Abstract

When two periodic patterns are superimposed, moiré pattern is generated. The moiré bands will move if we displace the revealing layer. When the revealing layer moves perpendicularly to layer lines, the moiré bands move along the same axis, but several times faster than the mov ement of the revealing layer. We study the effect of moving grating on the moiré fringes. We assume one of grating moves, respect to another one , with relativistic speed. The obtained moiré fringes are formulated according to the relativistic theory of light. The moiré fringes of such moving grating are studied and it is shown that, for relativistic velocity of grating, the displacement of moiré f ringes happens with a speed higher than the velocity of light in vacuum. Moreover, it is demonstrated that the moiré fringes displacement depends on the relative direction of gratings as well their step difference.