Photon 'alphabet' gets easier to read

摘要

Secret agents take note: a new technique for extending the "alphabet" of individual photon shapes could improve encrypted communications. A photon's shape is based on the probability of detecting It at a particular place and time, depending on its amplitude and frequency. Quantum communication schemes can reliably send and receive photons that have been sculpted into just two variants, determined by the polarisation of the photon - either horizontal or vertical.