Mie scattering near the critical angle of bubbles in water

Mie-scattering algorithms were used to compute scattered intensities and phase differences for air bubbles in water. Results are plotted as a function of the scattering angle ϕ in the general range of 30–90° for size parameters ka of 25, 100, 1,000, and 10,000 (corresponding to radii a ≃ 1.3 μm to 0.8 mm). As ϕ decreases below the critical scattering angle at 82.8°, the intensity increases and undergoes broadly spaced oscillations that are described by a physical-optics approximation developed by the authors in a separate publication. Mie scattering also exhibits finely spaced oscillations.