The last decade has been characterized by artificial electromagnetic (EM) materials, including photonic crystals (PCs) and photonic quasi-crystals (PQCs), making these very attractive given that there are new possibilities to control the EM field in innovative way. Quasiperiodic crystals (QCs) are a new class of materials that have fascinating optical properties lying somewhere between those of disordered and period structures. With the use of PCs and PQCs, it is possible to synthesize novel artificial structures characterized by selective EM responses, which, in turn, undergo significant frequency shifts, in presence of biological material. In the present work we studied artificial EM nanomaterials to develop innovative plasmonic nanobiosensors based on Surface Enhanced Raman Scattering (SERS) substrates and working in the visible and NIR frequency bands. A fabricated gold PQC in a Thue Morse arrangement is proposed for the engineering of reproducible SERS substrates. Structural characterization of this surface is performed by SEM and AFM. Optical properties of this plasmonic nanostructure are evaluated via UV/ Vis absorption spectroscopy and surface-enhanced Raman spectroscopy (SERS). Using a molecular monolayer of pMA (p-mercaptoaniline) as a Raman reporter, we show that a high value of SERS enhancement factor (measured up to 1.4 x 107) can be achieved in a properly optimized photonic structure, in good agreement with FDTD calculations. SERS enhancement factor is dependent on the plasmon absorption wavelength and laser wavelength used in these experiments. © 2015 SPIE.
|Titolo:||Surface-enhanced Raman spectroscopy on engineered plasmonic metamaterials for "label free" biosensing|
|Data di pubblicazione:||2015|
|Appare nelle tipologie:||4.1 Contributo in Atti di convegno|