Patent ID: 7995443

Claim:
A method to store information in a holographic data storage medium, comprising the steps of: supplying a holographic data storage medium comprising an encoded focusing hologram and one or more encoded data holograms; providing a first holographic data storage system comprising a light source, an optical detector array, a rotatable imaging lens, and a servo comprising a rotatable shaft extending outwardly therefrom, wherein said rotatable shaft comprises a spiral-threaded portion, and wherein said rotatable imaging lens comprises a periphery and a plurality of gear teeth disposed along said periphery, wherein one or more of said plurality of gear teeth are intermeshed with said spiral-threaded portion; disposing said holographic data storage medium in said holographic data storage system; disposing said rotatable imaging lens at an (i)th orientation, wherein (i) is initially set to 1; establishing a threshold focusing metric; illuminating said encoded focusing hologram with a reference beam to generate an (i)th reconstructed focusing image; projecting said (i)th reconstructed focusing image through said rotatable imaging lens, and onto said optical detector array; calculating an (i)th measured focusing metric; determining if said (i)th measured focusing metric is greater than or equal to said threshold focusing metric; operative if said (i)th measured focusing metric is greater than or equal to said threshold focusing metric, decoding said one or more encoded data holograms.