Abstract: Cascaded diffraction grated pairs are employed to form submicron gratings and other patterns in various types of devices using photolithographic, UV exposure and other techniques. Cascaded grating pairs are formed in masks which are positioned between a source of radiation and the device or substrate in which a grating is to be formed. The interaction of the diffracted beams generated by each diffraction grating in a cascade grating pair results in the device grating having a period which is substantially smaller than that of either of the gratings in the cascaded grating pair. As a result, gratings with substantially smaller periods than were previously obtainable can now be achieved using conventional fabrication techniques. To eliminate sensitivity to background exposure in photolithographic fabrication applications, a mask is employed in which first and second cascaded grating pairs are separated from one another by an opaque region that acts as a spatial filter.