MRI: Design and Development of a Femtosecond Apertureless Near-field Microscope

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Technical AbstractUnder this project, a versatile apertureless near-field scanning optical microscope (a-NSOM) with femtosecond temporal resolution will be designed, constructed, and optimized at the South Dakota School of Mines and Technology. The completed instrument will bring to SDSM&T the capability to spatially-resolve spectroscopic properties in nano-materials and systems with subwavelength spatial resolution and ultrafast time resolution. The a-NSOM and associated instrumentation will enable collaborative research between faculty at SDSM&T and the University of South Dakota, including nano-optical studies of: the effect of nanostructure on luminescence upconversion and intermediate band absorption in solar cells, both important for so-called third generation solar energy conversion devices; the effects of chemical modification on semiconductor surfaces for photo-electrochemical hydrogen production; and the electromagnetic field enhancements in plasmonic nano-particle composite materials, important for enhanced nonlinear response in materials for all optical photonic switches with applications in future computation and communication devices. Such collaborations strengthen the South Dakota university consortium, focused on Photo-Active Nano Systems (PANS), by providing a unique tool for understanding the chemistry and physics of nano-structured surfaces. This proposed work will further build and support the newly formed, state supported, Nanoscience and Nanoengineering PhD program at SDSM&T, by enabling collaborative research opportunities for students and faculty in the program, as well as undergraduate science and engineering students in the state of South Dakota.Lay AbstractSpectroscopy is the systematic investigation of the optical properties of materials. It is now known that many unique optical properties of materials are a consequence of structure on the nanoscale (1-100nm), yet such length scales are inaccessible to the methods of classical optics due to the diffraction limit. The goal of this instrument development proposal is to design, assemble and optimize a versatile apertureless near-field microscope with femtosecond time resolution. The apertureless technique offers the potential to perform all-optical spectroscopic investigations with unprecedented temporal (~ 10fs) and spatial resolution (~ 10nm), thereby revealing the important connection between nanostructure and the optical properties of nanomaterials. The instrument will be used in collaborative research to develop new materials for improved solar cells, solar hydrogen production, and all optical switches for use in ultrafast optical computers and communication devices. The development of the proposed instrument will employ several undergraduate students, exposing them to opportunities in nanoscience and nanotechnology, and will be showcased in a course on nanophotonics, taught by the PI at SDSM&T. SDSM&T maintains a permanent Native American outreach program, serving the nearly 70,000 Native Americans in South Dakota. The PI's involved strongly support these efforts, and would utilize the instrumentation in outreach programs aimed at recruiting under-represented groups into science and engineering.