Abstract

Advances in alternative plasmonic materials, specifically CMOS-­-compatible materials including refractory transition metal nitrides and transparent conducting oxides (TCOs), have propelled a new generation of nanophotonic devices for applications in on-­-chip optics, data storage, and energy conversion. As a plasmonic component, gold (Au) or silver (Ag) have some of drawbacks such as difficulty in fabricating ultrathin films, incompatibility with well-­-established processes for silicon-­-based products and lack of tunability, preventing them to be realized as practical devices in the telecommunication range. One potential transition metal nitride is titanium nitride (TiN), with a permittivity cross-­-over near 500 nm. TiN can attain ultra-­-thin, ultra-­-smooth epitaxial films on substrates such as c-­-sapphire, MgO, and silicon. Partnering TiN with CMOS-­-compatible silicon nitride enables a fully solid-­-state waveguide which is able to achieve a propagation length greater than 1 cm for a ~8 μm mode size at 1.55 μm. In fact, designs using TiN have outperformed similarly structured gold waveguides due in large part to the reduced scattering loss of epitaxial quality films.

© 2015 Optical Society of America