Monolithic double-grating phase mask for high-spatial-coherence large-period grating printing

Abstract : A monolithic double-grating phase mask comprising three short-pitch grating sections of spatial frequencies k1 and k2 collocated at one side of a substrate produces a large-period interferogram without higher harmonics to print in a photoresist film a latent grating of small spatial frequency equal to twice k2−k1. When incorporated in a write-on-the-fly scheme, the elements permit the fabrication of unlimitedly long gratings.