A security element with a locally modified with regard to their light propagation characteristics of light-conducting structure and method for producing such a security element,

The invention relates to a method for producing a security element (1) and a security element (1), in particular for a value or security document comprising a Lichtleitstruktur, wherein the Lichtleitstruktur a transparent core (2) and a transparent cladding (7) and can take place wherein the refractive index of the core (2) is greater than the refractive index of the cladding, so that a total reflection to the light waveguide at the interface core (2) jacket (7) and as a light waveguide to an exit surface (75) of the core (2 is possible), wherein a volume transmission property of the core (2) is locally modified such that (in a light line in the Lichtleitstruktur at the exit surface 75) a result of the locally modified volume transmission property caused, is observable from the exit location-dependent intensity pattern of the exiting light.