Plasmonic color using titanium nitride for robust security devices

The subwavelength nature of the plasmonic resonances, observed in patterned thin metallic films, makes it an attractive choice for use in application such as security features, product branding and data storage and imaging. However, these have largely been limited by the practical issues of cost and robustness arising from the use of gold, silver or aluminum. Here we pattern TiN thin films, a well explored alternative plasmonic material, with sub wavelength apertures, arranged with hexagonal periodicity, which exhibit extraordinary transmission in the visible and near IR spectrum. These TiN structures are shown to withstand different levels of mechanical stresses, while gold doesn’t, making TiN an attractive platform for use as security features.