Multi-bits coding by multi-directional valley pits permitting stamper mass-production and remote direction readout by polarization reflection

A new concept of high-density memories by arrays of multidirectional V-shape pits and remote polarization readout is proposed. The polarization readout principles are examined by two model experiments. The first experiment with an array of 1 mum deep V-pits fabricated by FIB on a Si wafer, carried out under polarization microscope observation, confirmed the concept by the expected contrast variation among the pits images. Accuracy of the remote readout was examined by the second experiment configuring total reflection V-pits by a rectangular prism glued underneath a glass plate. Polarization detection sensitivity of the V-pit direction was found to be +/-0.14 degrees , which should easily accommodate 1.4 degrees =180 degrees /128 separation for 7 bits recording at every single V-pit.