Quasi bound states in the continuum in 2D plasmonic crystals

Shihhui Gilbert Chang^1*, Yu-Yu Chen¹

¹Photonics, National Cheng Kung University, Tainan, Taiwan

* Presenter:Shihhui Gilbert Chang, email:gilbert@mail.ncku.edu.tw

High quality factor modes in plasmonic crystal structure are numerically demonstrated to resemble a quasi bound states in the continuum (BIC). A 2D square lattice of thin silver nanodisk arrays exhibits a quality factor greater than 3000 under P-polarization oblique angle excitation. The origin of such high Q mode is analyzed due to the anti-symmetric guided resonance mode in plasmonic crystal. The destructive interference of top and bottom surface radiation channels leads to the reduction of scattering loss similar to the BIC states in the photonic crystal. This special mode would potentially provide a highly sensitive biomedical plasmonic sensors or plasmonic laser applications.

Keywords: plasmonic crytal, bound states in the continuum