Roux, FS2011-10-072011-10-072011-01Roux, FS. 2011. Evolution of orbital angular momentum entangled bi-photon, propagating through a turbulent atmosphere. Complex Light and Optical Forces V, San Francisco, California, USA, 22-27 January 20119780819484871http://hdl.handle.net/10204/5206Complex Light and Optical Forces V, San Francisco, California, USA, 22-27 January 2011Orbital angular momentum (OAM) entangled bi-photons are a resource for the higher dimensional implementation of quantum cryptography, which allows secure communication over various channels. In the case where free-space is used as communication channel the initial OAM entangled bi-photon loses some or even all of its entanglement because of the scintillation that it experiences while propagating through the turbulence in the atmosphere. This decoherence of OAM entanglement has so far only been studied for the case of weak turbulence. Unfortunately, it is the more challenging strong turbulence scenario that is relevant for the practical implementation of free-space quantum communication through the atmosphere. Using an approach that differs from previous approaches, we derive a master equation for the evolution of an OAM entangled bi-photon during propagation through turbulence. However, in our approach the equation contains a derivative with respect to the propagation distance instead of time. The principle is to consider the propagation over an infinitesimal distance of OAM basis states through a random medium. This approach allows one to include, not only the effect of turbulence of arbitrary strength, but also the effect of the inner and outer scale of the turbulence, as represented by the Tartarskii and von Karman spectra. The resulting expression can predict the rates of decoherence for arbitrary initial OAM entangled states and can be used to calculate the concurrence, which measures the amount of entanglement, as a function of propagation distance for different initial entangled OAM states.enInfinitesimal propagation equationEntangle photonsAtmospheric turbulenceOrbital angular momentumDecoherenceOptical forcesComplex LightConference PresentationRoux, F. (2011). Evolution of orbital angular momentum entangled bi-photon, propagating through a turbulent atmosphere. http://hdl.handle.net/10204/5206Roux, FS. "Evolution of orbital angular momentum entangled bi-photon, propagating through a turbulent atmosphere." (2011): http://hdl.handle.net/10204/5206Roux F, Evolution of orbital angular momentum entangled bi-photon, propagating through a turbulent atmosphere; 2011. http://hdl.handle.net/10204/5206 .TY - Conference Presentation AU - Roux, FS AB - Orbital angular momentum (OAM) entangled bi-photons are a resource for the higher dimensional implementation of quantum cryptography, which allows secure communication over various channels. In the case where free-space is used as communication channel the initial OAM entangled bi-photon loses some or even all of its entanglement because of the scintillation that it experiences while propagating through the turbulence in the atmosphere. This decoherence of OAM entanglement has so far only been studied for the case of weak turbulence. Unfortunately, it is the more challenging strong turbulence scenario that is relevant for the practical implementation of free-space quantum communication through the atmosphere. Using an approach that differs from previous approaches, we derive a master equation for the evolution of an OAM entangled bi-photon during propagation through turbulence. However, in our approach the equation contains a derivative with respect to the propagation distance instead of time. The principle is to consider the propagation over an infinitesimal distance of OAM basis states through a random medium. This approach allows one to include, not only the effect of turbulence of arbitrary strength, but also the effect of the inner and outer scale of the turbulence, as represented by the Tartarskii and von Karman spectra. The resulting expression can predict the rates of decoherence for arbitrary initial OAM entangled states and can be used to calculate the concurrence, which measures the amount of entanglement, as a function of propagation distance for different initial entangled OAM states. DA - 2011-01 DB - ResearchSpace DP - CSIR KW - Infinitesimal propagation equation KW - Entangle photons KW - Atmospheric turbulence KW - Orbital angular momentum KW - Decoherence KW - Optical forces KW - Complex Light LK - https://researchspace.csir.co.za PY - 2011 SM - 9780819484871 T1 - Evolution of orbital angular momentum entangled bi-photon, propagating through a turbulent atmosphere TI - Evolution of orbital angular momentum entangled bi-photon, propagating through a turbulent atmosphere UR - http://hdl.handle.net/10204/5206 ER -