Physical Unclonable Functions Employing Circularly Polarized Light Emission from Nematic Liquid Crystal Ordering Directed by Helical Nanofilaments

Abstract

This study proposes the use of physical unclonable functions employing circularly polarized light emission (CPLE) from nematic liquid crystal (NLC) ordering directed by helical nanofilaments in a mixed system composed of a calamitic NLC mixture and a bent-core molecule. To achieve this, an intrinsically nonemissive NLC is blended with a high concentration of a luminescent rod-like dye, which is miscible up to 10 wt % in the calamitic NLC without a significant decrease in the degree of alignment. The luminescence dissymmetry factor of CPLEs in the mixed system strongly depends on the degree of alignment of the dye-doped NLCs. Furthermore, the mixed system prepared in this study exhibits two randomly generated chiral domains with CPLEs of opposite signs. These chiral domains are characterized not only by their CPLE performances but also by their ability to generate random patterns up to several millimeters, making them promising candidates for high-performance secure authentication applications.

Response of helielectric nematics under an in-plane electric field

“…1a). Thanks to the excellent electro-optic properties and fast electric-field tunability, Ch LCs have been the central target in establishing vast next-generation LC technologies such as liquid-matter-based sensors, 4 security 5 and anti-counterfeiting applications 6 photonic systems including optical modulators, 7 planar optics 8 and lasing devices. 9…”

Near-Infrared Circularly Polarized Luminescent Physical Unclonable Functions

“…Consequently, chiroptical materials capable of generating CPL have tremendous potential applications across various domains, including optical information storage, − optical communication, , optical displays, , optoelectronic devices, optical anti-counterfeiting, and information encryption. − These chiral optical materials are highly compatible with optical PUFs. For instance, Park and co-workers utilized chiral liquid crystals (LCs) to achieve chiral optical PUFs based on circularly polarized light . In addition, near-infrared (NIR) light is also a good type of covert light because of the naked-eye invisibility.…”