Most of the existing terahertz imaging solutions on the market are based on single point detection scheme. While being useful tools for proof of concept purposes, the time it takes to acquire an image of an object with these systems is prohibitively long for most of the real-world applications, where a real-time image acquisition is needed. A terahertz camera that can capture images of objects in real-time can open up its way into numerous industrial and security applications, where revealing a hidden object/feature behind an enclosure or inside a package is required.
The existing uncooled terahertz cameras on the market are based on microbolometer sensor technologies, the technology that has been traditionally used in night vision cameras. The uncooled microbolometer based camera technologies suffer from low sensitivity at the terahertz frequency range and hence need high power terahertz sources to operate. To increase the sensitivity of the detectors, superconductive based terahertz cameras have been developed and commercialized. This camera technology can detect tiny natural terahertz radiations from the objects and provide real-time terahertz images. The New York Police Department has started testing such terahertz camera technologies to detect firearms concealed beneath layers of clothing. The price one pays to achieve high sensitivity with these camera technologies is a six-figure price tag for a bulky system that can’t be adopted into many industrial applications where cost and size of the system is critical. Recent advancement in CMOS based terahertz detectors can potentially lead to high sensitivity, uncooled, compact, and low-cost terahertz camera technologies. There has been several proof of concept reports on CMOS based terahertz detectors, but no commercial system has been introduced to the market yet.
An uncooled, low-cost, and compact terahertz camera for non-destructive test and security applications remains the industry’s “holy grail”.