Terahertz spectroscopy has emerged as a powerful tool for studies of condensed matter systems, complementary to other more widespread techniques such as x-ray diffraction or infrared spectroscopy. The use of terahertz radiation, lying in the spectral range 0.1-10 THz (3-330 cm^{-1}), can reveal structural and dynamical information that is not easily accessible by other means.Terahertz vibrational modes are often mediators of technologically important chemical reactions such as the gas capture reaction in clathrates or exchange reactions in metal-organic frameworks. This presentation will review several spectroscopic studies which illustrate some of the ways in which terahertz spectroscopy is being used to study such soft materials.

Bio:
Dr. Mittleman received his B.S. in physics from the Massachusetts Institute of Technology in 1988, and his M.S. in 1990 and Ph.D. in 1994, both in physics from the University of California, Berkeley. He then joined AT&T Bell Laboratories as a post-doctoral member of the technical staff, where he built one of the early terahertz time-domain spectrometers for material spectroscopy and imaging. Dr. Mittleman joined the ECE Department at Rice University in September 1996. In 2015, he moved to the School of Engineering at Brown University. His research interests involve the science and technology of terahertz radiation. He is a Fellow of the OSA, the APS, and the IEEE, and a Humboldt Research Award winner, and in 2023-2025 he is a Mercator Fellow of the Deutsche Forschungsgemeinschaft. He has recently completed a three-year term as Chair of the International Society for Infrared Millimeter and Terahertz Waves.