Boosting pixel efficiency through metasurfaces in deadspace regions

Photodetector sensor arrays with coplanar electronics are increasingly used in emerging applications including high-speed communications, imaging, and sensing. These configurations place readout and signal processing electronics between sensing pixels, creating non-absorbing regions known as dead zones. While these regions are essential for pixel function and help reduce optical crosstalk, they also reduce the overall photon absorption efficiency of the array. This research explores the integration of metasurfaces within dielectric thin films in the dead space regions surrounding silicon photodetectors. We demonstrate that metasurface-enhanced designs significantly improve optical efficiency across a broad spectral range (640 nm to 1100 nm), without increasing device size. For single photodetectors, metasurface integration could simplify packaging and improve coupling efficiency.