Optical properties of ultrathin Au films on lithium niobate substrate

We present the first measurements of optical spectra for metal film-charged oxide structure. Gold films of different thickness were deposited by magnetron sputtering method on the surface of lithium niobate crystals. Transmission spectra of lithium niobate-Au structure before and after the structure annealing were measured and compared. The essential differences in spectra were found. Peak positions in absorption spectra for different initial film thicknesses were determined and conclusion about shift of absorption peaks into long wavelength range with film thickness increase is made. The causes of different behavior of curves for equal film thicknesses but oppositely charged surfaces of deposition are discussed.