Most people have experienced the magic that can arise when you meet someone who is 'on the same wavelength' as you. A feeling of deep connection arises, communication flows effortlessly, and all signals are picked up and understood.
In quantum optics, something similar happens. Instead of people, light particles, called photons, carry and process information. When two photons have the same properties, such as frequency, they are impossible to distinguish from each other and will "interfere" with each other, which is key to developing quantum photonic technologies.
Furthermore, if the photons directly enter the frequency we currently use as standard in telecommunications and satellite communications, they can pass directly through the fiber optic network of cable lines that is already established in our underground, undersea, and airborne communications infrastructure.
This means that stable quantum connections can be established, the photons can retain their quantum states, and information can be sent securely over long distances.
Closed territory
At first glance, this sounds like a solution that everyone should choose. But for the vast majority of researchers, the technology is uncharted territory.
Only a few people in the world are capable of constructing crystals with quantum dots that emit photons that go directly to the standard frequency for telecommunications and satellite communications. One of them is Elizaveta Semenova, senior researcher at DTU Electro.
"The biggest advantage is that we minimize information losses," she explains.
She points out that this is one of the biggest challenges that other researchers in quantum photonics are struggling with when sending information over long distances.
"Most others in this field operate at a frequency that does not match the low loss window for transmission via optical fibers. So, to use the existing infrastructure, they must first convert their photons to the correct frequency. This process causes losses—and a risk of errors in the final calculations."
