Active nonlocal metasurfaces
Abstract
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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 24, 2020
- Source ID
- 10.1515/nanoph-2020-0375
Entities
People
- Adam C Overvig
- Nanfang Yu
- Sajan Shrestha
- Stephanie C. Malek
Organizations
- Air Force Office of Scientific Research
- City University of New York
- Columbia University
- Defense Advanced Research Projects Agency
- National Science Foundation