Scientists exchanged quantum information on daylight in a free-space quantum key distribution

Scientists have reported a successful free-space quantum key distribution (QKD) in daylight with the self-developed polarization encoding chip for the first time. QKD is one of the most promising secure communication technologies, which encodes information into a single-photon, the smallest measurable unit of light. By using the quantum mechanical properties of the single-photon, quantum cryptography guarantees secure information exchange between the distant parties.