A four-beam optical polarimeter for robust particle shape detection

Particle shape detection and measurement are important features in the more general field of particle analysis and characterisation. Knowledge of the particle shape is useful in a wide variety of industrial applications. Although it is often practically feasible to use imaging technologies for particle shape analysis, this is not often a sufficiently efficient method for widespread on-line or in situ applications. In many applications it would be sufficient to have an indicator of particle shape, in the same way that a turbidity sensor is an indicator of the amount of particles present. Scattered polarized light from individual particles will be shown as a useful tool for particle shape detection. In principle, the presence of non-spherical particles can be diagnosed by analysing the change in polarisation state following scattering and in particular exploiting a configuration in which spherical particles produce no such changes. The concerns of this thesis are the design and implementation of optical polarimeters for the detection of non-spheres in an aqueous suspension, with particular emphasis on a robust implementation. [Continues.]