METHOD FOR PROTECTION FROM FORGERY AND CHECKING AUTHENTICITY OF VALUABLE ARTICLES Russian patent published in 2016 - IPC G07D7/00 B82Y10/00 

FIELD: physics.

SUBSTANCE: method includes forming, on a valuable article, a passive protective means of a given structure and enabling verification of presence and authenticity thereof. As the material of the protective means a metal (e.g., silver) or a semiconductor (e.g., silicon),is used, having a surface which is electrochemically treated until formation nanosized roughness. The detectable information features of the protective means used are generation of photoactivated "giant" second harmonic via laser illumination during electrochemical treatment of the surface, and verification of the presence and authenticity of the protective means is provided by analysing based on optical effects during external exposure to ionising electromagnetic radiation in the visible range and detecting information-bearing features in optical response of the protective means to said exposure.

EFFECT: high reliability of protection.

3 cl, 3 dwg