title: Comparison of scattering and reflection SFG: a question of phase-matching.
abstract: We present a comparison between sum frequency scattering (SFS) and reflection mode sum frequency generation (R-SFG). We have used scattering theory to describe both scattering experiments as well as reflection mode experiments. The interfacial vibrational spectrum of nanoscopic oil droplets dispersed in water was probed with SFS as well as with R-SFG. Spectra recorded in phase-matched R-SFG mode and spectra recorded with SFS from the same sample are different, which shows that different interfaces are measured. Scattering spectra at different scattering angles agree with nonlinear light scattering theory. We further present experiments with polymer films aimed at quantifying the comparative strength of R-SFG and SFS experiments.
authors.affiliation: Laboratory for fundamental BioPhotonics (LBP), Institute of Bio-engineering (IBI), School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland. sylvie.roke@epfl.ch.
authors.forename: Hilton B
authors.initials: HB
authors.lastname: de Aguiar
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Scheu
authors.forename: Kailash C
authors.initials: KC
authors.lastname: Jena
authors.forename: Alex G F
authors.initials: AG
authors.lastname: de Beer
authors.forename: Sylvie
authors.initials: S
authors.lastname: Roke