Light Scattering by Bubbles in Liquids and Applications to Physical Acoustics

Abstract

This paper is concerned with the basic optical properties of bubbles in liquids. An understanding of the scattering of light by bubbles is important for the proper application of optical methods for monitoring the dynamics of bubbles and also for the use and interpretation of high speed imaging technologies. Furthermore, various optical methods are feasible for modifying the dynamics of bubbles. The approach taken in the present paper may appear to be somewhat “introductory” or “old fashion” to some readers since at least in the case of spherical bubbles, the results of Mie theory may be trivially numerically evaluated using modern algorithms [1]. The needed understanding of scattering processes, however, involves different lines of reasoning than the numerical evaluation of Mie’s partialwave series for the range of sizes typically encountered in bubble dynamics research. In motivating a related review of scattering processes, Nussenzveig [2] gives the following quote attributed to E. P. Wigner “It is nice to know that the computer understands the problem, but I would like to understand it too.” It seems also appropriate to note that van de Hulst’s highly influential monograph on light scattering [3] draws heavily on reasoning worked out without significant computational aids in his thesis.