An international team of researchers, including ones from Aalto University, Shanghai Jiao Tong University, Zhejiang University, Sichuan University, Oregon State University, Yonsei University and the University of Cambridge, have designed a miniaturized spectrometer made of a ‘sandwich’ of different ingredients, including graphene, molybdenum disulfide, and tungsten diselenide.
The spectrometer reportedly breaks all current resolution records, and does so in a much smaller package, thanks to computational programs and artificial intelligence. The new miniaturized devices could be used in a broad range of sectors, from checking the quality of food to analyzing starlight or detecting faint clues of life in outer space.
Traditional spectrometers usually rely on bulky components to filter and disperse light. Modern approaches simplify these components to shrink footprints, but still suffer from limited resolution and bandwidth. Additionally, traditional spectrometers are heavy and take up extraordinary amounts of space, which limits their applications in portable and mobile devices. To address these problems, and shrink the size of the system, researchers have coupled layered materials with artificial intelligence algorithms. The result is an all-in-one spectrometer thousands of times smaller than current commercial systems. At the same time, it offers performance comparable to benchtop systems. In other words, these new spectrometers will provide portable alternatives to uncover otherwise invisible information, without even going into the lab.
“We eliminate the need for detector arrays, dispersive components, and filters. It’s an all-in-one, miniaturized device that could revolutionise this field,” said Dr. Hoon Hahn Yoon, from Aalto University in Finland, first author of the paper. This spectrometer-on-chip technology is expected to offer high performance and new usability across science and industry.
Different combinations of material components (among these, as was mentioned, are graphene, MoS2 and others) enable light detection beyond the visible spectrum, as far as the near-infrared region. This means the spectrometer detects more than just color, enabling applications such as chemical analysis and night vision.
The new devices could be incorporated into instruments like drones, mobile phones, and lab-on-a-chip platforms, which can carry out several experiments in a single integrated circuit. The latter also opens up opportunities in healthcare. In this field, spectrometers and light-detectors are already key components of imaging and diagnostic systems – the new miniaturized devices could enable the simultaneous visualization and detection of ‘chemical fingerprints’, leading to possibilities in the biomedical area.
“Our miniaturized spectrometers offer high spatial and spectral resolution at the micrometer and nanometer scales, which is particularly exciting for responsive bio-implants and innovative imaging techniques,” said co-author Professor Tawfique Hasan, from the Cambridge Graphene Centre.
The novel technology has huge potential for scalability and integration, thanks to its compatibility with well-established industrial processes. It could open up the future for the next generation of smartphone cameras that evolve into hyperspectral cameras that conventional color cameras cannot do. Researchers hope their contribution is a stepping stone towards the development of more advanced computational spectrometers, with record-breaking accuracy and resolution. This example, they say, is just the first of many.
