Too bad Gollum didn’t have one. A very special camera developed by the European Space Agency’s StarTiger (Space Technology Advancements by Resourceful, Targeted and Innovative Groups of Experts and Researchers – how’s THAT for an acronym?) recently took a picture of the human hand as seen in terahertz radiation, which is a virtually unexplored (and unexploited) region of the electromagnetic spectrum between microwaves and infrared light. Terahertz imaging is rapidly becoming recognised as a totally new diagnostic technique. By observing these types of waves, it is possible to see through many optically opaque materials. the imager could have various uses in the medical and security sectors. Terahertz waves could provide an image that has X-ray-like properties without the use of potentially harmful radiation. A terahertz imager is a passive instrument since the source of the signals occurs naturally from the object being imaged; so unlike X-rays it is completely safe. The imager built by the StarTiger team takes pictures at two frequencies, 0.25 and 0.3 THz, to create a two-color picture with contrast between materials having different transmission and reflection properties.
Several recent technology developments made it possible to build the StarTiger terahertz imager in its relatively small size. Attempts to construct a camera operating in the submillimetre wave range have previously resulted in very bulky solutions. Such cameras have primarily been based on waveguide-based technology and usually assembled from discrete elements. The recent advances in lithographically and micro-machining offered the potential for the realisation of the same performance with much smaller physical dimensions. “The StarTiger imager fits within a briefcase, is easy transportable. The core of the
instruments is the size of a cigarette package,” said project participant Peter de Maagt. “Next generation instruments will go for another magnitude smaller size, by using electronic scanning.” So soon police may be able to cruise the streets and scan passers-by on the sidewalk without their knowledge, looking for weapons and contraband…