Influence of internal scattering on the optical properties of particles and drops in the near infrared

A geometric optics approximation is used to compute the near-infrared absorption by particles containing internal scatterers, such as bubbles, occlusions, or other refractive-index inhomogeneities. If the probabilities of absorption and scattering are comparable, absorption by a weakly absorbing particle can be increased substantially beyond that in the absence of internal scattering. Although the geometric optics approach limits the range of applicability of the results, the effects are not necessarily restricted to particle dimensions and wavelengths where geometric optics is accurate.