Abstract Method and apparatus for generating a plurality of separate and distinct signal beams of mutually coherent radiation. The signal beams, which are of substantially equal intensity, are produced as the result of interference generated by directing a beam of coherent radiation at a radiation-impeding medium having a plurality of regularly spaced and substantially identical zones of variable impedance (e.g., a plurality of very small cylindrical lenses or mirrors). The invention is illustrated as it might be used in apparatus for recording data in the form of a plurality of diffraction gratings of individually unique spatial frequencies effectively superimposed one upon another, the individual gratings being produced as the result of further interference patterns created by the intersection of a reference beam and each of the plurality of signal beams.
In a diffraction grating recording apparatus of the type wherein a source of coherent radiation is divided into a reference beam and a plurality of signal beams of corresponding wavelength and polarization, said beams being directed along different respective paths intersecting with one another in a predetermined recording area so that the interference of said signal beams and the reference beam will produce at said area a plurality of superposed line patterns of individually unique spatial frequencies, the improvement wherein the means for dividing said source radiation into said plurality of signal beams comprises: a lenticular film base including lens means having a plurality of very small cylindrical lenses arranged in linear adjacent parallel relation to intercept a portion of said source beam for separating said portion into a plurality of Secondary sources from which said radiation emanates to form an interference pattern comprising a plurality of separate and distinct beams of substantially equal intensity.
Claim 2
Dependent Claim
155 words
In a diffraction grating recording apparatus of the type wherein a source of coherent radiation is divided into a reference beam and a plurality of signal beams of corresponding wavelength and polarization, said beams being directed along different respective paths intersecting with one another in a predetermined recording area so that the interference of said signal beams and the reference beam will produce at said area a plurality of superposed line patterns of individually unique spatial frequencies, the improvement wherein the means for dividing said source radiation into said plurality of signal beams comprises: a lenticular film base including lens means having a plurality of very small cylindrical lenses arranged in linear adjacent parallel relation to intercept a portion of said source beam for separating said portion into a plurality of Secondary sources from which said radiation emanates to form an interference pattern comprising a plurality of separate and distinct beams of substantially equal intensity.
Claim 3
Dependent Claim
26 words
The apparatus according to claim 1 wherein said lens means includes two mutually perpendicular sets of said adjacent parallel cylindrical lenses aligned along a common axis.