a method of information conversion in which a recording medium is composed of a photoconductive member and a photo - modulation member both exhibiting a photoelectric effect and a dielectric mirror interposed therebetween , laminated to each other . an electro - magnetic radiation beam intensity - modulated with a serial information to be converted is radiated to the photoconductive member . the radiated beam is deflected straight along a surface of the photoconductive member to form a charge image composed of electric charges having an electric charge quantity corresponding to the information , as arranged in a straight line in a region on a border between the photoconductive member and dielectric mirror , corresponding to a region of the photoconductive member to which the beam is radiated . a two - dimensional bundle of electro - magnetic radiation beams of constant intensity and covering the region on the border is radiated to the recording medium at the photo - modulation member side thereof to take out a two - dimensional bundle of electro - magnetic radiation beams exhibiting intensity variation subjected to the charge image due to the photoelectric effect from the recording medium .