Focus: Photon Pairs Get More Commercial

A semiconductor chip that generates entangled photon pairs is friendlier to integration with other chip-based quantum components than any previous device.

Quantum cryptography, quantum computing, and other futuristic technologies require pairs of photons that are entangled, meaning they share a quantum state. Now researchers reporting in Physical Review Letters have taken a step toward making those pairs as part of an integrated circuit for photons that could ultimately include tiny lasers and optical “wires.” The team used a semiconductor chip in a structure that could allow other components to be added, whereas previous chip-based devices weren’t as practical for such integration. Producing entangled pairs as part of such a chip is potentially a significant step toward making them commercially available and perhaps even leading to future quantum-optical gadgets.