TWO-DIMENSIONAL DIFFRACTION GRATING WITH ALTERNATING MULTILAYER STACKS AND SPECTROSCOPIC DEVICE COMPRISING SAID GRATING

摘要

The invention relates to a two-dimensional diffraction network for the dispersion of polychromatic or quasi-monochromatic light fluxes, comprising a substrate (2) having a surface, (3), a first (5) and second (6) stack of biperiodic thin layers of a period d in the direction of the thickness thereof, consisting of at least two periods, each period being made up of layers of at least two different materials (7, 8), said stacks (5, 6) forming contiguous lines (11) of a width p/2 and which are parallel to each other and which are periodically repeated in a direction which is parallel to the surface of the substrate (2) with a period p, wherein the second stack (6) is alternated with the first stack (5) and is offset by a thickness d/2, such that the stacks (5 and 6) make up a thick network (9) which is borne by the substrate (2). According to the invention, said thick network (9) is formed by double-period repetition of a same elementary mesh surmounted by a thin surface network (10) whose width is at most equal to d/2.