Laser light deformation of microdroplets

Abstract

This masters work describes the deformation of a droplet that is illuminated by a laser beam. The theory for linear fluid mechanical motion of the droplet is discussed. This is combined with Lorenz-Mie scattering. Droplet deformations resulting from the optical radiation pressure are computed.

Specific beam profiles are discussed in the literature for the purposes of optical droplet deformation, namely the cases of linear and circular polarized plane waves, a Gaussian beam and the Bessel beam. The general case of an arbitrary beam is not, to the author's knowledge, given in the published literature. Such a framework is developed from first principles and presented in this work.

A Mathematica script was written to compute deformations. These are calculated, fitting nicely to those found by Ellingsen in a recent article. The case of two plane waves from opposite directions is discussed here for the first time, and droplet shapes produced.

The size droplets considered is between the geometrical limit and the Rayleigh limit. The numerical load increases quickly with increasing values of the droplet radius and wave vector. The hardest to compute coefficients die off the most quickly with time.