Laser modulation technique for single isotope spectroscopic studies - art.no. 041404

We demonstrate an atomic-beam approach to obtaining isotope specific driven -atom spectra using samples of arbitrary isotopic composition The method em ploys modulation of a target isotope ground-state population by an upstream preparation laser. Desired driven-atom signals generated downstream from t he preparation laser are isolated using a lock-in amplifier referenced to t he preparation laser modulation frequency. In our experiments, an intensity -modulated laser resonant with the barium (6s(2))S-1(o)-(6s6p)P-3(1), 791.1 -nm intercombination transition selectively pumps Ba-138 atoms via radiativ e decays to the (6s5d)D-3(1,2) metastable states. Dressed-atom gain studies using the (6s(2))S-1(o)-(6s6p)P-1(1) 553.5-nm transition demonstrate the e fficacy of the method. This technique has general utility for selectively i solating specific isotopic signals in systems possessing optically controll able atomic-beam populations.