Effective Third-Order Nonlinearities in Metallic Refractory Titanium Nitride Thin Films

TL;DR

This paper investigates the nonlinear optical properties of titanium nitride thin films, demonstrating their high damage threshold and strong nonlinear response, making them promising for nanophotonic applications.

Contribution

It provides the first detailed study of third-order nonlinearities in titanium nitride, highlighting its advantages over traditional plasmonic materials like gold.

Findings

TiN exhibits a large nonlinear optical response comparable to noble metals.

TiN has a damage threshold up to ten times higher than gold.

TiN is compatible with CMOS technology and cost-effective.

Abstract

Nanophotonic devices offer an unprecedented ability to concentrate light into small volumes which can greatly increase nonlinear effects. However, traditional plasmonic materials suffer from low damage thresholds and are not compatible with standard semiconductor technology. Here we study the nonlinear optical properties in the novel refractory plasmonic material titanium nitride using the Z scan method at 1550 nm and 780 nm. We compare the extracted nonlinear parameters for TiN with previous works on noble metals and note a similarly large nonlinear optical response. However, TiN films have been shown to exhibit a damage threshold up to an order of magnitude higher than gold films of a similar thickness, while also being robust, cost-efficient, bio- and CMOS compatible. Together, these properties make TiN a promising material for metal-based nonlinear optics.