Estimation of atmospheric refractive index structure constant using an InGaAs/InP single-photon detector

Remote sensing of atmospheric refractive index structure constant (C-n(2)) using lidar incorporating a single-photon detector (SPD) is proposed. The influence of turbulence on the fiber coupling efficiency with different fiber modes is analyzed. C-n(2) can be derived from the ratio of the back -scattering signals counted on single-mode and multimode fiber-coupling channels of the SPD. In the experiment, by eliminating the shot noise effect on the fluctuation of the ratio, the lowest coupling ratio is used to retrieve C(n)(2 )and demonstrated by comparing to the results measured from a large aperture scintillometer (LAS). Good agreement between results from the LAS and the lidar is achieved. The correlation coefficients are 0.90, 0.89, and 0.89, under three different weather conditions.(c) 2023 Optica Publishing Group