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Proceedings Paper

High-resolution two-beam laser spectroscopy for live (motile) microscopic object detection and identification
Author(s): Victor S. Sobolev; A. M. Scherbachenko; G. A. Kashcheeva; E. N. Utkin; A. A. Stolpovsky; M. N. Prokopenko
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Paper Abstract

The results of analysis of statistical parameters are presented for the field scattered by a suspension of mobile microscopic objects at two laser beams sounding with frequency biasing of one of the beams. It is shown that a signal proportional to the intensity corresponds to the amplitude of a field scattered at one beam probing, and the spectrum of the field intensity follows the shape of the probability density of the projections of scattering particles velocity vectors onto the scattering vector. A new high-resolution spectrophotometer functional diagram is proposed, and results of experiments with Brownian particles and tests with alive and dead bacteria E-coli are discussed. A technique and algorithms of identification with small and large scattering angles are presented. It is shown that, according to the theory, the spectra of a signal from Brownian particles spherical in shape coincide well with Lorentzian curve, and the width of the curve is known to be determined by the diameters of particles. The spectra of tests with alive and dead bacteria at small scattering angles differ essentially in width; this may be a good criterion for the identification of samples. At great scattering angles, the widths of the spectra practically coincide. There are only small differences in the shape, which, at relevant handling of the spectra, also allow one to distinguish tests with alive and dead bacteria. The corresponding procedure and results of experimental tests are presented.

Paper Details

Date Published: 29 July 2002
PDF: 12 pages
Proc. SPIE 4900, Seventh International Symposium on Laser Metrology Applied to Science, Industry, and Everyday Life, (29 July 2002); doi: 10.1117/12.484504
Show Author Affiliations
Victor S. Sobolev, Institute of Automation and Electrometry (Russia)
A. M. Scherbachenko, Institute of Automation and Electrometry (Russia)
G. A. Kashcheeva, Institute of Automation and Electrometry (Russia)
E. N. Utkin, Institute of Automation and Electrometry (Russia)
A. A. Stolpovsky, Institute of Automation and Electrometry (Russia)
M. N. Prokopenko, Institute of Automation and Electrometry (Russia)


Published in SPIE Proceedings Vol. 4900:
Seventh International Symposium on Laser Metrology Applied to Science, Industry, and Everyday Life
Yuri V. Chugui; Sergei N. Bagayev; Albert Weckenmann; P. Herbert Osanna, Editor(s)

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