Optical data storage using n path-entangled photons

摘要

An optical data retrieval system configured to retrieve data from a data storage medium 9, the system comprising: a source 1 of n path-entangled photons, where n is an integer of at least 2; a detector system 13 configured to determine if n photons have been received; and means (lens 7 and polarization beam splitter 5) to direct photons from said source to said data storage medium and to said detector system. The use of path entangled photons reduces the size of the spot that can be focused on the optical medium so that smaller data features can be resolved to increase data storage capacity. The Rayleigh criteria or diffraction limit which defines the size of features that can be resolved can be reduced by a factor n where n is the number of photons entangled in a multiphoton state.