Abstract

The intensity of light scattered by an air bubble in water is predicted by the geometric-optics calculation of Davis (1955) to have a divergent angular derivative as the critical scattering angle ϕ_c is approached. Effects of diffraction in the angular region near ϕ_c are described here. The Fraunhofer diffraction for scattering angles ϕ≤ϕ_c is estimated using a simplified physical-optics approximation. A ringing and decay of the far-field intensity is predicted that is formally similar to the near-field diffraction of a straight edge. Observation of millimeter radius bubbles in water with collimated monochromatic illumination confirm the existence of this ringing which has a quasi period ≃ 25 mrad. The diffraction calculation gives an approximate description of the relative ϕ of the observed maxima and minima. Fringes with a lower contrast and spacing ≃ 0.3 mrad were also observed; they appear to be caused by the interference of rays with distinct paths. Implications for the critical angle scattering of white light are discussed.

© 1979 Optical Society of America

Scattering by a bubble in water near the critical angle: interference effects

Philip L. Marston and Dwight L. Kingsbury
J. Opt. Soc. Am. 71(2) 192-196 (1981)

Critical angle light scattering from bubbles: an asymptotic series approximation

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Mie scattering near the critical angle of bubbles in water

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Critical-angle scattering of white light from a cylindrical bubble in glass: photographs of colors and computations

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J. Opt. Soc. Am. 73(12) 1658-1664 (1983)

Physical-optics approximation of near-critical-angle scattering by spheroidal bubbles

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