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

3 Scopus citations


Results on laser induced fluorescence (LIF) properties of collagen, cholesterol and chlorophyll a (chl a) when excited at 337.1 nm are reported. 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 (1 mM/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
EditorsTiina I. Karu, Anthony R. Young
Number of pages5
StatePublished - 1996
Externally publishedYes
EventEffects of Low-Power Light on Biological Systems - Barcelona, Spain
Duration: Sep 14 1995Sep 15 1995


OtherEffects of Low-Power Light on Biological Systems
CityBarcelona, Spain

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics


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