Laser-induced fluorescence studies on collagen, cholesterol, and chlorophyll a

Mihail L. Pascu, N. Moise, Sebastian Wachsmann-Hogiu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Results on laser induced fluorescence (LIF) properties of collagen, cholesterol, and chlorophyll a (chl a) are reported, when excited at 337.1 nm. The collagen and cholesterol fluorescence was studied in connection with atherosclerotic plaques diagnostics and/or removal within the cardiovascular system. The fluorescence signal excitation and collection were made using optical fibers, for liquid samples at concentrations between 0.1 mg/ml and 5.0 mg/ml for both collagen and cholesterol, their fluorescence lifetime being 5 nsec and 6 nsec, respectively. CHl a LIF concerned the stimulated emission of radiation considering the pigment as laser active medium. Chl a concentrations varied, in different solvents between 5 multiplied by 10 -3 M/l and 10 -5 M/l. For chl a at 0.62 mM/l and pumping photon densities higher than 5 multiplied by 10 16 photons/cm 2 and pulse, fluorescence linewidth narrowing from 28 nm to 5 nm in ethanol and from 25 nm to 4 nm in DMSO were obtained. Lasing maxima at 672 nm in acetone, 674 nm in ethanol and 678 nm in DMSO were observed. At lasing conditions for chl a in DMSO (1mM/l) the measured fluorescence lifetime was 2 nsec instead of 5 nsec for normal fluorescence. The results on chl a stimulated emission show a lower lasing threshold at 10 16 photons/cm 2 and pulse, than previously reported, if DMSO solvent is used.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsRinaldo Cubeddu, Serge R. Mordon, Katarina Svanberg
Pages216-220
Number of pages5
Volume2627
StatePublished - 1995
Externally publishedYes
EventOptical Biopsies - Barcelona, Spain
Duration: Sep 14 1995Sep 15 1995

Other

OtherOptical Biopsies
CityBarcelona, Spain
Period9/14/959/15/95

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

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    Pascu, M. L., Moise, N., & Wachsmann-Hogiu, S. (1995). Laser-induced fluorescence studies on collagen, cholesterol, and chlorophyll a. In R. Cubeddu, S. R. Mordon, & K. Svanberg (Eds.), Proceedings of SPIE - The International Society for Optical Engineering (Vol. 2627, pp. 216-220)