Dust Polarisation in the Interstellar Medium

The optical to submillimetre continuum radiation of the ISM is polarised by aligned non-spherical dust particles. Modelling of this polarisation spectrum in combination with abundance constraints and simultaneous fit to extinction and emission yields important information on dust grains, including chemistry, mineralogy, particle sizes, and shapes. The pristine nature of dust is better revealed by studying sight-lines that include a single-cloud in the observing beam as compared to attempts at analysing averages of the observing characteristics over multiple-clouds. The propagation of polarised light through dust enshrouded objects is solved by polarisation radiative transfer for which we outline the central methodology.