Optical properties of solids: Optical effects in solids occur in the wavelength range from the far infrared through the near ultraviolet. Dr. Tanner’s group studies materials by optical reflectance or transmittance over this entire range. Considerable time and effort has been spent to achieve coverage over a very broad spectral range (more than a factor of 104). The emphasis is on obtaining accurate reflectance values on small, often anisotropic, crystals, with analysis via Kramers-Kronig techniques to estimate the optical conductivity and dielectric function. The materials may be studied at temperatures down to that of liquid helium. Among the topics being studied are high-temperature superconductors, conducting polymers, and low-dimensional organic systems. Axion search: The axion search is a hypothetical elementary particle which is a candidate for the “dark matter” of the universe. With Pierre Sikivie and Neil Sullivan, Dr. Tanner contributed to the design and construction of a pilot axion detector, which operated at UF for two years. Many of its features are incorporated into a full-scale experiment, the Axion Dark Matter eXperiment (ADMX), at the University of Washington The Florida group contributes to the a high-resolution spectral analysis and in the upgrade with a dilution refrigerator to cool the cavity and SQUID amplifier recently installed in the experiment.