title: High-sensitivity nonlinear spectroscopy using a frequency-offset pump.
abstract: We report the development of a simple method for eliminating coherent background noise and fluctuations from saturation-spectroscopy signals. With this technique, which we believe will also be effective in two-photon and other types of nonlinear spectroscopy, we have routinely observed background-free saturation signals in I2 at 514.5 nm with signal-to-noise ratios within an order of magnitude of the fundamental quantum limit.
authors.affiliation: Loborotoire de Physique des Lasers, Université Paris-Nord, 93430 Villetaneuse, France.
authors.forename: J J
authors.initials: JJ
authors.lastname: Snyder
authors.forename: R K
authors.initials: RK
authors.lastname: Raj
authors.forename: D
authors.initials: D
authors.lastname: Bloch
authors.forename: M
authors.initials: M
authors.lastname: Ducloy