High Speed Nonlinear Interferometric Vibrational Analysis of Lipids by Spectral Decomposition

摘要

Unlike other CARS-based (coherent anti-Stokes Ramannscattering) spectroscopy techniques, nonlinear interfero-nmetric vibrational spectroscopy (NIVS) is linear in analytenconcentration and has a Raman line shape free of non-nresonant background distortions. We use spontaneousnRaman scattering as a high accuracy benchmark for NIVS.nAs a challenging comparison, we examine spectra in thenCH stretching region of six lipid samples. Singular valuendecomposition and reference to an independent chemicalnassay are used to directly compare NIVS and spontaneousnRaman scattering. We demonstrate that NIVS can deter-nmine the relative degree of unsaturation in six differentnlipid samples as accurately as spontaneous Raman spec-ntroscopy, but 200 times faster. A skin tissue sample isnmapped out to demonstrate quantitative lipid proteinndifferentiation with spatial resolution.