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Proceedings Paper

Two-dimensional angular optical scattering patterns of aerosol particles in the mid-infrared: measurements designed to obtain particle absorption
Author(s): Kevin B Aptowicz; Yong-Le Pan; Ronald G. Pinnick; Steven C. Hill; Richard L. Tober; Richard K. Chang; Burt V. Bronk
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Paper Abstract

Real-time and in-situ detection and discrimination of aerosol particles, especially bio-aerosols, continues to be an important challenge. The technique labeled TAOS (Two-dimensional Angular Optical Scattering) characterizes particles based upon the angular distribution of elastically scattered light. The detected angular distribution of light, labeled the TAOS pattern, depends upon the particle’s shape, size, surface features, and its complex refractive index. Thus, the absorptive properties of a particle affect the TAOS pattern. Furthermore, we expect to use this change in the TAOS pattern, which occurs when the particle absorption band includes the input wavelength, to characterize the strength of the absorption. Thus, by illuminating a particle in the mid-infrared wavelength range, high frequency vibrational modes that are unique to the aerosol can be reached and quantified. Spherical aerosol particles (in the diameter range of 50-60 micrometers) were generated via a droplet generator and illuminated by an Interband Cascade (IC) laser designed to emit in the 3-5 micrometers wavelength range. The TAOS pattern of the elastically scattered light was detected with an InSb-focal-plane-array infrared camera.

Paper Details

Date Published: 8 March 2004
PDF: 4 pages
Proc. SPIE 5269, Chemical and Biological Point Sensors for Homeland Defense, (8 March 2004); doi: 10.1117/12.518873
Show Author Affiliations
Kevin B Aptowicz, Yale Univ. (United States)
Yong-Le Pan, Yale Univ. (United States)
Ronald G. Pinnick, Army Research Lab. (United States)
Steven C. Hill, Army Research Lab. (United States)
Richard L. Tober, Army Research Lab. (United States)
Richard K. Chang, Yale Univ. (United States)
Burt V. Bronk, Air Force Research Lab. (United States)

Published in SPIE Proceedings Vol. 5269:
Chemical and Biological Point Sensors for Homeland Defense
Arthur J. Sedlacek III; Richard Colton; Tuan Vo-Dinh, Editor(s)

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