Boosting pixel efficiency through metasurfaces in deadspace regions

Deadspace regions in sensor pixels are non-sensing areas typically used to house readout circuitry and reduce optical crosstalk. They are essential to pixel function but come at the cost of reduced overall efficiency. This work shows that incorporating metasurfaces into dielectric thin films within the deadspace region can enhance the optical efficiency of silicon photodiodes across a broad spectral range. The metasurface design is fully CMOS-compatible and eliminates the need for micro-lens integration. These concentrating pixels offer a promising path toward high-performance, low-cost pixel architecture well suited for applications such as free-space communication and time-of-flight sensing.