Abstract: An adhesive security tape comprises a polymer film whose refractive index and/or interface structure can be changed locally by heating. Disposed below the polymer film is an absorber layer comprising an absorber dye set up at least partly to absorb a write beam directed onto the absorber layer, to emit at least some of the generated heat to the polymer film locally, and in doing so to undergo local change itself. Below the absorber layer there is an adhesive layer. The adhesion between the adhesive layer and the absorber layer is greater than the adhesion to the polymer film. There is preferably a partly transparent reflection layer between the polymer film and the absorber layer.