Chiro-plasmon responses of x-shaped titanium nitride (TiN) nanoarrays by numerical simulations

Abstract Titanium nitride (TiN) has recently been taken as a potential candidate for plasmonic material, which supports surface plasmon resonances and exhibits excellent thermal stability. In this article, we proposed a novel chiral metamaterial with TiN, which consists of X-shaped TiN nanorods periodically arranged on a glass substrate. Its extinction, circular dichroism (CD) spectra, and g-factors were calculated and regulated by the detailed geometry through numerical simulations using the finite element method to further boost the application of TiN in chiro-plasmonic system. We show that it presents chiral responses both in visible and near infrared (NIR) ranges. Under the optimized geometric parameters and NIR incidence, it predicts ∼4 and 2 fold E -field enhancement and g-factor, respectively, than that of experimental reports of TiN nanohelices. The obtained excellent chiro properties are elucidated well in terms of the obtained superchiral field and charge distributions, whose origin was analyzed by a linear superposition method. Moreover, the influence of dielectric environments is discussed as well. Overall, the findings underscore the potential of TiN as a chiro-plasmonic refractory metamaterial and shed light on the design of alternative chiro-plasmon metamaterials for NIR applications in the future.