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Proceedings Paper

Performance of commercial laser diodes in fluorimetric detection
Author(s): C. Wersig; W. Finke; E. Handler; Hans-Peter Josel; Elmar Schmidt
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Paper Abstract

We have developed a compact and sensitive detection system based on the fluorescence excitation by commercial laser diodes in the VIS and NIR. The system comprises separate excitation, sample, and detection chambers and shows the potential of quantitatively determining immunological and other parameters with small and rugged instruments. Our examinations specifically addressed technical aspects of laser diodes which are responsible for the quality of fluorescence excitation, such as the characterization of the mode structure, the temperature and current dependency of the optical power emission, and the selection and adjustment of the laser wavelengths for optimal overlap with the fluorophors' absorption maxima (namely rhodamine 800, indocyanine green IR-125, and latex-bound dyes). Signal-to- noise level ratios of about 1:1 are reached at sub-nanomolar concentrations in an illuminated sample of 20 (mu) l using a standard photomultiplier tube in analog mode as the detector. Different arrangements of optical filters (e.g., interference, colored-glass type, and polarizing filters) have been optimized with regard to the excitation and detection paths. Furthermore, measures toward an internal calibration of the system have been investigated.

Paper Details

Date Published: 18 May 1993
PDF: 12 pages
Proc. SPIE 1885, Advances in Fluorescence Sensing Technology, (18 May 1993); doi: 10.1117/12.144725
Show Author Affiliations
C. Wersig, Boehringer Mannheim GmbH (Germany)
W. Finke, Boehringer Mannheim GmbH (Germany)
E. Handler, Boehringer Mannheim GmbH (Germany)
Hans-Peter Josel, Boehringer Mannheim GmbH (Germany)
Elmar Schmidt, Boehringer Mannheim GmbH (Germany)

Published in SPIE Proceedings Vol. 1885:
Advances in Fluorescence Sensing Technology
Joseph R. Lakowicz; Richard B. Thompson, Editor(s)

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