We have devised a simple new scheme to increase the isotopic selectivity in optical rare-isotope detection experiments. We can effectively remove interfering isotopes from an atomic beam by optically pumping them into a state that is invisible to the optical detection system. The selectivity of this resonant depletion scales exponentially with the isotope shift and yields almost unlimited selectivity in principle. We have demonstrated a selectivity of 2.3 × 105 with a single laser excitation in a beam of metastable krypton atoms. With better laser stability we may be able to improve the selectivity much further.
© 1989 Optical Society of America
G. R. Janik, B. A. Bushaw, and B. D. Cannon, "Resonant isotopic depletion spectroscopy," Opt. Lett. 14, 266-268 (1989)