Sub-wavelength imaging and spectroscopy using terahertz plasmons

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ECCS-0724996Mittleman, DanielWilliam Marsh Rice UniversityIntellectual Merits:Terahertz science and technology has become one of the most exciting research frontiers in recent years. This long-neglected portion of the electromagnetic spectrum has attracted a great deal of attention, because of the many possible applications, ranging from basic science to applied engineering. One important research area is terahertz sensing, which exploits the unique spectroscopic signatures of materials for detection and identification. The terahertz range is spectroscopically rich, with many different substances possessing strong and unique absorption fingerprints. The field has been hampered, however, by the relatively poor sensitivity of terahertz systems. One may compare with state-of-the-art mid-infrared absorption spectroscopy, for which parts per trillion detection levels are attainable, or to surface-enhanced Raman scattering, which can be used to detect a single molecule. In order to achieve comparable sensitivity in the terahertz range, new configurations for imaging and spectroscopy are needed. The aim of this proposal is to develop sensitive new techniques for near-field sensing and spectroscopy using terahertz radiation. The approach is to exploit techniques that have been demonstrated at optical frequencies, based on the use of plasmonic field enhancements near sharp metal tips. The intellectual merit of this research program will be the new techniques that are developed, as well as the new window they provide on very low frequency Raman-active modes in molecular crystals and bio-molecular complexes.Broader Impacts:This work will have a broad impact in the area of terahertz science and technology, and in numerous other areas of optical physics. It will enable new sensing techniques, which are of great technological importance. It will provide a new avenue for the study of very low frequency Raman modes, which may be of fundamental importance in the understanding of biomolecular dynamics. It will also provide a multidisciplinary program for training new students in femtosecond optics, terahertz physics, and molecular sensing.