Journal of the Optical Society of America A: Optics Image Science and Vision
The extinction efficiency for the interaction of a plane wave with a large nonabsorbing spherical particle is approximately 2.0. When a Gaussian beam of half-width w(0) is incident upon a spherical particle of radius a with w(o)/a < 1, the extinction efficiency attains unexpectedly high or low values, contrary to intuitive expectations. The reason for this is associated with the so-called compensating term in the scattered field, which cancels the field of the Gaussian beam behind the particle, thereby producing the particle's shadow. I introduce a decomposition of the total exterior field into incoming and outgoing portions that are free of compensating terms. It is then shown that a suitably defined interaction efficiency has the intuitively expected asymptotic values of 2.0 for w(o)/a >> 1 and 1.0 for w(o)/a << 1.
Lock, James A., "Interpretation of Extinction in Gaussian-Beam Scattering" (1995). Physics Faculty Publications. 85.
Lock, James A. "Interpretation of Extinction in Gaussian-Beam Scattering." Journal of the Optical Society of America A: Optics Image Science and Vision 12 (1995): 929-938.
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