Ultrahigh Q-Guided Resonance Sensor Empowered by Near Merging Bound States in the Continuum

Abstract

Bound states in the continuum (BICs) have attracted a lot of interest in the field of nanophotonics, and provide an important physical mechanism to realize high quality (Q) factor resonance. However, in practice, manufacturing error will greatly affect the Q factor. In this paper, we propose an asymmetric metasurface supporting near merging BIC under normal incidence. Such near merging BIC can achieve a higher Q factor (>107) than common structures (Q ~ 105) with the same degree of asymmetry in the structure. Moreover, the near merging BICs also show higher surface sensitivity than other resonant modes. Our work provides a promising approach for the realization of a high-performance biosensing platform.

Two Individual Super-Bound State Modes within Band Gap with Ultra-High Q Factor for Potential Sensing Applications in the Terahertz Wave Band

“…These unique features distinguish BICs from the traditional optical modes and significantly improve the performance of optical devices, especially for sensors, whose sensitivity is directly affected by the Q factor. In recent years, BICs were well explored in the literature for sensors in different structures, such as photonic crystals [ 7 , 18 , 19 ], metasurfaces [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ], and gratings [ 36 , 37 , 38 , 39 ]. These BIC sensors have different uses, for instance, refractive index sensing [ 7 , 25 , 28 , 30 , 36 , 39 , 40 ], biosensing [ 20 , 34 , 41 , 42 ], and gas detection [ 37 ], ranging from visible [ 37 ] to infrared [ 23 , 33 , 38 , 39 ] to THz [ 21 , 22 , 29 , 31 , 35 , 43 ] regions.…”

“…In recent years, BICs were well explored in the literature for sensors in different structures, such as photonic crystals [ 7 , 18 , 19 ], metasurfaces [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ], and gratings [ 36 , 37 , 38 , 39 ]. These BIC sensors have different uses, for instance, refractive index sensing [ 7 , 25 , 28 , 30 , 36 , 39 , 40 ], biosensing [ 20 , 34 , 41 , 42 ], and gas detection [ 37 ], ranging from visible [ 37 ] to infrared [ 23 , 33 , 38 , 39 ] to THz [ 21 , 22 , 29 , 31 , 35 , 43 ] regions.…”