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 may be within reach in a few years, according to a team of Norwegian scientists who say they鈥檝e hit an important landmark.
As described in a paper published in the peer-reviewed , the team has created the 鈥渇irst high-quality microresonators鈥� able to access the longwave infrared spectrum of light for better detection and imaging.
鈥淲e鈥檝e built the lowest loss whispering gallery mode microresonator out there for the longwave infrared spectrum,鈥� Dingding Ren, a researcher at the Norwegian University of Science and Technology's (NTNU) Department of Electronic Systems, said 鈥淏ecause the longwave infrared spectrum provides definitive information about chemicals, it provides new possibility for sensing applications.鈥�
This development means researchers are able to utilize longer wavelengths of light, potentially opening up new possibilities for this technology, such as gadgets that could speedily identify minute differences in illnesses when presented with a sample.
Considering that the symptoms for viruses such as influenza, the common cold and COVID-19 can be similar or overlapping, being able to one day quickly diagnose yourself using a small household gadget could be groundbreaking. The release noted that researchers believe this technology could one day be utilized to detect diabetes as well.
Microresonators are a type of optical cavity that can store a significant amount of optical information inside a small container. Within the microresonator, light travels in circles, amplifying its properties.
鈥淲e can compare the microresonator to what happens with the sound in the whispering gallery in St. Paul's Cathedral in London,鈥� Ren explained.
In St. Paul鈥檚 Cathedral, if a person standing at one end of the room is whispering, a person standing at the other end can still hear them, even though it normally shouldn鈥檛 be possible to hear a whisper at that distance. What is happening is that the cathedral amplifies the sound waves through the precision of its shape and its walls in relation to each other. In a microresonator, a similar thing is happening to the light waves.
There are a plethora of uses for optical microcavities 鈥� for instance, they assist in long-distance transmission of data through optical fibres and are key in laser-reading or writing of CDs and DVDs.
Astrid Aksnes, a professor with NTNU鈥檚 Department of Electronic Systems, said in the release that being able to measure in the longwave IR range of the light spectrum, encompassing 8-14 micrometres, means more avenues for use in environmental monitoring and biomedicine.
鈥淢any molecules have fundamental vibrational bands in the mid-wave IR range (2-20 micrometres), the so-called 'molecular fingerprint region.' By measuring in this wave range, we achieve higher sensitivity,鈥� she said.
鈥淥ur microresonator is about 100 times better than what was available before for the longwave infrared spectrum,鈥� Ren said.
鈥淚t can retain the light 100 times longer than previous versions, which amplifies the optical field inside and makes nonlinear processes much easier, such as frequency comb generation.鈥�
Optical frequency combs were first developed for atomic clocks, keeping them exactly precise through careful transmission of information. Now frequency combs are found in your GPS and in fibre optic equipment used in computers and telephones.
Apart from improving the ease of frequency comb generation, this new microresonator may be useful for spectroscopic chemical identification 鈥� utilizing light to analyzing a sample to check for viruses and bacteria.
鈥淭he technology is still in its initial stage when it comes to measurements in this the longwave infrared spectrum of light. But our improvement gives us the possibility to identify several different chemicals in real time in the near future,鈥� Ren said.
Researchers achieved this more high-quality microresonator using native germanium, a chemical element commonly used in transistors, or semiconductor devices, in numerous electronics.
One of the benefits of using germanium is that it鈥檚 not particularly expensive, meaning that this technology could help to make spectroscopic machines more accessible. Currently, technology that uses spectroscopy to identify chemicals is only found in hospitals and other large institutions.
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 a type of salt.
We鈥檙e still a ways away from smart technology that uses microresonators to identify our illnesses in our home in moments. But with this new research, it seems progress is being made.
