Ambrose Swasey Professor of Physics
Rockefeller Building 225D
B.S., The Ohio State University (1975)
Ph.D., University of Pennsylvania (1981)
Modern Optics and Condensed Matter Experiment; Nonlinear Optics
Organic, or carbon containing materials, are the basis of life, due in large part to the enormous number of ways that atoms in organic molecules can arrange themselves. This variety of structure leads to a corresponding variety in function, leading, for example, to the amazing activities of living things. One can then speculate that the variety of structures and functions in organic molecules can be harnessed to advantage in new generations of electronic and photonic devices that find application in information technology. Indeed, physicists, chemists, and engineers can collaborate to produce designer materials for a variety of functions, and this, in fact, is the focus of work of our research group. In addition to their molecular structure and function variability, organic materials also can be formed in a number of fascinating arrangements and states of matter. Molecules can link together to form polymers, they spontaneously organize themselves into crystals and liquid crystals, and they can assemble into layers the thickness of a single molecular layer. Structure formation is also controllable.
Members of our research group measure optical, electronic, and structural properties of organic electronic and photonic materials with the aim of gaining an understanding of the physical origin of optical and electronic properties, as well as the potential of particular materials for optoelectronic devices. This knowledge is then applied in collaboration with chemists to design improvements in materials. We are interested in the electronic structure of organic materials, and study features such as the range and nature of delocalized charge, as well as how molecular symmetry and dimensionality determine electronic and optical properties and the nature of elementary excitations. We also study how these materials might be used in devices, such as solar cells, lasers, displays, optical switches, image processors, and other electronic and optical devices. Much of our work is focused on nonlinear optical properties exhibited in a number of phenomena such as harmonic generation, optical control, and image processing, all resulting from the interaction of intense lasers with these materials. We are also interested in electronic transport in organic materials, and study all of these properties in polymers, liquid crystals, molecular thickness films, and in self-organizing, molecular and nanoscale composite materials.
Our laboratory is equipped with the latest equipment for measuring these properties, including ultrafast Ti:Sapphire laser systems, a tunable picosecond laser, tunable nanosecond lasers, as well as associated detection and data acquisition techniques. Members of our research group, including research associates, high school, undergraduate, and graduate students master these techniques, as well as others available in our laboratory and across campus. Other facilities our group uses include nanoscale equipment including an atomic force microscope and a near-field scanning optical microscope. In addition, group members learn how to fabricate samples in the physics department’s materials fabrication facility, and use associated analytical equipment. Current projects include polymeric one and two dimensional photonic crystals, dynamic holography, nonlinear optics in chiral media, liquid crystalline semiconductors, and near-field microscopy.