Complete material characterization is now possible using a state-of-the-art radar camera in the terahertz range together with conventional optical sensors. This multispectral terahertz camera is being developed at Fraunhofer FHR. The institute has focused on this type of technology for almost 60 years. Scientists are faced with the challenge of constructing a compact and cost-effective camera which is also »fast« and »reliable«.
The terahertz range is a part of the electromagnetic spectrum between microwaves and infrared with a frequency of one billion oscillations per second. Terahertz beams can penetrate most materials and are therefore capable of monitoring the thickness of a layer in a non-destructive manner and visualizing material flaws in ceramics or plastics. In contrast to UV radiation or x-rays, terahertz radiation is non-hazardous for humans and animals.
A full spectroscopic analysis over a large terahertz range would place very high demands on the hardware that is used to carry out the computing operations necessary for the material analysis. Such a solution is therefore not economically feasible. For this reason, frequency ranges with a very low bandwidth in the lower terahertz range have to be used and this, in turn, places special requirements on the corresponding evaluation algorithms. Fraunhofer IAIS is tackling this issue.