Abstract
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 to the final 5 state via an intermediate 5 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 leads to enhancement of the two-photon signal with considerable increase of the final -state population due to velocity-selective double resonance. Since the double-resonance condition for two different rubidium isotopes is fulfilled for different , 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.
1 More- Received 7 November 2012
DOI:https://doi.org/10.1103/PhysRevA.87.013438
©2013 American Physical Society