Recent innovations in photonics and nanotechnology are now enabling terahertz (THz) research to be applied in many industrial fields such as homeland security, information and communications technology (ICT), biology and medical science, non-destructive tests or quality control of food and agricultural products. Still many challenges are to be addressed, the main one being to provide THz systems with sufficient signal to noise ratio when operated in real industrials conditions. In addition, cost is a key lock that hampers the spread of this technology but it is clear that cost-effective sources and detectors compatible with standard microelectronics will drive down the overall cost, and in particular will make THz imaging accessible for industrial use. In order to bring THz imaging to industry, Leti has been developing over the past decade complementary CMOS-compatible uncooled imaging 2D-array technologies: antenna-coupled bolometers and Field Effect Transistor detectors. In addition, CEATech built a test platform dedicated to the development of industrial prototypes of photonics technologies. In particular, in collaboration with i2S, this platform includes the TZCAM camera equipped with Leti’s 320×240 bolometric pixel array and gives access to a full industrial THz imaging chain that is essential for maturation of this emerging technology. This paper gives an overview of these developments and illustrates industrial applications with examples of uncooled THz imaging tests, e.g. opaque object 2D inspection or 3D tomography.
As for other imaging sensor markets, whatever is the technology, the commercial spread of terahertz (THz) cameras has to fulfil simultaneously the criteria of high sensitivity and low cost and SWAP (size, weight and power). Monolithic silicon-based 2D sensors integrated in uncooled THz real-time cameras are good candidates to meet these requirements. Over the past decade, LETI has been studying and developing such arrays with two complimentary technological approaches, i.e. antenna-coupled silicon bolometers and CMOS Field Effect Transistors (FET), both being compatible to standard silicon microelectronics processes. LETI has leveraged its know-how in thermal infrared bolometer sensors in developing a proprietary architecture for THz sensing. High technological maturity has been achieved as illustrated by the demonstration of fast scanning of large field of view and the recent birth of a commercial camera. In the FET-based THz field, recent works have been focused on innovative CMOS read-out-integrated circuit designs. The studied architectures take advantage of the large pixel pitch to enhance the flexibility and the sensitivity: an embedded in-pixel configurable signal processing chain dramatically reduces the noise. Video sequences at 100 frames per second using our 31x31 pixels 2D Focal Plane Arrays (FPA) have been achieved. The authors describe the present status of these developments and perspectives of performance evolutions are discussed. Several experimental imaging tests are also presented in order to illustrate the capabilities of these arrays to address industrial applications such as non-destructive testing (NDT), security or quality control of food.