AI powers all-in-one miniature spectrometer

An international research team led by researchers at Aalto University has developed high-sensitivity spectrometers with high wavelength accuracy, high spectral resolution and broad operation bandwidth, using only a single microchip-sized detector. The research for this ultra-miniaturised spectrometer was published in the journal Science.

Spectrometers are widely used throughout industry and research to detect and analyse light. Spectrometers measure the spectrum of light — its strength at different wavelengths, like the colours in a rainbow — and are useful for identifying and analysing specimens and materials. Integrated on-chip spectrometers can be of benefit to a variety of technologies, including quality inspection platforms, security sensors, biomedical analysers, healthcare systems, environmental monitoring tools and space telescopes. Postdoctoral researcher Hoon Hahn Yoon said that the single-detector spectrometer is an all-in-one device that measures light intensity at each wavelength beyond the visible spectrum. According to Yoon, the device is entirely controllable, with potential for scalability and integration.

“We designed this optoelectronic-lab-on-a-chip with artificial intelligence replacing conventional hardware, such as optical and mechanical components. Therefore, our computational spectrometer does not require separate bulky components or array designs to disperse and filter light. It can achieve high resolution comparable to benchtop systems but in a much smaller package. Integrating it directly into portable devices such as smartphones and drones could advance our daily lives. Imagine that the next generation of our smartphone cameras could be fitted with hyperspectral cameras that outperform colour cameras,” Yoon said.

Shrinking computational spectrometers is vital for their use in chips and implantable applications. Professor Zhipei Sun, the head of the research team, said that conventional spectrometers are bulky because they need optical and mechanical components, thereby limiting their on-chip applications. “There is an emerging demand in this field to improve the performance and usability of spectrometers. From this point of view, miniaturised spectrometers are very important for future applications to offer high performance and new functions in all fields of science and industry,” Sun said.

Professor Pertti Hakonen said that with further improvements in resolution and efficiency, the spectrometer could provide a new tool for quantum information processing. “Finland and Aalto have invested in photonics research in recent years. For example, there has been great support from the Academy of Finland’s Centre of Excellence on quantum technology, Flagship on Photonics Research and Innovation, InstituteQ and the Otanano Infrastructure. Our new spectrometer is a clear demonstration of the success of these collaborative efforts,” Hakonen said.

In addition to Postdoctoral Researcher Hoon Hahn Yoon and Professors Zhipei Sun and Pertti Hakonen, the key Aalto members linked to the work included Postdoctoral Researchers Henry A Fernandez and Faisal Ahmed, Doctoral Researchers Fedor Nigmatulin, Xiaoqi Cui, Md Gius Uddin and Professor Harri Lipsanen.

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