Diffractive optical element with asymmetric microrelief for creating visual security features.

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Current optical security features face challenges with counterfeiting.
• There is a need for easily verifiable, robust anti-counterfeit technologies.
• Diffractive optical elements offer potential for advanced security applications.

Purpose of the Study:

• To develop and demonstrate a new visual security feature based on image transformation.
• To create a diffractive optical element exhibiting a "switch-180°" effect.
• To provide a secure and easily controllable anti-counterfeit solution.

Main Methods:

• Utilized Fresnel's scalar wave model to compute the phase function of the diffractive optical element.
• Developed efficient algorithms for designing flat optical elements capable of the "switch-180°" effect.
• Fabricated a sample diffractive optical element using electron-beam lithography.

Main Results:

• Successfully demonstrated the "switch-180°" visual effect with a fabricated optical element.
• The diffractive optical element features an asymmetric microrelief structure.
• The "switch-180°" effect was validated through photographic and video evidence from a real sample.

Conclusions:

• The developed "switch-180°" effect provides a secure and easily controllable method for authenticating optical security features.
• This technology offers effective anti-counterfeit protection for sensitive documents and products.
• The "switch-180°" security feature is practical and has been implemented for ID and excise stamp protection.