Scattering measurements on optical disks and their relation to media noise

We have conducted measurements of scattered light from bare polycarbonate a nd glass substrates and from complete optical disks using a He-Ne laser bea m in different polarization states and at different angles of incidence, Th e results axe compared with the measured media noise obtained from the same disks on a dynamic tester. Both the scattered light and the media noise or iginate from the jaggedness and other imperfections of the groove structure , the roughness of the substrate's surface, and the inhomogeneities of the bulk of the substrate. Although some sources of media noise manifest themse lves in the scattered light distribution, others cannot be easily detected by this type of measurement. (C) 2001 Optical Society of America.