Abstract
Rubidium 5S1/2-7S1/2 two-photon transition has been observed using a 760 nm external cavity diode laser and a vapor cell. With 10 mW laser power, the SNR and linewidth of the transition is 280 and 3 MHz, respectively. The ECDL is stabilized on the transition to an uncertainty of 7 kHz (2*10-11) using FM spectroscopy. Absolute frequencies of all hyperfine components in this transition have been measured to an uncertainty of 20 kHz using optical femtosecond comb. Different systematic effects are tabled. The uncertainty of hyper‾ne constant in rubidium 7S1/2 state is improved by a factor of four, comparing with previous best result. And for the first time, isotope shift of this transition is measured to be 131.567(73) MHz. By frequency doubling technique, a 1520 nm ECDL is stabilized on the two-photon transition. This provides a frequency standard in telecommunication band (1460-1530 nm, S-band).