title: High speed nonlinear interferometric vibrational analysis of lipids by spectral decomposition.
abstract: Unlike other CARS-based (coherent anti-Stokes Raman scattering) spectroscopy techniques, nonlinear interferometric vibrational spectroscopy (NIVS) is linear in analyte concentration and has a Raman line shape free of nonresonant background distortions. We use spontaneous Raman scattering as a high accuracy benchmark for NIVS. As a challenging comparison, we examine spectra in the CH stretching region of six lipid samples. Singular value decomposition and reference to an independent chemical assay are used to directly compare NIVS and spontaneous Raman scattering. We demonstrate that NIVS can determine the relative degree of unsaturation in six different lipid samples as accurately as spontaneous Raman spectroscopy, but 200 times faster. A skin tissue sample is mapped out to demonstrate quantitative lipid-protein differentiation with spatial resolution.
authors.affiliation: Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Praveen D
authors.initials: PD
authors.lastname: Chowdary
authors.forename: Wladimir A
authors.initials: WA
authors.lastname: Benalcazar
authors.forename: Zhi
authors.initials: Z
authors.lastname: Jiang
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Marks
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Boppart
authors.forename: Martin
authors.initials: M
authors.lastname: Gruebele
mesh_terms: D007368:Interferometry / Q000379:methods; D008055:Lipids / Q000032:analysis* / Q000737:chemistry; D010938:Plant Oils / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D013997:Time Factors; D014732:Vibration
chemical_list: D008055:Lipids; D010938:Plant Oils