Som Tyagi Group – Drexel University

The molecular level specificity provided by Raman spectroscopy (RS) has made it a widely used spectroscopic tool for the determination of molecular structure and compound identification. Dr. Tyagi’s group has been studying Surface Enhanced Raman Scattering (SERS) in fractal aggregates fabricated from nano-particle printing inks. Fractal aggregates of metallic colloidal particles can provide hyper- enhancement for various linear and nonlinear optical responses, including RS. Such enhancement results from the localization of optical plasmon excitations within small parts (“hot-spots” a few to tens of nm in size) of a fractal aggregate. Since fractals are scale-invariant they, unlike translationally-invariant media, do not support propagating waves and hence can ‘trap’ electromagnetic field in very small volumes. When sufficiently concentrated, the large electromagnetic fields in the hot spots can result in very large SERS enhancement.

PA Department of Community and Economic Development

“Technology Investment Office looks to NTI as a valued partner in harnessing the technology based economic development opportunities within PA’s nanotechnology community.”

—C. Alan Walker
Secretary, PA Department of Community
and Economic Development