Real-Time High Resolution THz Imaging with a Fiber-Coupled Photo Conductive Antenna and an Uncooled Microbolometer Camera

We present a real-time THz imaging method using a commercial fiber-coupled photo conductive antenna as the THz source and an uncooled microbolometer camera for detection. This new combination of state-of-the-art components is very adaptable due to its compact and uncooled radiation source, whose fiber coupling allows for a flexible placement. Using a camera with high sensitivity renders real-time imaging possible. As a proof-of-concept, the beam shape of a THz Time Domain Spectrometer was measured. We demonstrate real time imaging at nine frames per second and show its potential for practical applications in transmission geometry covering both material science and security tasks. The results suggest that hidden items, complex structures and the moisture content of (biological) materials can be resolved. We discuss the limits of the current setup, possible improvements and potential (industrial) applications, and we outline the feasibility of imaging in reflection geometry or extending it to multi-spectral imaging using band pass filters.

A low-cost chopping system and uncooled microbolometer array for ground-based astronomy

Mid-Infrared imaging is vital for the study of a wide variety of astronomical phenomena, including evolved stars, exoplanets, and dust enshrouded processes such as star formation in galaxies. However, infrared detectors have traditionally been expensive and it is difficult to achieve the sensitivity needed to see beyond the overwhelming mid-infrared background. Here we describe the upgrade and commissioning of a simple prototype, low-cost 10 μ m imaging instrument. The system was built using commercially available components including an uncooled microbolometer focal plane array and chopping system. The system was deployed for a week on the 1.52 m Carlos Sanchez Telescope and used to observe several very bright mid-infrared sources with catalogue fluxes down to $\sim 600$ ∼ 600 Jy. We report a sensitivity improvement of $\sim 4$ ∼ 4 mag over our previous unchopped observations, in line with our earlier predictions.

Comparative Evaluation of a High Operating Temperature Midwave Infrared Detector for Automated Non-Destructive Inspection of Composite Damage

A new high operating temperature (HOT) midwave infrared (MWIR) imaging core is experimentally evaluated for use in automated inspection of composite impact damage by line scan thermography (LST). This evaluation is undertaken as part of a broader effort to develop an autonomous inspection capability for aerospace composite structures, deployable by ground and aerial robotic systems. The performance of the HOT MWIR core is assessed against a high-performance cooled photon-detector camera, an uncooled microbolometer core and an uncooled microbolometer camera, on two carbon epoxy laminate test specimens: one containing flat-bottom-hole synthetic defects and the other barely visible impact damage (BVID) introduced by controlled low-velocity impact. These test panels are scanned using a 3-axis robotic LST apparatus, at speeds of 25 and 100 mm/s. The HOT MWIR core is shown to match the detection performance of the cooled camera, and to significantly outperform both microbolometers. The high performance of this core combined with its relatively low mass, size and power consumption offers an encouraging basis for the development of a drone-deployable LST inspection capability.

Overview of the research work of Dr. Fukuhara in thermal infrared cameras across Hyabusa2, Akatsuki, Wildfire Monitoring and Lunar Flares

A technology that has only been recently introduced into astronomy and space exploration is infrared thermography (IRT) using uncooled microbolometer arrays (UMBA) to capture images. Assistant Professor Tetsuya Fukuhara, from the Department of Physics at Rikkyo University, Tokyo, Japan has been pioneering its use and over the last decade he has proved that UMBA IRT can uncover novel astronomical phenomena, help guide space travel and potentially allow satellites to stay precisely and accurately on orbit.