A polarization detection system structured for optical read-out of
disc-shaped optical data/information storage and retrieval media with
surfaces comprised of pits or marks configured as multilevel oriented
nano-structures (ONS) with varying pit or mark orientations and widths.
The polarization detection system comprises: an optical beam source; a
stage for mounting and rotating an optical disc medium about a central
axis; at least one photodetector; a beam splitter positioned in an
optical path between the source and stage, for directing an incident beam
from the source onto an optical disc mounted on the stage and a return
beam from the disc onto the photodetector; and an optical polarizer
positioned in an optical path between the beam splitter and the at least
one photodetector, for detection and analysis of changes in polarization
of the return beam effected by variation of the orientation of the walls
and/or widths of the pits or marks of the disc.