Current spectrometers that we have now work around the principle of taking the distance between different spectral components. And although this is a very helpful instrument, one disadvantage that it has is that its size can only accommodate spatial separation that is at least the size of a coin; any smaller than that would not be identified by current technology.
Recently, a team from Cambridge University has reported in Science that they have developed a technique that can work through this problem so that they can produce a system that is a thousand times smaller than what we currently can. To do this, the team worked with some colleagues all over the world from the UK, China, and Finland-and used a nanowire that had a gradient in composition along its length. This variation in material composition allowed the nanowire to be responsive to light across the visible spectrum. They adapted a manufacturing technique from makers of computer chips and then created a series of light-responsive sections on the nanowire.
First author from the Cambridge Graphene Center, Zongyin Yang, and co-first author, Tom Albrow-Owen, detailed how their technology works. "We engineered a nanowire that allows us to get rid of the dispersive elements, like a prism, producing a far simpler, ultra-miniaturized system than conventional spectrometers can allow. The individual responses we get from the nanowire sections can then be directly fed into a computer algorithm to reconstruct the incident light spectrum," said Yang.
"When you take a photograph, the information stored in pixels is generally limited to just three components - red, green, and blue. With our device, every pixel contains data points from across the visible spectrum, so we can acquire detailed information far beyond the colors which our eyes can perceive. This can tell us, for instance, about chemical processes occurring in the frame of the image," explained Albrow-Owen.
Lead researcher, Dr. Tawfique Hasan, also talked about how their device could be used in daily activities. "Our approach could allow unprecedented miniaturization of spectroscopic devices, to an extent that could see them incorporated directly into smartphones, bringing powerful analytical technologies from the lab to the palm of our hands," he explained.
While their research could be used in assessment of freshness of food, quality of drugs, or possibly identify counterfeit products, another application of the study that would cater great advancement in biology would be that it can create detailed images of cells and their chemical footprint without the need of a microscope.
In the future, the researchers hope to create an entirely new generation of ultracompact spectrometers having a wide array from the ultraviolet to the infrared range. This would be applicable in various fields such as research and development, industrial applications, laboratory scale applications, biological implants, and consumer smart devices, all these the researchers hope to see effective before 2025. The team has also processed the patent for their technology.
