This technology could become a reality within a few years, and electrical engineers are some of people who make it possible to create such gadgets, which contain a key component called the whispering gallery mode microresonator.
New technology is providing better optical sensors, which are important for electronics, including devices that analyse chemicals using light.
"We’ve built the lowest loss whispering gallery mode microresonator out there for the longwave infrared spectrum. Because the longwave infrared spectrum provides definitive information about chemicals, it provides new possibility for sensing applications," says Dingding Ren, a researcher at the Norwegian University of Science and Technology's (NTNU) Department of Electronic Systems.
Microresonators, which are a type of optical cavities, can store high optical field inside a very small volume. They can be made into a race track or disk geometry, but they usually are at a microscale dimension, similar to the thickness of a hair. Light travels inside the microresonator in circles, so the optical field gets amplified.
"We can compare the microresonator to what happens with the sound in the whispering gallery in St. Paul's Cathedral in London," says Ren.
This elliptical gallery has produced a famous phenomenon. You can whisper at one end of it and people at the other end of the room can hear you, even though they wouldn't normally be to able hear you at that distance. The sound waves are amplified by the shape of the room and the walls, which is how light waves behave in the microresonator.
"Our microresonator is about 100 times better than what was available before for the longwave infrared spectrum," says Ren. "It 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," he said.
Frequency combs are laser lights whose spectrum consists of a series of discrete, equally spaced frequency lines. These can be found various places, such as in your GPS, in atomic clocks and in fibre optic equipment used in telephones and computers. The technology also opens the door to analysing several chemicals at once, if a broadband frequency comb is available at the longwave infrared spectrum.
"The 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," says Ren.
COMPAMED-tradefair.com; Source: Norwegian University of Science and Technology (NTNU)
