Many current approaches for secure online communications involve encrypting algorithms in software to protect data. But a University of Oregon (UO) scientist is betting that fabricating artificial atoms onto a microchip can provide the needed security for future high-speed communications networks, according to research published in the journal Nano Letters.
The research was performed by UO physicist Ben Alemán, a member of the UO’s Center for Optical, Molecular, and Quantum Science. Alemán has made artificial atoms that work in ambient conditions, which he says could pave the way to develop secure quantum communication networks and all-optical quantum computing.
“The big breakthrough is that we’ve discovered a simple, scalable way to nanofabricate artificial atoms onto a microchip, and that the artificial atoms work in air and at room temperature,” Alemán, who is also a member of the UO’s Materials Science Institute, says.
To fabricate these atoms, Joshua Ziegler, a doctoral student researcher in Alemán’s lab, and colleagues drilled holes—500 nm wide and 4 nm deep—into a thin two-dimensional sheet of hexagonal boron nitride. The material is also known as white graphene because of its white color and atomic thickness.
The team drilled the holes using a process that resembles pressure-washing, but instead of a water jet, focuses a beam of ions to etch circles into the white graphene. They then heated the material in oxygen at high temperatures to remove residues.
Using optical confocal microscopy, Ziegler observed tiny spots of light coming from the drilled regions. After analyzing the light with photon counting techniques, he discovered that the individual bright spots were emitting light at the lowest possible level—a single photon at a time.
These patterned bright spots are artificial atoms and they possess many of the same properties of real atoms, like single photon emission.
When Alemán joined UO in 2013, he had planned to pursue the idea that artificial atoms could be created in white graphene. But when another university team identified artificial atoms in flakes of white graphene, Alemán instead sought to advance that research. Fabricating the artificial atoms is the first step toward harnessing them as sources of single particles of light in quantum photonic circuits, he says.
“Our work provides a source of single photons that could act as carriers of quantum information or as qubits. We’ve patterned these sources, creating as many as we want, where we want,” says Alemán. “We’d like to pattern these single photon emitters into circuits or networks on a microchip so they can talk to each other, or to other existing qubits, like solid-state spins or superconducting circuit qubits.”