High field terahertz plasmonics

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ObjectiveThe aim of this research program is to demonstrate new techniques for sensing and nonlinear spectroscopy using terahertz pulses with very high peak electric fields. Our approach is to combine our recent work on plasmon-induced field enhancements with newly developed techniques for high-energy terahertz pulse generation. Plasmonic interactions near subwavelength metal structures give rise to tiny regions of enhanced electromagnetic energy density. When these structures are excited by high-energy ultrashort pulses, the resulting field strengths will be huge, well into the regime of nonlinear optics. The combination of these two ideas, optimized for terahertz radiation, will open up a new realm of terahertz nonlinear optics.Intellectual MeritThe intellectual merit of this research program lies in the development of sensitive new techniques for time-resolved spectroscopic studies based on nonlinear interactions induced by strong terahertz fields. In addition, the ability to detect very small quantities of an analyte using terahertz nonlinear optical effects, with high temporal and spatial resolution, will reveal new dynamical processes previously obscured by limitations of sample size and inhomogeneity. Finally, this work will enable the study of nonlinear surface plasmon propagation, and will contribute to our understanding of high-field plasmon dynamics from terahertz to optical frequencies.Broader ImpactsBy generating the highest terahertz fields yet reported and studying their interaction with materials, this work will establish the possibility of exploiting higher-order nonlinear interactions. It will also demonstrate new techniques for terahertz-based sensing, which are of great technological importance. More broadly, this research will change our view of the limits of science in the THz regime by establishing a new discipline of high-field terahertz light-matter interactions.