Summary Optical spectroscopy is a strong tool to probe and investigate molecules and materials. Using visible or infrared light science has been hugely successful in this, but we are missing equipment to study materials that has properties that lie 'in-between' the visible and infrared part of the spectrum. We are studying contrast agents used in diagnostics, materials used in telecommunication, and the fundamental science of rare-earth elements and coinage metals. All have properties that lie 'in-between', and we have been limited by the lack of tools to study this area: the 'in-between. In this project we will create a tool - a spectrometer - that specifically targets the 'in-between' and will allow us to use optical spectroscopy to probe and investigate all molecules and all materials.