Fano-Resonant Metasurface with 92% Reflectivity Based on Lithium Niobate on Insulator

Abstract

Lithium niobate is an excellent optoelectronic and nonlinear material, which plays an important role in integrated optics. However, lithium niobate is difficult to etch due to its very stable chemical nature, and the microstructure of lithium niobate’s metasurface is generally of subwavelength, which further increases its processing difficulty. Here, by using Ar+-based inductively coupled plasma etching and KOH wet etching, we improve the etching quality and fabricate a Fano-resonant metasurface based on lithium niobate on insulator, which has a very high reflectivity of 92% at near-infrared wavelength and the potential of becoming a high-reflectivity film. In addition, to evaluate the practical performance of the metasurface, we constructed a Fabry–Perot cavity by using it as a cavity mirror, whose reflection spectrum shows a finesse of 38. Our work paves the way for the development of functional metasurfaces and other advanced photonic devices based on lithium niobate on insulator.

Plasmonic Sensing and Switches Enriched by Tailorable Multiple Fano Resonances in Rotational Misalignment Metasurfaces

“…Plasmonic Fano resonance (FR) generated by the interaction between the broad superradiant and narrow subradiant modes [ 11 , 12 ] results in strong field enhancement with a sharp asymmetric spectral profile that is utile for FR-based devices [ 13 ]. As in the following, the plasmonic FR promises new avenues for ultrasensitive sensing [ 14 , 15 , 16 ], optical switches [ 17 ], and digital metasurfaces [ 18 ].…”