The interplay between a photon and a quantum dot — a semiconducting blob of atoms — held inside a small cavity creates a device that can act as a qubit, the data-carrying building block of quantum computing.
Materials scientists would like to study information transfer between many such solid-state qubits. However, current construction techniques can create only a few unpredictable cavities and dots, thwarting attempts to build regular arrays.
Adrien Dousse and his colleagues at the Laboratory for Photonics and Nanostructures in Marcoussis, France, have now used laserguided etching to create, in one process, a dozen pillar-shaped cavities less than 3 micrometres wide, each containing an accurately tuned and positioned quantum dot. The technique could be scaled to create an assembly of identical qubits.