Plasmonic materials for optical sensing and spectroscopy

The emerging field of plasmonics has great potential for advances in photonic materials, nanolithography and surface enhanced spectroscopy. The recent discovery of enhanced transmission nanoaperture arrays as a plasmonic building block for sub-wavelength optical components has produced substantial interest in a broad set of applied fields.; In this thesis, nanoaperture arrays are evaluated as SERS sensors. A SERS limit of detection study of the apertures arrays was performed and indicates that the enhanced transmission geometry may have useful applications as a molecular sensor. The SERS enhancement factors were calculated for a series of nanoaperture arrays with varied lattice spacing and compared to established SERS substrates. The transmission spectra of the aperture arrays were compared to theoretical predictions. The results indicate that the aperture arrays do not have similar transmission properties to previously published reports and transmission image analysis indicates that individual apertures within the arrays may have widely varying transmission spectra compared to the overall measured transmission spectrum from the array. The transmission image analysis may explain the lack of correlation between the transmission properties of the arrays and the observed SERS enhancement factors.