Abstract
Abstract
Bound states in the continuum (BICs) are theoretically known to possess infinite lifetimes and Q factor. However, due to the difficulties in achieving it in reality, symmetry breaking is often introduced in the structure to transform symmetrically protected BICs into quasi-BICs (q-BICs) with extremely high Q factor. Therefore, q-BICs can be utilized to enhance the Q factor of optical sensors. In this paper, we propose the design of a double-layer composite one-dimensional grating with a high Q factor. The structure consists of a double-layers silicon (Si) grating on a silicon dioxide (SiO2) substrate. By introducing a displacement in the upper-layer grating to break the symmetry, q-BICs are induced. The induced q-BICs achieve a Q factor of 2248 for transverse magnetic (TM) wave, enabling enhanced optical sensing capabilities. The proposed q-BICs sensor, exhibiting anisotropy for both TM and transverse electric wave (TE), holds great potential for narrowband polarizers and sensing applications.
Funder
Taishan Scholars Program
Natural Science Foundation of Shandong Province
National Natural Science Foundation of China
Subject
Atomic and Molecular Physics, and Optics,Electronic, Optical and Magnetic Materials
Reference47 articles.
1. On some peculiar discrete eigenvalues;Neumann;Phys. Z.,1929
2. Experimental observation of optical bound states in the continuum;Plotnik;Phys. Rev. Lett.,2011
3. Dynamic bound states in the continuum;Fan;Optica,2019
4. Bound states in the continuum;Hsu;Nat. Rev. Mater.,2016
5. Surface bound states in the continuum;Molina;Phys. Rev. Lett.,2012