In this proposal we request funds to purchase a state-of-the-art optical system for performing Near-field Scanning Optical Microscopy (NSOM) with spectroscopic capabilities. The promise of NSOM lies in its ability to provide wavelength-dependent optical imaging in spatial regimes well below the diffraction limit; its imaging and spectroscopic capabilities offer structural and compositional information at a spatial resolution much higher than traditional optical microscopy. The NSOM therefore comprises a crucial bridge between optical diffraction-limited systems and higher-spatial-resolution non-spectroscopic techniques such as atomic force microscopy and electron microscopy. Characterization of materials in this spatial regime is of paramount importance as the shift from "micro" to "nano" continues. The system will be configured to ensure an immediate contribution to research programs based at the University of Oregon in fields ranging from nanophotonics to biological sciences. The NSOM capabilities will be exploited to extend ongoing research on coherent optical phenomena in highly confining metallodielectric nanostructures. The requested system is ideally suited for investigation of plasmon localization, nonlinear plasmonics active nanoplasmonic systems. As NSOM has also been shown to be of great usefulness in the characterization of organic and biological materials, it will be used by several research groups with interests in these fields. In one project, it will be used to investigate the spatial organization of ion channels at synaptic active zones in receptor cells. In a separate research group the NSOM will facilitate spectroscopic imaging of surface-adsorbed biomolecules at the submicron level. In another project, charge transport in photoconductive organic semiconductors will be investigated at the single molecule level. As part of the multi-user Surface Analytical Facility at the University of Oregon, the NSOM would be optimally positioned to impact a broad range of emerging research programs, both within the university and outside, as well as expand the current facility user base.
This proposal addresses the acquisition of a specialized high-resolution microscopy system, capable of providing information about the structural and compositional characteristics of minute structures. A large variety of systems may be studied with this instrument; some examples include very small metal particles , biological cells, light-emitting molecules and thin oil slicks on water surfaces. What unites all of these systems is their size scale -typically about one half of one thousandth the width of a human hair, and often even smaller than that. Conventional optical microscopes such as those in high school science labs cannot reveal spatial features of objects at such small size scales. This limitation is inherent to all commonly available optical systems which employ light and lenses for visualization and magnification of images. The smallest spatial feature which may be distinguished using these instruments is about one half the wavelength of visible light - approximately five to ten times larger than the systems we are interested in studying. However, if instead of a lens a minute aperture (even smaller than our smallest object!) is placed at very high proximity to the sample, imaging of much finer features is possible when the aperture is illuminated with visible light. Such a system will allow students and researchers at the University of Oregon and its affiliated Institutions to elucidate the characteristics of novel systems such as the smallest light emitting structures known to nature, fabricate ultra-compact electronic and optical devices, understand how chemical contaminants interact with their immediate environment, and study biological cell structure and functionality with unprecedented optical resolution.
