A grating light valve has with a plurality of spaced reflective ribbons are spatially arranged over a substrate with reflective surfaces. The grating light valve is configured to optimized the conditions for constructive and destructive interference with an incident light source having a wavelength .lamda.. The grating light valve preferably has a set of movable active ribbons alternating between the set of stationary bias ribbons. The active ribbons and the bias ribbons are spatially separated over the substrate surface such that reflective regions of the substrate surface correspond to the spaces between the ribbons. The ribbons and reflective regions of the substrate optically and geometrically optimized for to generate the conditions for constrictive and destructive interference with the incident light source. Accordingly, ribbons of the active ribbons are configured with reflective cross sections that are is approximately equal to the sum of the diffraction cross sections of the bias ribbons and the reflective regions of the substrate. In operation, active ribbons are moved by a multiple of .lamda./4 to switch between the conditions for constructive and destructive interference.