A High‐Speed Near‐Infrared Photodetector With an Ultra‐Wide Linear Dynamic Range for Machine Vision

ABSTRACT Short‐wavelength infrared spatial photodetectors for machine vision and optical networking hit bottlenecks of operation bandwidth and dynamic range with the growing density of the detector array. The key solution to challenge is the simultaneous optimization of high speed, high responsivity, and low noise in a small footprint. Here, we present a sub‐micron thick germanium‐on‐silicon photodetector which reaches an optimized built‐in field at zero bias, by which the dark current is also minimized. The compromised absorption due to low thickness is substantially enhanced by a resonant structure consisting of a plasmonic metasurface and a resonant cavity, resulting in an absorption of around 80% at 1310 nm. Without applying a bias, the engineered photodetector attains a responsivity of 0.65 A/W, a high‐speed operation bandwidth surpassing 40 GHz, and an extensive dynamic range of 180 dB. The ultra‐wide linear dynamic range is then employed in a machine vision task to demonstrate its effect in improving the recognition rate. The proposed photodetector exhibits an exceptional potential in cutting‐edge optical embodied intelligence applications.