Published December 6, 2021 | Version v1
Journal article Open

Plasmonics on a Neural Implant: Engineering Light–Matter Interactions on the Nonplanar Surface of Tapered Optical Fibers

  • 1. Filippo
  • 2. Muhammad Fayyaz
  • 3. Antonio
  • 4. Marco
  • 5. Francesco
  • 6. Liset M
  • 7. Manuel
  • 8. Antonella
  • 9. Massimo
  • 10. Ferruccio


Optical methods are driving a revolution in neuroscience. Ignited by optogenetic techniques, a set of strategies has emerged to control and monitor neural activity in deep brain regions using implantable photonic probes. A yet unexplored technological leap is exploiting nanoscale light-matter interactions for enhanced bio-sensing, beam-manipulation and opto-thermal heat delivery in the brain. To bridge this gap, we got inspired by the brain cells’ scale to propose a nano-patterned tapered-fiber neural implant featuring highly-curved plasmonic structures (30 μm radius of curvature, sub-50 nm gaps). We describe the nanofabrication process of the probes and characterize their optical properties. We suggest a theoretical framework using the interaction between the guided modes and plasmonic structures to engineer the electric field enhancement at arbitrary depths along the implant, in the visible/near-infrared range. We show that our probes can control the spectral and angular patterns of optical transmission, enhancing the angular emission and collection range beyond the reach of existing optical neural interfaces. Finally, we evaluate the application as fluorescence and Raman probes, with wave-vector selectivity, for multimodal neural applications. We believe our work represents a first step towards a new class of versatile nano-optical neural implants for brain research in health and disease.


M.D.V., M.G., and Fe.P. jointly supervised and are co-last authors in this work. Fi.P., A.B., and Fe.P. acknowledge funding from the European Research Council under the European Union's Horizon 2020 Research and Innovation Program under Grant Agreement No. 677683. F.D.A., L.M.d.l.P., M.V., M.D.V., and Fe.P. acknowledge funding from the European Union's Horizon 2020 Research and Innovation Program under Grant Agreement No. 828972. Fi.P., M.D.V., and Fe.P. acknowledge that this project has received funding from the European Union's Horizon 2020 Research and Innovation Program under Grant Agreement No. 101016787. M.P., Fe.P., and M.D.V. were funded by the U.S. National Institutes of Health (Grant No. 1UF1NS108177-01). Open access funding provided by Istituto Italiano di Tecnologia within the CRUI-CARE agreement.


Pisano et al. - Plasmonics on a Neural Implant Engineering Light–.pdf

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Is identical to
10.1002/adom.202101649 (DOI)


MODEM – Multipoint Optical DEvices for Minimally invasive neural circuits interface 677683
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Controlling the spatial extent of light-based monitoring and manipulation of neural activity in vivo 1UF1NS108177-01
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