High-Q hybridized resonance in a plasmonic metasurface of asymmetric aligned magnetic dipoles

Coupling of multipole moments in subwavelength structures opens up a space for engineering metamaterial properties for both fundamental studies and practical applications. In this paper, we demonstrate a high quality (Q) factor hybridized resonance mode in the mid-infrared region, which originates from head-to-tail coupled magnetic dipoles in a plasmonic metasurface. By arranging four metal bars of two different lengths in a cross-configuration in a planar metal-insulator-metal structure, we experimentally realize a strong hybridized resonance mode at 82.6 THz with a Q-factor of 60.2. The high-Q hybridized metamaterial mode exhibits distinct properties of polarization-selective excitation, cross polarization conversion, and a high figure-of-merit of 4 in refractive index sensing. These results suggest that hybridized metamaterial resonance is a promising platform with great potential for use in sensing, lasing, and polarization control.