title: Comparison of 87Rb N-resonances for D1 and D2 transitions.
abstract: We report an experimental comparison of three-photon-absorption resonances (N-resonances) for the D1 and D2 optical transitions of thermal (87)Rb vapor. We find that the D2 N-resonance has better contrast, a broader linewidth, and a more symmetric line shape than the D1 N-resonance. Taken together, these factors imply superior performance for frequency standards operating on alkali D2 N-resonances, in contrast with coherent population trapping resonances, for which the D2 transition provides poorer frequency standard performance than the D1 transition.
authors.affiliation: Harvard-Smithsonian Center for Astrophysics and Department of Physics, Harvard University, Cambridge, Massachusettes 02138, USA. inovikova@cfa.harvard.edu
authors.forename: Irina
authors.initials: I
authors.lastname: Novikova
authors.forename: David F
authors.initials: DF
authors.lastname: Phillips
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Zibrov
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Walsworth
authors.forename: Aleksei V
authors.initials: AV
authors.lastname: Taichenachev
authors.forename: Valeriy I
authors.initials: VI
authors.lastname: Yudin