Practical Free-Space Quantum Key Distribution over 1 km

Abstract

A working free-space quantum key distribution system has been developed and tested over an outdoor optical path of $\ensuremath{\sim}1\mathrm{km}$ at Los Alamos National Laboratory under nighttime conditions. Results show that free-space quantum key distribution can provide secure real-time key distribution between parties who have a need to communicate secretly. Finally, we examine the feasibility of surface to satellite quantum key distribution.