Optical properties and instrumental performance of thin noble metal (Cu, Au, Ag) films near the surface plasmon resonance

摘要

Surface plasmon resonance sensors are routinely employed optical instruments for biochemical research and suited for medical diagnostics. Optical properties and associated instrumental performance of nanometer thin sputter deposited Au, Ag and Cu films at the metal-water interface are reported and compared with theoretical predictions. Prominent optical SP-excitations persist in very thin metal films on BK7 glass substrates and metal film thickness of approximately 40-50 nm. Thin Au films are long-term chemically stable in neutral aqueous buffer solution. Cu and Ag films tend to deteriorate and oxidize over longer time period, especially when exposed to solutions with pH>7. Achievable sensor detectivities in the wavelength and angular interrogation modes are compared. The influence of surface oxidation on the irreversible adsorption of a common protein is also reported.