title: Imaging the Nonlinear Susceptibility Tensor of Collagen by Nonlinear Optical Stokes Ellipsometry.
abstract: Nonlinear optical Stokes ellipsometric (NOSE) microscopy was demonstrated for the analysis of collagen-rich biological tissues. NOSE is based on polarization-dependent second harmonic generation imaging. NOSE was used to access the molecular-level distribution of collagen fibril orientation relative to the local fiber axis at every position within the field of view. Fibril tilt-angle distribution was investigated by combining the NOSE measurements with ab initio calculations of the predicted molecular nonlinear optical response of a single collagen triple helix. The results were compared with results obtained previously by scanning electron microscopy, nuclear magnetic resonance imaging, and electron tomography. These results were enabled by first measuring the laboratory-frame Jones nonlinear susceptibility tensor, then extending to the local-frame tensor through pixel-by-pixel corrections based on local orientation.
authors.affiliation: Department of Chemistry, Purdue University, West Lafayette, Indiana.
authors.forename: Ximeng Y
authors.initials: XY
authors.lastname: Dow
authors.affiliation: Department of Chemistry, Purdue University, West Lafayette, Indiana.
authors.forename: Emma L
authors.initials: EL
authors.lastname: DeWalt
authors.affiliation: Department of Chemistry, Purdue University, West Lafayette, Indiana.
authors.forename: Shane Z
authors.initials: SZ
authors.lastname: Sullivan
authors.affiliation: Department of Chemistry, Purdue University, West Lafayette, Indiana.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Schmitt
authors.affiliation: Department of Chemistry, Purdue University, West Lafayette, Indiana.
authors.forename: James R W
authors.initials: JRW
authors.lastname: Ulcickas
authors.affiliation: Department of Chemistry, Purdue University, West Lafayette, Indiana. Electronic address: gsimpson@purdue.edu.
authors.forename: Garth J
authors.initials: GJ
authors.lastname: Simpson
mesh_terms: D000465:Algorithms; D000818:Animals; D003094:Collagen / Q000737:chemistry*; D004423:Ear; D004867:Equipment Design; D051379:Mice; D008859:Microscopy, Polarization / Q000295:instrumentation / Q000379:methods; D008956:Models, Chemical; D017711:Nonlinear Dynamics; D061848:Optical Imaging / Q000295:instrumentation / Q000379:methods; D017433:Protein Structure, Secondary; D011789:Quantum Theory; D012867:Skin / Q000737:chemistry / Q000648:ultrastructure; D013552:Swine; D013623:Tail / Q000737:chemistry / Q000648:ultrastructure
chemical_list: D003094:Collagen