In the near future, your cellphone or smartwatch will be able to tell you if you have COVID, the flu, or a cold, simply by analyzing the way you sniffle.

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In any case, this is the promise of a new study carried out within the Faculty of Electronic Systems at the Norwegian University of Science and Technology (NTNU).

NTNU researchers have developed a super-sensitive optical sensor called a microresonator that can analyze chemicals using the spectrum of infrared light.

This opens the door to devices that can use this technology to analyze gas or liquid samples for chemicals indicative of the presence of certain viruses and bacteria.

Principal researcher Dingding Ren said this microresonator is “100 times” better than previous sensors. Even though the technology is in the "early stage" of its development, devices using it will be able to perform detailed chemical analysis in the "near future".

Similar technology already exists on a larger scale - but the machines that can use infrared light in this way to identify complex chemicals are so large and expensive that they are mostly found in hospitals and institutions with big budgets.

Conversely, more common small machines can only identify a few chemicals in a sample and are therefore useless for finding the presence of a virus.

The key to the miniaturization of this technology therefore lies in this microresonator, whose full name is “whispering gallery mode microresonator”. A name that refers to an unusual phenomenon discovered at the Whispering Gallery of St. Paul's Cathedral in London.

Just as the shape of the gallery amplifies sound waves, the microresonator amplifies infrared light, allowing a small device to perform complex analysis.

This means that in the not-too-distant future, you'll be able to make sure you're not infected just with your phone before visiting your loved ones.