Chiro-plasmonic refractory metamaterial with titanium nitride (TiN) core-shell nanohelices

Area of Science:

• Nanophotonics and Metamaterials
• Plasmonics
• Chiroptical Spectroscopy

Background:

• Chiral metamaterials enable optical polarization control but typically use noble metals (Au, Ag).
• Noble metals lack thermal stability and CMOS compatibility, limiting practical applications.
• Refractory materials offer a promising alternative for robust chiro-plasmonic systems.

Purpose of the Study:

• To demonstrate a novel chiro-plasmonic system using titanium nitride (TiN).
• To overcome the limitations of noble metals in visible-NIR metamaterials.
• To develop a scalable fabrication method for TiN-based chiral metamaterials.

Main Methods:

• Fabrication of TiN-coated silica nanohelices (core-shell structure).
• Assembly into 2D arrays over cm-scale areas.
• Scalable techniques: laser interference lithography, glancing angle deposition, DC magnetron sputtering.

Main Results:

• Broadband chiro-optical response from <500 nm to >1400 nm.
• Response attributed to individual and collective plasmon modes.
• Tunable spectral characteristics by controlling incident radiation direction.

Conclusions:

• Titanium nitride is a viable refractory material for chiro-plasmonic applications.
• The developed core-shell helix metamaterial exhibits excellent broadband chiro-optical properties.
• Scalable fabrication enables potential for large-area, stable chiro-plasmonic devices.