Demonstrating optical saturation and velocity selection in rubidium vapor

Krishna Myneni

Vladimir A. Sautenkov, Sergey A. Saakyan, Andrey A. Bobrov +2 more

Wenlong Yang, M.M. Springer, Alexandre Kolomenski +2 more

Takahisa Mitsui Takahisa Mitsui, Hidetoshi Numata, Katsumi Sakurai

Doppler-free spectroscopy of high density atomic vapor has been demonstrated using copropagating pump-probe selective reflection. The observed narrow resonance has been interpreted theoretically taking account of the saturation of the atomic vapor. Our theory predicts that the saturation effect due to optical pumping is not uniform over the Doppler-broadened transition and is prominent at zero velocity.

D. Grischkowsky

Nataša Vujičić, Ticijana Ban, Gordana Kregar +2 more

We study resonantly enhanced cascaded two-photon transitions in Doppler-broadened rubidium vapor, induced by an optical frequency comb. Cascaded two-step excitation of atoms from the ground state 5$S$${}_{1/2}$ to the final 5$D$${}_{5/2}$ state via an intermediate 5$P$${}_{3/2}$ state as well as the influence of the frequency comb repetition rate on the two-photon fluorescence signal have been investigated. It is shown that the careful choice of ${f}_{R}$ leads to enhancement of the two-photon signal with considerable increase of the final $5{D}_{5/2}$-state population due to velocity-selective double resonance. Since the double-resonance condition for two different rubidium isotopes is fulfilled for different ${f}_{R}$, the possibility of isotope-selective two-photon excitation is explored. The dependence of the two-photon signal on external magnetic field values and different repetition rates of the optical frequency comb is also investigated.