A Fourier Transform spectrometer consists of a Michelson interferometer with a moveable mirror and a broadband source. An interference pattern is obtained at each position of the mirror, and these ‘interferograms’ are combined and a Fourier transform calculated to retrieve the absorption at each wavelength. The technique is a rapid and efficient method for measuring the absorption spectra of samples, and can be used for both solid state structures and pharmaceutical samples. The DC Field Facility has installed a Bruker Vertex 80V Fourier transform infrared spectrometer for Infrared spectroscopy measurements at variable temperatures, 2K-300K, and high magnetic fields up to 35T. Absorption mechanisms associated with various excitations and collective modes in solids (phonons, electrons, spins,...) give rise to additive contributions to optical spectra and thus can be directly revealed through optical experiments.