A team of physicists at the University of Sussex has successfully developed the first nonlinear camera capable of capturing high-resolution images of the interior of solid objects using terahertz (THz) radiation.
The research team built a new type of THz camera capable of detecting THz electromagnetic waves with unprecedented accuracy.
Images produced using THz radiation are called ‘hyperspectral’ because the image consists of pixels, each one containing the electromagnetic signature of the object in that point.
Lying between microwaves and infrared in the electromagnetic spectrum, THz radiation easily penetrates materials like paper, clothes and plastic in the same way X-rays do, but without being harmful. It is safe to use with even the most delicate biological samples. THz imaging makes it possible to ‘see’ the molecular composition of objects and distinguish between different materials – such as sugar and cocaine
Until now, cameras capable of capturing a hyperspectral image preserving all the fine details revealed by THz radiation had not been considered possible.
The research team used a single-pixel camera to image sample objects with patterns of THz light. The prototype they built can detect how the object alters different patterns of THz light. By combining this information with the shape of each original pattern, the camera reveals the image of an object as well as its chemical composition.
Sources of THz radiation are very faint and hyperspectral imaging had, until now, limited fidelity. To overcome this, the team shone a standard laser onto a unique non-linear material capable of converting visible light to THz. The prototype camera creates THz electromagnetic waves very close to the sample, similar to how a microscope works. As THz waves can travel right through an object without affecting it, the resulting images reveal the shape and composition of objects in three dimensions.
The researchers say that the next phase of their research will be in speeding up the image reconstruction process and applying THz cameras to real-world applications; like airport security, intelligent car sensors, quality control in manufacturing and even scanners to detect health problems like skin cancer.
News Source: Eurekalert
