Molecular beam deposition techniques have been used to generate dense optical thin films and film structures for studies which allow the assessment of the onset of laser damage effects, and which explore the control of microstructure. In the first study, ZnS films have been examined on germanium substrates by electron microscopy and the evidence available suggests that damage is initiated by laser beam interactions at dislocation loop clusters in the Ge surface. In the second study the feasibility of using stratified films to control microstructure has been assessed. Damage thresholds in (ZnS/ZnSe)_n are equivalent to those of uncoated substrates despite the incorporation of 100 or so separate interfaces. A wide range of coatings can be synthesized utilising such structures, which offer the potential of enhanced damage thresholds and broadband optical properties.