Patent ID: 6961296

Claim:
An apparatus for storing and retrieving data from a storage material having an inhomogeneous absorption, comprising: a laser that produces a laser beam having a frequency that sweeps through a frequency range; a signal generator that generates a reference signal; a data source that provides a data signal; an acousto-optic modulator that receives the reference signal, the data signal, and the laser beam and generates a reference beam and a data beam, the data beam modulated by the data signal, wherein the data beam and the reference beam are co-propagating; a scanner that scans the data beam and the reference beam across the storage material, so as to cause data to be stored in cells of the storage material; and a detector situated to recieve the reference beam transmitted by a cell and a reconstructed data beam produced by tranmission of the reference beam through the cell, the detector producing a heterodyne signal from the reference and reconstructed data beams, wherein the heterodyne signal has a modulation corresponding to data retrieved from the storage material.