Grant: Discovery Grants Program - Individual

PLASMONICS AND ULTRASENSITIVE DETECTION. About 35 years ago it was discovered that small metal laser excited nanoparticles behave like high power speakers, in the sense that they can amplify the signal and make it extremely loud. The amplified signal carries the optical fingerprints of molecules located on or near the nanostructure. Because of the location of the molecule on the surface or near the surface of nanoparticles, the new physical finding was termed ""surface-enhanced spectroscopy"". Spectroscopy is the study of the optical fingerprints of atoms and molecules allowing us to indentify and classify them. Progress has been made controlling the degree of intensification and the ultimate limit of detection, a single molecule, has been achieved using silver and gold nanostructures. Soon, it was realized that the enhancement was directly connected to excitation of the electrons in the nanoparticle by the impinging light. The manipulation of light by metallic nanostructures is now a very broad field of research called plasmonics. The interdisciplinary field of plasmonics is today at the forefront of research in materials science, new advances in instrumentation and it provides the theoretical foundation for ""surface enhanced spectroscopy"". In our research, we apply plasmonics to guide the fabrication of silver and gold nanostructures for applications in ultrasensitive detection. The amplified light reradiated by the nanostructure carries the molecular fingerprint from molecular emission (surface enhanced fluorescence) or molecular scattering (surface enhanced Raman scattering). You can also detect the enhanced absorption, and each one of these techniques creates a new branch in the field of Analytical Spectroscopy with ultrasensitive applications in materials science, medical science and environmental science.