A team of physicists at the University of Sussex has developed the first non-linear camera capable of capturing high-resolution images of the interior of solid objects using terahertz (THz) radiation. According to the researchers, images composed of THz radiation are called “hyperspectra” because of its pixels — each one contains the electromagnetic signature of the article at that point.
Lying among microwaves and infrared in the electromagnetic spectrum, THz radiation quickly discerns materials such as paper, clothes, and plastic in the same way X-rays do, but without being dangerous.
THz radiation is safer to use with biological samples and makes it possible to visualize the molecular composition of objects and differentiate between different materials.
“The core difficulty in THz cameras is not about collecting an image, but it is about preserving the articles spectral fingerprint that can be easily corrupted by your technique,” explained Professor Peccianti of the Emergent Photonics (EPic) Lab. He has been working with Luana Olivieri, Dr Juan S. Totero Gongora and a team of research students on the project. “This is where the importance of our success lies. The fingerprint of all the details of the image is processed in such a way that we can investigate the nature of the article in full detail.”
The “EPic Lab” team used a single-pixel camera to image sample objects with patterns of THz light. Their prototype can discover how the purpose alters different patterns of THz light. By connecting this information with the shape of each original design, the camera exposes the image of an object, as well as its chemical structure.
Until now, cameras capable of capturing a hyperspectral image preserving all the fine details revealed by THz radiation had not been considered possible.
Sources of THz radiation are very faint and hyperspectral imaging had, until now, limited fidelity. To surmount this, The Sussex team shone a standard laser onto a unique non-linear material competent of converting visible light to THz. The prototype camera generates THz electromagnetic waves very close to the representation, similar to how a microscope works.
As THz waves can travel right into an object without affecting it, the resulting images reveal the form and composition of objects in three dimensions.
“This is a major step forward because we have demonstrated that all the circumstances explored in our previous theoretical research are not only possible, but our camera works even better than we expected,” said Gongora. “While developing our device, we discovered several ways to optimize the imaging method, and now the technology is stable and works well. The next stage of our research will be in speeding up the image reconstruction method and taking us closer to applying THz cameras to real- world applications, like intelligent car sensors, airport security, quality control in manufacturing, and even scanners to detect health issues like skin cancer.”