Entangled and non-line-of-sight (NLOS) free-space photon quantum communication [Invited]
Ronald E. Meyers, Keith S. Deacon · Journal of Optical Networking · 2005
Feature Issue on Optical Wireless Communications (OWC) We present new quantum communication (QC) schemes suitable for free-space (wireless) QC implementation. In particular, we present several entangled QC schemes and propose non-line-of-sight (NLOS) free-space photon QC. It is shown that in the presence of atmospheric scattering media, UV photons can be used for NLOS QC. Non-Poisson quantum fluctuations in an invariance regime can propagate farther than coherent laser speckle. In such situations the non-Poissonian statistics survive over long distances and should be taggable with a polarization signature. Quantum noise observables scale markedly differently with scattering parameters compared to classical noise observables. Variation of the polarization should allow Yuen-Kumar QC using non-Poissonian statistics of the beam as an authentication of the signal. The NLOS communication in the UV would be expected to be possible to at least a range of 1 km and falls under the category of deliberately short-range QC. Applications of importance for this method include military stealth and optical communication in the presence of obstacles such as a forest or urban environment.