A new device consisting of a semiconductor ring produces pairs of entangled photons that could be used in a photonic quantum processor.
Quantum light sources produce entangled pairs of photons that can be used in quantum computing and cryptography. A new experiment has demonstrated a quantum light source made from the semiconductor gallium nitride. This material provides a versatile platform for device fabrication, having previously been used for on-chip lasers, detectors, and waveguides. Combined with these other optical components, the new quantum light source opens up the potential to construct a complex quantum circuit, such as a photonic quantum processor, on a single chip.
Quantum optics is a rapidly advancing field, with many experiments using photons to carry quantum information and perform quantum computations. However, for optical systems to compete with other quantum information technologies, quantum-optics devices will need to be shrunk from tabletop size to microchip size. An important step in this transformation is the development of quantum light generation on a semiconductor chip. Several research teams have managed this feat using materials such as gallium aluminum arsenide, indium phosphide, and silicon carbide. And yet a fully integrated photonic circuit will require a range of components in addition to quantum light sources.
