Transmissive data storage media and an optical head using holographic or acousto-optical deflection

The optical data storage system for use with a data storage medium, the system comprising in combination:

• an optical head for steering an incident optical beam using an acousto-optical method across the data storage medium wherein said incident optical beam is selectively reflected by the data storage medium to indicate a data bit recorded on the storage medium;
• said optical head being positioned in proximity to the data storage medium, such that an incidence angle ".THETA." formed between said incident light beam and a plane parallel to the data storage medium is less than 90 degrees, and including:
• a light source for emitting said optical beam;
• a beam steering element for steering said optical beam;
• a photo-detector for detecting a relative intensity of a deflected optical beam for detecting said recorded data bit;
• said beam steering element including an acousto-optical crystal for controlling a sweeping of said light beam;
• the data storage medium including an innermost track and an outermost diameter track;
• said incidence angle ".THETA." allowing said incident light beam to selectively sweep the surface of the data storage medium, between said innermost track and said outermost track;
• and
• the data storage medium further including a pattern of lands and pits;
• wherein at least some of said pits include a ridge which is substantially normal to said optical beam.