Sensors Unlimited, Inc. (SUI), a Raytheon company, has developed next-generation shortwave infrared (SWIR) and extended SWIR (eSWIR) imaging devices to enhance laser spot tracking, time-of-flight (ToF) ranging, and remote sensing performance. Leveraging in-house foundry advancements, SUI produced 2-D eSWIR focal plane arrays (FPAs) using a 640×512, 15 µm pitch format, extending wavelength sensitivity to 2.6 µm. These systems support multi-mode tracking (MMT), offering simultaneous imaging, asynchronous laser pulse detection (ALPD), and ToF operation at the pixel level, enabling robust performance under challenging environmental conditions.
Key innovations include the integration of InP/InGaAs avalanche photodiodes (APDs) with internal gain, reducing noise and improving detection range. Simulation and measurement results confirm low excess noise factors (<2 in linear mode) and high sensitivity, crucial for detecting weak or covert laser pulses. The latest MMT v4.0 sensors achieve frame rates up to 120 FPS for imaging and >20 kHz for pulse detection, with ToF depth accuracy within 1 cm and detection ranges exceeding 3 km.
Applications range from defense—such as battlefield laser designation, surveillance, and border security—to civilian uses in industrial automation, traffic monitoring, and precision remote sensing. The technology excels at tracking multiple laser spots simultaneously, operating effectively in varied lighting, weather, and countermeasure scenarios.
Future plans include expanding eSWIR performance, developing larger-format (2K×2K, 10 µm pitch) FPAs, and refining APD-based designs for even lower noise and higher sensitivity. These advancements position SUI’s MMT systems as leading solutions for long-range, high-resolution laser tracking in demanding operational environments.
