Quantum polarization fluctuations of a partially coherent Laguerre-Gaussian beam in a slant turbulent channel

The propagation of a partially coherent Laguerre-Gaussian beam in a slant turbulent channel is studied. The analytical formula for the quantum degree of polarization of a partially coherent Laguerre-Gaussian beam is derived based on the quantum Stokes operators and the extended Huygens-Fresnel principle. It is shown that the zenith angle slightly affects the polarization degree of partially coherent Laguerre-Gaussian beams, and the changes of polarization degree are affected by the detection photon-number. Furthermore, the numerical simulations show that a partially coherent Laguerre-Gaussian beam with higher photon-number level, lower beam orders, longer wavelength is less affected by the turbulence. These results indicate that one can choose the partially coherent Laguerre-Gaussian beam with lower beam orders, longer wavelength, higher detection photon-number to improve the performance of a polarization-encoded free-space quantum communication system.