IN Brief:
- Dstl, Amethyst Research, and Lancaster University developed a new infrared detector architecture.
- The design increased detector efficiency more than tenfold while reducing unwanted thermal noise.
- Further work will develop an imaging demonstrator for potential use on drones, smaller platforms, and soldier-carried systems.
UK defence researchers have developed an infrared detector architecture that could reduce the cooling required by high-performance thermal cameras, potentially making capable imaging systems smaller, lighter, and less power-hungry. The work combines a thin absorber, a semiconductor reflector, and sub-wavelength structures to increase the amount of useful infrared energy captured while reducing unwanted thermal noise.
The Defence Science and Technology Laboratory, or Dstl, developed the technology with Amethyst Research and Lancaster University. The programme is aimed at thermal cameras required to operate in difficult battlefield conditions, including environments affected by smoke and dust where conventional visible-light imaging can become ineffective.
Thermal imaging works by detecting infrared radiation emitted by objects rather than relying on reflected visible light. That makes it valuable for surveillance, targeting, and situational awareness in darkness and degraded visibility, but extracting weak thermal signals at long range places demanding requirements on the detector itself.
Many high-performance infrared systems rely on cryogenic cooling to suppress the detector’s own thermal noise. Dstl gives an operating temperature of around 80K, approximately -193°C, for existing high-performance technology. Producing and maintaining that temperature requires cooling machinery that adds volume, mass, electrical demand, and mechanical complexity to the complete sensor.
Those penalties become increasingly restrictive as thermal cameras move onto smaller aircraft, uncrewed systems, vehicles, and soldier-carried equipment. A cooling system competes with batteries, communications equipment, other sensors, and mission payload for limited space and power, meaning detector temperature can influence the architecture of the complete platform rather than just the camera.
The new detector design tackles the problem through three linked features. A thin absorber layer is intended to reduce unwanted thermal noise, while a semiconductor layer acts as an optical reflector to keep infrared energy within the active region. Sub-wavelength structures then increase absorption of the incoming infrared signal.
Dstl reports that the combination increased detector efficiency by more than ten times while reducing thermal noise. The research points towards operation at temperatures closer to 150K, approximately -123°C. That remains extremely cold, but the difference between the two operating points can materially reduce the cooling burden imposed on the complete imaging system.
The engineering opportunity is therefore broader than a simple improvement in laboratory detector efficiency. If comparable imaging performance can be maintained with less cooling, a manufacturer can reduce the size, weight, and power demand of the camera. Alternatively, some of the system margin could be used for improved performance while retaining an existing cooling package.
Dstl identifies smaller platforms, drones, and soldier-carried cameras among the possible applications. Those environments also place additional requirements around vibration, shock, environmental sealing, start-up behaviour, battery life, and maintainability, so detector efficiency will have to survive integration into a complete electro-optical system before its military usefulness can be assessed properly.
The ability to work through smoke and dust is similarly more complicated than a single detector specification. Different infrared wavelengths interact differently with atmospheric conditions and obscurants, while range, target temperature, optics, image processing, and sensor noise all affect the final picture available to an operator. Increasing the useful signal reaching the detector nevertheless gives system designers more margin when the scene itself is difficult.
The programme also has an industrial dimension because advanced infrared detectors depend heavily on fabrication processes. A device structure can perform convincingly in laboratory testing but still struggle to become a practical product if semiconductor layers, microscopic structures, and packaging cannot be manufactured repeatedly at acceptable yield.
Working with a specialist company and a university gives Dstl a route to examine those manufacturing questions alongside the underlying detector physics. The next stage will mature the technology and produce an imaging demonstrator, moving the programme from individual detector performance towards something closer to a complete camera.
No procurement programme, production quantity, military platform, or fielding timetable has been announced. The work remains a technology-development effort, and the imaging demonstrator will be the next significant test of whether the reported efficiency improvement can be reproduced once read-out electronics, cooling, optics, packaging, and image processing are incorporated.
If it can, the practical result will be less dramatic than the underlying semiconductor research but more useful to equipment designers. High-performance thermal imaging currently brings a cooling system with it; reducing that dependency could make the same class of sensing practical on platforms where the machinery needed to reach 80K is currently a larger constraint than the camera itself.