SNOM characterization of unmetalized and gold metalized DVD corrugated structures

This paper presents a study of the near-field optical profile of corrugated surfaces obtained from commercial digital versatile disk (DVD) patterns using a scanning near-field microscope (SNOM). The profile of the SNOM light intensity collected is related to the topography of the samples. The SNOM patterns consist of a periodic modulated light intensity along the corrugated surface with the same periodicity of the topography structure. For the virgin sample, the light profile has intensity peaks corresponding to the ridges of the DVD structure. However, when the corrugated surface is metalized with a thin gold film of 30 nm thick, the SNOM light intensity peaks are centred in the valley of the DVD structure. A Finite-Difference Time-Domain (FDTD) model has been employed to simulate the SNOM experimental data.