Encoding molecular information in plasmonic nanostructures for anti-counterfeiting applications

Area of Science:

• Plasmonics
• Nanotechnology
• Spectroscopy

Background:

• Current anti-counterfeiting measures face challenges with sophisticated replication techniques.
• There is a need for advanced security features with unique, unforgeable identifiers.

Purpose of the Study:

• To develop next-generation covert plasmonic security labels.
• To demonstrate the use of polarization-dependent surface-enhanced Raman scattering (SERS) for information encoding and retrieval.

Main Methods:

• Fabrication of silver (Ag) nanowire structures using two-photon lithography and thermal evaporation.
• Deposition of molecular probes onto Ag nanowire structures.
• Utilizing polarization-dependent SERS imaging for selective read-out of encoded molecular information.

Main Results:

• SERS signals from embedded molecules showed significant dependence on incident light polarization.
• Covert molecular information was not discernible from physical features alone.
• Polarization-dependent SERS imaging enabled selective read-out of encoded information.
• Plasmonic security labels exhibited narrow spectral fingerprints, offering high specificity.

Conclusions:

• Polarization-dependent SERS imaging provides a secure method for reading covert information.
• The combination of SERS spectral fingerprints and versatile geometrical design makes these labels ideal for anti-counterfeiting.
• Ag nanowire-based plasmonic security labels represent an advanced solution against product counterfeiting.