“Bridging the Gap to Midwave Infrared Event-Based Sensors: Design, Sensitivity, and Radiation-Hardness Characterization of a Single-Pixel III-V Event-Based Infrared Sensor for Space Applications

Event-based sensing presents a revolutionary paradigm shift for next-generation space surveillance systems, where power consumption is an ever-worsening constraint as temporal resolution demands increase. In addition to reduced power consumption, low latency, and wide dynamic range, the event-based sensor fundamentally only produces data when there is a change in illumination from which events are generated; no data is produced if the scene remains static. With their event-based datastream being inherently focused on the dynamic information of the scene, they are particularly well-suited to machine vision and autonomous sensing applications. While these sensors have many compelling advantages, there are presently no commercial event-based sensors made to cover the mid-wave infrared spectral range. Since many space-based sensing applications are primarily concerned with this waveband to see through the 3-5 μm atmospheric transmission window, there is great motivation to investigate how mid-wave infrared III-V detectors will function with the event-based sensor unit cell to assess their performance and potential utility for space-based sensing missions.This work aims to bridge the gap between existing visible event-based sensors and emerging longer-wave infrared event-based sensing technologies by producing an event-based sensing testbed for rapid prototyping of candidate infrared detectors. Here, the event-based sensors pixel unit cell is implemented on a printed circuit board and interfaced with a mid-wave infrared III-V photodetector to facilitate rapid prototyping of these novel infrared event-based sensors. Measurements of variable area detector device sizes packaged in process evaluation chips allowed for detailed analysis and allowed for assessment of the sensitivity and noise contribution on the event-based sensor’s sensitivity performance metrics, and insight into possible limitations on using III-V mid-wave photodetectors. Additionally, the prototype mid-wave infrared event-based sensor performance is characterized as a function of proton irradiation to evaluate how the event-based sensor’s sensitivity degrades with displacement damage to the detector array; a characterization that is made uniquely possible by separating the detector element from the unit cell. The characterizations demonstrate how dark current, and quantum efficiency affect event-based operation, and in what way it translates into paradigms of event based sensitivity. The findings contribute to the foundational understanding of mid-wave event-based sensor design and provide a critical step toward the realization of radiation-tolerant, high-performance infrared event-based sensors for future space surveillance and defense applications.