The researchers designed a nanoscale node made out of magnetic and semiconducting materials that could interact with other nodes, using laser light to emit and accept photons. The device, say the researchers, demonstrates a way to use quantum properties of light to transmit information - a key step on the path to the next generation of computing and communications systems, which promise faster, more efficient ways to communicate, compute, and detect objects and materials.
The nanoscale node consists of an array of 120-nanometer high pillars, which are themselves part of a platform containing atomically thin layers of semiconductor and magnetic materials. The array is engineered so that each pillar serves as a location marker for a quantum state that can interact with photons and the associated photons can potentially interact with other locations across the device - and with similar arrays at other locations.
This potential to connect quantum nodes across a remote network, say the researchers, capitalizes on the concept of entanglement, a phenomenon of quantum mechanics that, at its very basic level, describes how the properties of particles are connected at the subatomic level.
"This is the beginnings of having a kind of register, if you like, where different spatial locations can store information and interact with photons," says Nick Vamivakas, professor of quantum optics and quantum physics at Rochester.
Building on previous work that uses layers of atomically thin materials on top of each other to create or capture single photons, the new device uses a novel alignment of tungsten diselenide (WSe 2) draped over the pillars with an underlying, highly reactive layer of chromium triiodide (CrI 3). Where the atomically thin, 12-micron area layers touch, the CrI 3 imparts an electric charge to the WSe 2, creating a "hole" alongside each of the pillars.
In quantum physics, a hole is characterized by the absence of an electron. Each positively charged hole also has