A method is described for producing a grating, in particular an absorption grating, having a grating constant of less than 100 μm, by using a solution of superparamagnetic colloidal nanocrystal clusters (CNCs), a solvent liquid and a photocurable resin, with the following steps:—alignment of the CNCs in the solution by an external magnetic field,—exposure of the solution, so that the resin is cured and grating structures of an intended grating constant are formed, and—removal of the magnetic field.