition frequencies of the 6s 2S1/2 rarr 8s 2S1/2, 9s 2S1/2, and 7d 2D3/2,5/2 transitions in a 133Cs vapor cell, with an uncertainty < 100 kHz using a femtosecond laser frequency comb.