An optical data storage and retrieval 
system uses a flying head. The flying head is supported on a moving media having information stored in a plurality of stored data locations thereon. Information is stored in each of the plurality of media locations as physical structures capable of modulating the polarization state of incident light into one of two output polarization states. The flying head includes an 
optical processing assembly which directs an incident 
light beam having a source polarization state onto the moving media, accessing successive data locations. A reflected 
light beam having the source polarization state of the incident 
light beam modulated by a respective polarization modifying 
data location into one of the output polarization states is received by the flying head. The 
optical processing assembly optically transforms the modulated output polarization state of the reflected light beam into two return light beams having differentially modulated intensity related to the output polarization state of the reflected light beam. The two intensity modulated return light beams are optically coupled to a distal differential 
detector which outputs 
digital data representing the stored 
data information for the subject 
data location. A preferred embodiment includes optical fibers for 
coupling the incident and return light beams between the 
detector and the flying head. The optical 
assembly of a preferred embodiment includes an optical plate having pre-shaped and dimensioned recesses for automatically locating and aligning multiple optical components comprising the assembly. The flying head may also include a 
servo-controlled micro machined mirror for directing the incident and reflected light beams to and from the media.