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Proceedings Paper

Multispectral diode laser based shifted excitation Raman difference spectroscopy for biological sample identification
Author(s): Kay Sowoidnich; Heinz-Detlef Kronfeldt
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Paper Abstract

Raman spectroscopy is a well established analytical method with applications in many areas, e.g. analysis of biological samples. To overcome the problem of an undesired fluorescence background masking the Raman signals we present a multi-spectral approach using shifted excitation Raman difference spectroscopy (SERDS). For our investigations we applied microsystem diode lasers which realize two slightly shifted excitation wavelengths required to perform SERDS at 488 nm, 671 nm, and 785 nm. The emission at 488 nm with an optical power of up to 30 mW and a spectral shift of 0.3 nm (12 cm-1) is realized by frequency doubling of a 976 nm distributed feedback (DFB) diode laser. The 671 nm laser diode contains two separate laser cavities (spectral shift: 0.7 nm (13 cm-1)) each incorporating a volume Bragg grating as frequency selective element. In that case, optical powers up to 50 mW can be obtained. For investigations at 785 nm we used a DFB laser with a maximum optical power of 110 mW and a spectral shift of 0.5 nm (7 cm-1). Meat, fat tissue, connective tissue and bones from pork and beef were used as test samples to demonstrate the effective background removal using SERDS. For all three wavelengths integration times of only 5 - 10 seconds were necessary showing the possibility of SERDS for rapid sample identification. A comparison with conventional Raman spectra is given pointing out the improvement of spectral quality. The applicability of SERDS for other analytical applications, e.g. medical diagnosis will be discussed.

Paper Details

Date Published: 9 May 2012
PDF: 8 pages
Proc. SPIE 8366, Advanced Environmental, Chemical, and Biological Sensing Technologies IX, 836603 (9 May 2012); doi: 10.1117/12.918253
Show Author Affiliations
Kay Sowoidnich, Technische Univ. Berlin (Germany)
Heinz-Detlef Kronfeldt, Technische Univ. Berlin (Germany)

Published in SPIE Proceedings Vol. 8366:
Advanced Environmental, Chemical, and Biological Sensing Technologies IX
Tuan Vo-Dinh; Robert A. Lieberman; Günter Gauglitz, Editor(s)

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