International team develops scaled down spectrometer

The study, led by Finland’s Aalto University, resulted in a powerful, ultra-tiny spectrometer that fits on a microchip and is operated using artificial intelligence. The team’s findings are detailed in Science.

The research has led to a proof-of-concept spectrometer made with two-dimensional semiconductors that could be readily incorporated into quality inspection platforms, security sensors, biomedical analysers and space telescopes.

“We’ve demonstrated a way of building spectrometers that are far more miniature than what is typically used today,” said Ethan Minot, a professor of physics in the Oregon State University (OSU) College of Science. “Spectrometers measure the strength of light at different wavelengths and are super useful in lots of industries and all fields of science for identifying samples and characterising materials.”

Traditional spectrometers require bulky optical and mechanical components, whereas the new device could fit on the end of a human hair, Minot said in a statement. The new research suggests those components can be replaced with novel semiconductor materials and AI, allowing spectrometers to be scaled down in size from the current smallest ones, which are about the size of a grape.

“Our spectrometer does not require assembling separate optical and mechanical components or array designs to disperse and filter light,” said Hoon Hahn Yoon, who led the study with Aalto University colleague Zhipei Sun Yoon. “Moreover, it can achieve a high resolution comparable to benchtop systems but in a much smaller package.”

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The device is completely electrically controllable regarding the colours of light it absorbs, which gives it massive potential for scalability and widespread usability, the researchers said.  

“Integrating it directly into portable devices such as smartphones and drones could advance our daily lives,” Yoon said. “Imagine that the next generation of our smartphone cameras could be hyperspectral cameras.”

Those hyperspectral cameras could capture and analyse information not just from visible wavelengths but also allow for infrared imaging and analysis.

“It’s exciting that our spectrometer opens up possibilities for all sorts of new everyday gadgets, and instruments to do new science as well,” Minot said.

In medicine, spectrometers are already being tested for their ability to identify subtle changes in human tissue such as the difference between tumours and healthy tissue.

Minot added that for environmental monitoring, spectrometers can detect exactly what kind of pollution is in the air, water or ground, and how much of it is there.

“It would be nice to have low-cost, portable spectrometers doing this work for us,” he said. “And in the educational setting, the hands-on teaching of science concepts would be more effective with inexpensive, compact spectrometers.”