Abstract: A carrier is provided with a spiral structure in which sound and/or image information is stored in the form of frequency modulated or phase modulated signals. The carrier structure is composed of coplanar regions of variable length separated by coplanar areas of variable length. Where the regions and areas are all in the same plane the regions and areas have different coefficients of reflection or transmission. Where the regions and areas are not coplanar they are spaced by a distance sufficient to produce in response to impinging radiation a one-half wave length difference in the radiation exiting the regions and areas.Apparatus for imaging the radiation exiting the carrier structure is also disclosed.This is a continuation of application Ser. No. 396,399, filed Sept. 12, 1973, now abandoned, which is a continuation of Ser. No. 229,285, filed Feb. 25, 1972, now abandoned.