Kristen D. Alexander

I am currently a doctoral student in the Department of Physics and Astronomy at the University of North Carolina at Chapel Hill. My primary research interests lie in two main areas: the characterization of optically active nanostructures and the development of nanofabrication techniques that integrate these nanostructures into materials and devices. I am particularly interested in the large Raman signal enhancement factors in the tiny crevices between metal nanostructures, known as surface enhanced Raman scattering (SERS), and the use of this phenomenon to detect substances on the single molecule level. Potential applications of ultra-sensitive chemical sensors are of broad societal interest, including improved pathogen detection and medical diagnosis. Fabrication of reliable SERS substrates is currently limited by the fact that the precision required exceeds the limits of most available nanopatterning techniques. To address this problem, I am currently studying the fabrication of metal nanoparticle structures on deformable substrates. By varying the amount of mechanical strain applied to these substrates we are able to elicit control over feature position on the nanometer scale and study the properties of individual nanofeatures in depth. Overcoming the limitations of current fabrication techniques will provide a deeper understanding of this complex process and, ultimately, move towards a material impact of SERS on society. This technology has the potential to be used by professionals ranging from research scientists to doctors and first response teams scanning for harmful organic agents.