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Infrared spectroscopy has found wide applications in the analysis of biological materials. A more recent development is the use of engineered nanostructures – plasmonic metasurfaces – as substrates for metasurface-enhanced infrared reflection spectroscopy (MEIRS). Here, we demonstrate that strong field enhancement from plasmonic metasurfaces enables the use of MEIRS as a highly informative analytic technique for real-time monitoring of cells. By exposing live cells cultured on a plasmonic metasurface to chemical compounds, we show that MEIRS can be used as a label-free phenotypic assay for detecting multiple cellular responses to external stimuli: changes in cell morphology, adhesion, and lipid composition of the cellular membrane, as well as intracellular signaling. Using a focal plane array detection system, we show that MEIRS also enables spectro-chemical imaging at the single-cell level. The described metasurface-based all-optical sensor opens the way to a scalable, high-throughput spectroscopic assay for live cells.
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Graphene metasurfaces for terahertz wavefront shaping and light emission [Invited]
Graphene is a promising materials platform for metasurface flat optics at terahertz wavelengths, with the important advantage of active tunability. Here we review recent work aimed at the development of tunable graphene metasurfaces for THz wavefront shaping (including beam-steering metamirrors and metalenses) and light emission. Various design strategies for the constituent meta-units are presented, ranging from metallic phase-shifting elements combined with a nearby graphene sheet for active tuning to graphene plasmonic resonators providing the required phase control or radiation mechanism. The key challenge in the development of these devices, related to the limited radiative coupling of graphene plasmonic excitations, is discussed in detail together with recently proposed solutions. The resulting metasurface technology can be expected to have a far-reaching impact on a wide range of device applications for THz imaging, sensing, and future wireless communications.
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- Award ID(s):
- 2111160
- PAR ID:
- 10416962
- Date Published:
- Journal Name:
- Optical Materials Express
- Volume:
- 12
- Issue:
- 12
- ISSN:
- 2159-3930
- Page Range / eLocation ID:
- 4528
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1364/OME.473110
