M. Yamaguchi et al., Imaging of digital versatile rewritable disc using the reflection-mode scattering-type scanning near-field optical microscope, JPN J A P 1, 40(3B), 2001, pp. 1578-1580
Recording marks written on the digital versatile rewritable disc (so called
DVD-RAM) by a blue violet laser diode were observed using a reflection-mod
e scattering-type scanning near-field optical microscope (RS-SNOM) for the
first time. The RS-SNOM is based on the atomic force microscope (AFM) and t
hus both the AFM and SNOM observations are simultaneously performed. In the
AFM image, the land/groove structure was clearly observed and no other con
trast appeared, while in the SNOM image, the 180-nm-long recording marks we
re clearly observed at the position of the groove. The contrast originated
from the difference in the refractive index, faithfully traced in the SNOM
image with a resolution of 50 nm. This result indicates that the RS-SNOM ca
n be used as an observation tool for the next-generation high-density optic
al media.