Active nonlocal metasurfaces

Nanophotonics

article

Stephanie C. Malek¹  Adam C. Overvig¹  Sajan Shrestha¹  Nanfang Yu¹ 

[1] Department of Applied Physics and Applied Mathematics, Columbia University;Advanced Science Research Center, City University of New York

关键词: metasurface;    nonlocal;    optical modulator;    quasi-bound states in the continuum;   

DOI  :  10.1515/nanoph-2020-0375

学科分类：社会科学、人文和艺术（综合）

来源: De Gruyter

【 摘 要 】

Actively tunable and reconfigurable wavefront shaping by optical metasurfaces poses a significant technical challenge often requiring unconventional materials engineering and nanofabrication. Most wavefront-shaping metasurfaces can be considered “local” in that their operation depends on the responses of individual meta-units. In contrast, “nonlocal” metasurfaces function based on the modes supported by many adjacent meta-units, resulting in sharp spectral features but typically no spatial control of the outgoing wavefront. Recently, nonlocal metasurfaces based on quasi-bound states in the continuum have been shown to produce designer wavefronts only across the narrow bandwidth of the supported Fano resonance. Here, we leverage the enhanced light-matter interactions associated with sharp Fano resonances to explore the active modulation of optical spectra and wavefronts by refractive-index tuning and mechanical stretching. We experimentally demonstrate proof-of-principle thermo-optically tuned nonlocal metasurfaces made of silicon and numerically demonstrate nonlocal metasurfaces that thermo-optically switch between distinct wavefront shapes. This meta-optics platform for thermally reconfigurable wavefront shaping requires neither unusual materials and fabrication nor active control of individual meta-units.

【 授权许可】

CC BY