17-GHz lossless InP-membrane active metasurface

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Abstract
High-speed active metasurfaces enable spatiotemporal light control within an ultrathin device layer, offering previously unexplored possibilities for optical communication, sensing, and computing. However, a trade-off between electrical conductivity and optical loss has hindered the realization of a high-speed, low-loss device. Here, we experimentally demonstrate an active metasurface operating at 1.5-μm wavelength range that achieves a record-high 17.5-GHz modulation bandwidth while maintaining a high quality ( Q ) factor of 102 and an ultralow optical loss of 0.56 dB. This is enabled by the indium phosphide (InP) membrane platform, where n-InP offers high electron mobility and low free-carrier absorption simultaneously. A high- Q Friedrich-Wintgen quasi-bound-state-in-the-continuum mode within the InP-membrane high-contrast grating (InP HCG) traps light in the organic electro-optic material for efficient modulation. The InP HCG also functions as an ultralow-resistance interdigitated electrode, enabling 50-fold faster modulation than silicon-based counterparts. Our work paves the way toward active metasurfaces for high-speed spatiotemporal light control beyond the GHz regime.
Funding Information
  • Japan Society for the Promotion of Science (JP23H05444, JP23H00272, JP21J11982, JP21J10272)
  • National Institute of Information and Communications Technology (JPJ012368C03601, JPJ012368C08801)
  • Materials Education program for the future leaders in Research, Industry, and Technolo
  • Materials Education program for the future leaders in Research, Industry, and Technolo

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