This research involves the study of the optical transmission properties of high temperature superconductors, using free standing ultrathin single crystals and the exceptionally bright infrared radiation available at the National Synchrotron Light Source at Brookhaven. A major part of the research will be devoted to sample preparation and characterization, including structural and transport measurements carried out at Stony Brook. The objectives of the present investigation are to elucidate the nature of the superconducting energy gap in these compounds, and to study the optically active elementary excitations in the normal and superconducting states. The optical reflectivity of these materials is unusual and complex and transmission studies have an inherent advantage of better accuracy at low frequencies. Materials with magnetic and non-magnetic dopants, with irradiation induced defects, and with various level of oxygen deficiency will be prepared and investigated. Studies will also be made of reference samples of conventional superconductors and quasi two- dimensional metals.
