Surface-Enhanced Raman Spectroscopy

Well-defined Al nanoparticle arrays fabricated over large areas
using extreme-UV interference lithography exhibit sharp and tunable plasmon resonances in the UV and deep-UV wavelength ranges.
Calculated near-field distribution of the electromagnetic field in the vicinity of Al nanoparticles. Finite-difference time-domain method was used for calculations.
Deep UV surface-enhanced resonance Raman of adenine molecules on the Al
nanoparticle arrays at a laser excitation wavelength of 257 nm. With this technique, reproducible, label free and real-time detection limit is estimated to be in the order of Zeptomole (∼ 30 000 molecules).
Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for enhancing the inherently low Raman scattering cross-sections of molecules, enabling detection down to single molecules. The major mechanism of the SERS effect arises from electromagnetic field enhancement in the vicinity of metallic nanostructures when they are excited at their surface plasmon resonance.

Our aim is to increase the enhancement factors of the SERS technique by developing novel designs and fabrication methods as well as using different excitation wavelengths ranging from UV to NIR. The objective of the project is to design, fabricate and analyze optical properties of metallic nanostructures and to perform Raman spectroscopy experiments of biomolecules. In particular, our current focus is deep-UV surface-enhanced resonance Raman scattering on aluminum nanostructures. We have recently demonstrated that this technique is a highly useful analytical technique for ultrasensitive and label-free detection of biomolecules in real time.