United States Department of Defense
Document Type
Article
Date of this Version
2011
Abstract
This work describes the design and application of an apparatus to image aerosol
particles using digital holography in a flow-through, contact-free manner. Particles in an aerosol stream are illuminated by a triggered, pulsed laser and the pattern produced by the interference of this light with that scattered by the particles is recorded by a digital camera. The recorded pattern constitutes a digital hologram from which an image of the particles is computationally reconstructed using a fast Fourier transform. This imaging is validated using a cluster of ragweed pollen particles. Examples involving mineral-dust aerosols demonstrate the technique’s in situ imaging capability for complex-shaped particles over a size range of roughly 15–500 μm micrometers. The focusing-like character of the reconstruction process is demonstrated using a NaCl aerosol particle and is compared to a similar particle imaged with a conventional microscope.
Comments
Published in Journal of Quantitative Spectroscopy & Radiative Transfer, (2011),
doi:10.1016/j.jqsrt.2011.01.013