Abstract: An optical system for reading a plurality of radially contiguous individual holograms previously recorded on a rotatable disk along at least one of the disk tracks, each hologram being representative of a predetermined data pattern, and each being recorded as a Fourier transform hologram with respect tot the direction (y direction) tangential to the tracks and as a Fresnel hologram with respect to the radial direction (x direction), and wherein the optical system illuminates the disk with a read-out beam which is at least partially reflected by the disk to an array of photosensitive detectors which generates electrical data signals. A latch circuit is included for recovering the value of each data signal when the read-out beam completely illuminates one of the holograms.