Mie-coupled bound guided states in nanowire geometric superlattices

• Published in: Nature communications Vol. 9; no. 1; pp. 2781 - 9
• Main Authors: Kim, Seokhyoung, Kim, Kyoung-Ho, Hill, David J., Park, Hong-Gyu, Cahoon, James F.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 17.07.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 147/135; 639/624/1075/1079; 639/624/1075/401; 639/624/400; 639/925/357/1016; Coupled modes; Coupling; Geometry; Humanities and Social Sciences; Light; multidisciplinary; Nanotechnology; Nanowires; Optical components; Optical switching; Resonance; Resonance scattering; Science; Science (multidisciplinary); Superlattices; Wavelengths
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-05224-2

All-optical operation holds promise as the future of computing technology, and key components include miniaturized waveguides (WGs) and couplers that control narrow bandwidths. Nanowires (NWs) offer an ideal platform for nanoscale WGs, but their utility has been limited by the lack of a comprehensive coupling scheme with band selectivity. Here, we introduce a NW geometric superlattice (GSL) that allows narrow-band guiding in Si NWs through coupling of a Mie resonance with a bound-guided state (BGS). Periodic diameter modulation creates a Mie-BGS-coupled excitation that manifests as a scattering dark state with a pronounced scattering dip in the Mie resonance. The frequency of the coupled mode, tunable from the visible to near-infrared, is determined by the pitch of the GSL. Using a combined GSL-WG system, we demonstrate spectrally selective guiding and optical switching and sensing at telecommunication wavelengths, highlighting the potential to use NW GSLs for the design of on-chip optical components. The utility of nanowires for all-optical operation has been limited by a lack of coupling scheme with band selectivity. Here, the authors introduce a nanowire geometric superlattice that allows controlled, narrow-band guiding in silicon nanowires through direct coupling of a Mie resonance with a bound guided state.