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Journal of Biomedical Optics • Open Access

Quantification of the second-order nonlinear susceptibility of collagen I using a laser scanning microscope
Author(s): Arne Erikson; Jonas Ortegren; Tord Hompland; Catharina de Lange Davies; Mikael Lindgren

Paper Abstract

Characteristic changes in the organization of fibrillar collagen can potentially serve as an early diagnostic marker in various pathological processes. Tissue types containing collagen I can be probed by pulsed high-intensity laser radiation, thereby generating second harmonic light that provides information about the composition and structure at a microscopic level. A technique was developed to determine the essential second harmonic generation (SHG) parameters in a laser scanning microscope setup. A rat-tail tendon frozen section was rotated in the xy-plane with the pulsed laser light propagating along the z-axis. By analyzing the generated second harmonic light in the forward direction with parallel and crossed polarizer relative to the polarization of the excitation laser beam, the second-order nonlinear optical susceptibilities of the collagen fiber were determined. Systematic variations in SHG response between ordered and less ordered structures were recorded and evaluated. A 500μm-thick z-cut lithiumniobate (LiNbO3) was used as reference. The method was applied on frozen sections of malignant melanoma and normal skin tissue. Significant differences were found in the values of d22, indicating that this parameter has a potential role in differentiating between normal and pathological processes.

Paper Details

Date Published: 1 July 2007
PDF: 10 pages
J. Biomed. Opt. 12(4) 044002 doi: 10.1117/1.2772311
Published in: Journal of Biomedical Optics Volume 12, Issue 4
Show Author Affiliations
Arne Erikson, Norwegian Univ. of Science and Technology (Norway)
Jonas Ortegren, Mid Sweden Univ. (Sweden)
Tord Hompland, Norwegian Univ. of Science and Technology (Norway)
Catharina de Lange Davies, Norwegian Univ. of Science and Technology (Norway)
Mikael Lindgren, Norges Teknisk-Naturvitenskapelige Univ. (Norway)

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