Polarization state detector systems and methods for read-out of multilevel oriented nano-structure optical media

A method, comprising:

• providing a system including:
• an optical beam source;
• a stage mounting thereon an optical disc medium for rotation about a central axis;
• at least one photodetector;
• a beam splitter positioned in an optical path between said optical beam source and said stage, for directing an incident beam of non-polarized light from said optical beam source onto said optical disc medium and directing a return beam from said optical disc medium onto said at least one photodetector;
• and
• an optical polarizer positioned in an optical path between said beam splitter and said at least one photodetector, for detection and analysis of changes in polarization of said return beam effected by variation of the orientation of walls and/or widths of pits or marks of said optical disc medium, wherein said optical polarizer comprises a non-polarizing beam splitter and first and second polarizing beam splitters, said first polarizing beam splitter having an optical axis oriented at substantially 45° to a horizontal position, said second polarizing beam splitter having an optical axis oriented at substantially 0° to a horizontal position;
• and
• determining orientation and/or width of pits or marks by correlating the intensity of first, second, third, and fourth exiting beams detected by the respective first, second, third, and fourth photodetectors with the light polarization orientation of said return beam.

A system, comprising:

• an optical beam source;
• a stage adapted 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 said optical beam source and said stage, for directing an incident beam of non-polarized light from said optical beam source onto said optical disc medium mounted on said stage and directing a return beam from said optical disc medium onto said at least one photodetector;
• and
• an optical polarizer positioned in an optical path between said beam splitter and said at least one photodetector, for detection and analysis of changes in polarization of said return beam effected by variation of the orientation of walls and/or widths of pits or marks of said optical disc medium, wherein:
• said optical polarizer comprises a non-polarizing beam splitter and first and second polarizing beam splitters, said first polarizing beam splitter having an optical axis oriented at substantially 45° to a horizontal position, said second polarizing beam splitter having an optical axis oriented at substantially 0° to a horizontal position.