The invention relates to a method for concentrating light by coupling light into a thin film waveguide (2, 4) arranged on a substrate (1), in particular via at least one of its parallel surfaces, the method further comprising the step of exciting in the thin-film-waveguide (2, 4) at least one lateral guided mode (5) having at least one node (6), preferably exactly one node (6), by interaction, in particular scattering, diffraction or surface plasmon excitation of the incident light with a nanopatterned discontinuous excitation layer (3) of material, in particular metal, preferably silver, the nanopatterned discontinuous excitation layer (3) being arranged in the thin-film-waveguide (2,4) at the position of the at least one node (6) of the guided lateral mode (5). The invention furthermore relates to a light concentrator comprising a thin film waveguide (2, 4) deposited on a substrate (1), the thin film waveguide (2, 4) having at least two parallel surfaces, light being coupable into the thin film waveguide (2, 4) via at least one of these surfaces, wherein the thin film waveguide (2, 4) is established as a collecting thin film waveguide (2, 3, 4) for collecting light by arranging a nanopatterned discontinuous excitation layer (3) of material, in particular of metal and preferably of silver at a position corresponding to the node position (6) of a guided mode (5) to be excited in the collecting thin film waveguide (2, 3, 4). The invention also relates to a method of fabricating such a light concentrator.