Manipulation of resonances governed by Fabry–Pérot bound states in the continuum
Xiaofeng Rao, Tao He, Chengfeng Li, Xinshang Niu, Chao Feng, Siyu Dong, Jingyuan Zhu, Zeyong Wei, Yuzhi Shi, Jifeng Qu, Zhanshan Wang, Xinbin Cheng
Abstract
Bound states in the continuum (BICs) have emerged as research hotspots in optics and photonics, offering a new paradigm for achieving extreme field localization and enhancing light–matter interactions. Here, we establish for the first time the intrinsic evolution laws of Fabry–Pérot bound states in the continuum (FP-BICs), revealing that the Q factor is inversely proportional to the square of phase/frequency detuning and to the nonradiative decay rate, enabling directional engineering of FP-BIC resonances. We propose an all-dielectric multilayer film metasurface to create an optical resonator and its perfectly mirrored counterpart, inducing FP-BICs and validating the conclusions. We experimentally demonstrated the evolution of the Q factor with frequency detuning, achieving a maximum Q factor of 610 in the visible. Our work offers novel insights into BICs, promising to inspire exotic phenomena and applications.