title: Baryscan: a sensitive and user-friendly alternative to Z scan for weak nonlinearities measurements.
abstract: A new and efficient technique for measuring weak optical nonlinearities is reported. Like Z scan, its implementation is basic, both experimentally and theoretically, but leads to an improved sensitivity of λ/5.10⁴, which represents, to date, one of the highest observed enhancements. With this technique, which is based upon the use of a position sensitive detector, nonlinear properties are deduced by monitoring the barycentric position of a truncated pump-probe laser beam as the sample is moved along the optical axis. The technique is experimentally validated by measuring the pump-induced refractive index change and the underlying polarizability variation resulting from the excitation of the Cr(3+) ions in ruby.
authors.affiliation: Centre de recherche sur les Ions, les Matériaux et la Photonique (CIMAP), UMR 6252 Commissariat à l'Energie Atomique et aux Energies Alternatives, CNRS, Ecole Nationale Supérieure d'Ingénieurs de Caen, Université de Caen, 6 Boulevard du Maréchal Juin, 14050 Caen cedex 4, France. thomas.godin@ensicaen.fr
authors.forename: Thomas
authors.initials: T
authors.lastname: Godin
authors.forename: Michael
authors.initials: M
authors.lastname: Fromager
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Cagniot
authors.forename: Richard
authors.initials: R
authors.lastname: Moncorgé
authors.forename: Kamel
authors.initials: K
authors.lastname: Aït-Ameur