title: Molecular orientational order probed by coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) microscopy: a spectral comparative study.
abstract: We investigate how to extract information on the orientational order of molecular bonds in biological samples from polarized coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) microscopy. Experimentally, the mean orientation of the molecular angular distribution, as well as its second and fourth orders of symmetry, are estimated by monitoring intensity signals under a varying incident polarization. We provide a generic method of analysis of polarized signals in both CARS and SRS contrasts, and apply it to imaging of lipid bonds' orientational order in multilamellar vesicles. A comparison of the two contrasts in the lipid region around 3000 cm(-1) shows that while SRS allows retrieving pure molecular order information, CARS is generally tainted by a bias from the nonresonant contribution.
authors.affiliation: Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel , UMR 7249, 13013 Marseille, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Duboisset
authors.forename: Pascal
authors.initials: P
authors.lastname: Berto
authors.forename: Paulina
authors.initials: P
authors.lastname: Gasecka
authors.forename: Fatma-Zohra
authors.initials: FZ
authors.lastname: Bioud
authors.forename: Patrick
authors.initials: P
authors.lastname: Ferrand
authors.forename: Hervé
authors.initials: H
authors.lastname: Rigneault
authors.forename: Sophie
authors.initials: S
authors.lastname: Brasselet
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000031:analogs & derivatives / Q000737:chemistry; D008567:Membranes, Artificial; D008853:Microscopy / Q000379:methods*; D017711:Nonlinear Dynamics; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D008567:Membranes, Artificial; D015060:1,2-Dipalmitoylphosphatidylcholine; C081581:colfosceril palmitate