A group of physicists from the University of Sussex developed and created a prototype of the first of its kind non-linear camera, capable of using the radiation of the terahertz range to obtain high-quality images of what is inside solid opaque objects. Recall that terahertz radiation is between the microwave and infrared ranges of the electromagnetic spectrum, this radiation easily penetrates solid and opaque materials, but, unlike x-ray radiation, it does not harm the object. Therefore, terahertz radiation can be used to safely study and work with even the most sensitive and fragile biological samples.
Images obtained using terahertz waves are called hyperspectral due to the fact that each pixel of these images contains a kind of “electromagnetic signature” of the corresponding point inside the object. Further processing of such images allows one to “see” the molecular composition of objects and to distinguish individual chemical compounds.
Until recently, cameras capable of producing high-resolution hyperspectral images were beyond the capabilities of existing technologies. But scientists from the EPic Lab solved this problem by using a point (single-pixel) terahertz detector. At the same time, the object under study is illuminated by a stream of terahertz radiation, which encloses a certain predetermined image. The alternation of different images allows you to get a series of images, the combination of which gives the final image of the object and its chemical composition.
Existing sources of terahertz radiation are very weak and this is the reason for the limited resolution of hyperspectral cameras. This problem was solved in this case, by using a laser focused on a special material with nonlinear optical properties, which converted visible light into terahertz radiation, while simultaneously giving the flow of this radiation a specific image.
“It was a surprise for us that the camera we created worked better than we expected. This was due to the fact that we found several ways to optimize the processing and synthesis of images. Now the technology of such shooting works very well and stably,” says Dr. Totero Gongora (Dr. Totero Gongora), “The next thing we are going to speed up the process of synthesizing the final image, and if we can do this, the new non-linear camera can become the basis of many practical technologies, such as security systems tee, smart sensors, product quality control systems and, of course, medical diagnostic devices capable of detecting various diseases at an early stage”.