Abstract:
Energy in the form of electromagnetic radiation is one of the major probes in the study of the fundamental structure of matter. The development of experiments and theory of the optical properties of solids has been synchronous with the development of solid-state physics. The answer to the question "What actually happens when light is shone on a metal?" is by no means a complete one, and current approaches date only from the mid-fifties onwards. Assumptions in the theory and technical difficulties in obtaining accurate data are the main stumbling blocks at present.
