System aspects of dual-layer phase-change recording with high numerical aperture optics and blue laser

In this publication, key technologies for blue laser recording and dual layer phase-change disks with a total capacity of 50 Gbytes are explained and system margins are evaluated. Key challenges are the phase-change recording layer design, a robust read and write system with low intrinsic noise and the optical pickup design including, e.g., high numerical aperture (NA) objective lens, spherical aberration compensation devices and beam shaping optics. Blue-laser dual-layer technology will be emerging as the next-generation optical data storage standard beyond compact discs (CDs) and digital versatile discs (DVDs).