title: Nonlinear plasmonics at planar metal surfaces.
abstract: We investigate the nonlinear optical response of a noble metal surface. We derive the components of the third-order nonlinear susceptibility and determine an absolute value of χ((3))≈0.2 nm(2) V(-2), a value that is more than two orders of magnitude larger than the values found for typical nonlinear laser crystals. Using nonlinear four-wave mixing (4WM) with incident laser pulses of frequencies ω(1) and ω(2), we generate fields oscillating at the nonlinear frequency ω(4WM)=2ω(1)-ω(2). We identify and discuss three distinct regimes: (i) a regime where the 4WM field is propagating, (ii) a regime where it is evanescent, and (iii) a regime where the nonlinear response couples to surface plasmon polaritons.
authors.affiliation: Institute of Optics, University of Rochester, Rochester, New York, NY 14620-4040, USA.
authors.forename: Stefano
authors.initials: S
authors.lastname: Palomba
authors.forename: Hayk
authors.initials: H
authors.lastname: Harutyunyan
authors.forename: Jan
authors.initials: J
authors.lastname: Renger
authors.forename: Romain
authors.initials: R
authors.lastname: Quidant
authors.forename: Niek F
authors.initials: NF
authors.lastname: van Hulst
authors.forename: Lukas
authors.initials: L
authors.lastname: Novotny