Progress towards home diagnostic technology: researchers

Scientists are one step closer to gadgets that might be able to answer an age-old question, and one that has become more important than ever since the start of the COVID-19 pandemic: do I have a cold, the flu or something else ? entirely?

Smart technology that could help diagnose you at home could be within reach in a few years, according to a team of Norwegian scientists who say they have reached an important milestone.

As described in a paper published in the peer-reviewed scientific journal Nature, the team created the « first high-quality microresonators » capable of accessing the long-wave infrared spectrum of light for better detection and imaging.

« We constructed the microresonator in low-loss whisper gallery mode for the long-wave infrared spectrum, » Dingding Ren, a researcher at the Department of Electronic Systems at the Norwegian University of Science and Technology (NTNU), said in a statement. Press. « Because the long-wave infrared spectrum provides definitive information about chemicals, it opens up new possibilities for sensing applications. »

This development means researchers are able to use longer wavelengths of light, potentially opening up new possibilities for this technology, such as gadgets that could quickly identify minute differences in diseases when presented with a sample.

Considering that the symptoms of viruses such as the flu, the common cold, and COVID-19 can be similar or overlapping, one day being able to quickly diagnose yourself using a small household gadget could be revolutionary. The release said the researchers believe the technology could one day also be used to detect diabetes.

Microresonators are a type of optical cavity that can store a significant amount of optical information inside a small container. In the microresonator, light travels in circles, amplifying its properties.

“We can compare the microresonator to what happens with sound in the whispering gallery of St. Paul’s Cathedral in London,” Ren explained.

In St. Paul’s Cathedral, if a person standing at one end of the room whispers, a person standing at the other end can still hear it, although it should not normally be possible to hear a whisper at this distance. What happens is that the cathedral amplifies the sound waves by the precision of its shape and its walls in relation to each other. In a microresonator, a similar thing happens with light waves.

There are a plethora of uses for optical microcavities – for example, they aid in long distance data transmission over optical fibers and are essential for reading or laser writing CDs and DVDs.

Astrid Aksnes, a professor in the Electronic Systems Department at NTNU, said in the release that the ability to measure in the long-wave IR range of the light spectrum, encompassing 8 to 14 micrometers, means more possibilities for use in monitoring environment and biomedicine.

« Many molecules have fundamental vibrational bands in the mid-wave IR range (2-20 micrometers), the so-called ‘molecular fingerprint region’. By measuring in this waveband we achieve higher sensitivity “, she said.

« Our microresonator is about 100 times better than what was previously available for the long-wave infrared spectrum, » Ren said.

« It can retain light 100 times longer than previous versions, which amplifies the optical field indoors and makes nonlinear processes much easier, such as generating frequency combs. »

Optical frequency combs were first developed for atomic clocks, keeping them perfectly accurate through careful transmission of information. Now, frequency combs are found in your GPS and fiber optic equipment used in computers and phones.

Besides improving the ease of generating a frequency comb, this new microresonator can be useful for spectroscopic chemical identification – using light to scan a sample for viruses and bacteria.

“The technology is still in its infancy when it comes to measurements in this spectrum of long-wave infrared light. But our improvement gives us the ability to identify several different chemicals in real time in the near future,” Ren said.

The researchers made this higher quality microresonator using native germanium, a chemical element commonly used in transistors or semiconductor devices, in many electronic devices.

One of the advantages of using germanium is that it is not particularly expensive, which means that this technology could help make spectroscopic machines more accessible. Currently, technology that uses spectroscopy to identify chemicals is found only in hospitals and other large institutions.

The researchers noted in the paper that to access even longer wavelengths, it might be necessary to use materials other than germanium, such as diamond or even some type of salt.

We are still a long way from smart technology that uses microresonators to identify our illnesses in our home in moments. But with this new research, it looks like progress is being made.


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