@article{66674,
  abstract     = {{<jats:p>Efficient detection of near-infrared light at telecommunication wavelengths remains a central challenge for GaAs-based photonic and optoelectronic devices due to the absence of linear absorption below the bandgap. Here, we demonstrate a hybrid nonlinear optoelectronic device that enhances the detection efficiency of a (001)-oriented GaAs PIN photodiode under telecommunication-wavelength illumination, where absorption is intrinsically limited to two-photon absorption (2PA). Our approach relies on the integration of a transferred, nanopatterned 385 nm-thick (111)-oriented GaAs nanofilm acting as an on-chip nonlinear frequency-conversion layer. Elliptical GaAs nanoresonators are employed to enhance second-harmonic generation (SHG) resonantly, converting incident 1550 nm radiation into above-bandgap photons efficiently absorbed by the underlying diode. Spatially resolved current–voltage measurements reveal a pronounced enhancement of the detector response in regions covered by the nanoantennas. The device exhibits a low dark current, while the metasurface-covered regions show the largest current response under 1560 nm excitation compared to the bare GaAs(100) diode and the unstructured GaAs(111) film. These results establish a direct functional link between dielectric metasurface–based nonlinear frequency conversion and electrical photodetection, providing a viable route toward integrated sub-bandgap detection schemes.</jats:p>}},
  author       = {{Spedt, Vladimir and Meier, Falco and Geromel, René and Mahler, Pascal and Henksmeier, Tobias and Reuter, Dirk and Zentgraf, Thomas and Meier, Cedrik}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  number       = {{16}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Hybrid GaAs (111)/GaAs (100) PIN photodiodes for metasurface-assisted nonlinear upconversion detection}}},
  doi          = {{10.1364/oe.601288}},
  volume       = {{34}},
  year         = {{2026}},
}