High-resolution examination of recording marks in phase-change media usinga scanning near-field optical microscope

Recording marks in digital versatile disc-random access memory (DVD-RAM) we re examined using a scanning near-field optical microscope (SNOM) incorpora ting an improved probe tip design. The marks were recorded on an experiment al DVD-RAM medium with a track-pitch of 0.6 mu m. The tip size of the SNOM was made wider than the track width in order tb avoid optical ghosting aris ing from the track edge. The recording power was varied in order to investi gate the dependence of the mark shape on power and it was found that the ma rk shape correlated well with the reproduced signal. The SNOM is considered -to be a good candidate for a practical characterization tool for optical r ecording media.