The atomic and molecular interactions at surfaces and interfaces determine the behaviour of an enormous variety of processes with both scientific and technological relevance. Understanding these interactions promises the ability to control and optimise the physical, chemical, electrical and optical properties of interfaces, allowing molecular engineering solutions technological challenges. Surface science is now a mature field and has given considerable insight into these interactions, but the majority of conventional instrumentation only allows the study of surfaces of solids in an ultra-high vacuum environment, a condition far removed from real-world applications. Purely optical techniques can be used bridge the "pressure gap" between the vacuum environment and the real world but optical spectroscopy is generally believed to be poorly suited to the characterisation of surfaces at the nanoscale. However, "epioptic" techniques have been developed in the last few years which have extremely good surface specificity, enabling the first in situ investigations in many fields.

In Edinburgh we are developing new epioptic instruments for surface characterisation. Applications include in situ monitoring of semiconductor micro and nanofabrication (in collaboration with the Dept. of Electronic and Electrical Engineering) and process control in liquid crystal device fabrication. In addition, by studying much simpler systems under well controlled conditions we are also trying to advance the theoretical understanding of the epioptics techniques themselves, which are currently rather poorly understood.