as glass having an index of refraction lower than that of the member 52 upon the application of a voltage between the fingers 61 and 62 fringing electric fields established between the fingers produce a corresponding periodic strain in and at the interface of the member 52 and the film 53 this compressional strain at the interface of the materials 52 and 53 produces a spatially periodic variation of index of refraction of materials thereat thereby providing a diffraction grating which results in a redirecting of light along an output path therefrom the thickness of the film 53 in either of these latter embodiments need not be much more than the wavelength of the light being utilized as stated hereinbefore and diagrammatically illustrated in the fig6 embodiment of the invention light beam positioning means 70 such as the well known acousto optic light deflectors and a light beam collimating means 71 positioned along the input path 16 so as to effect a directing of light from the source 15 along a plurality of input paths paralleling the path 16 toward the prism surface 25 may be used to provide line scan input information or a combination of x and y input beam information line scan information may include for example the use of 100 500 or 1 000 individual input paths paralleling the path 16 and along which information bearing beams may be directed when so directed the number of such input paths being provided for will for example extend from a 0 reference point on the surface 25 in the direction of the length l of the distributor and thereupon establishing therein a corresponding number of primary.