Experimental Study on the Intensity Scintillation Effect of Partially Coherent Light Transmission in Atmospheric Turbulence

In this article, the scintillation effect of laser beams with different initial coherence in the atmosphere is studied, and the expression of scintillation factor of partially coherent beams in the Gaussian Schell beam model is given. We designed and produced a multi parameter high-precision controllable laser source to generate partially coherent laser beams, and used a reproducible atmospheric turbulence simulation device to simulate atmospheric turbulence. On this basis, experimental research was conducted on the intensity scintillation effect of laser beams with different coherence lengths transmitted in atmospheric turbulence. The results indicate that as turbulence weakens (i.e. the atmospheric coherence length increases), the intensity scintillation effect caused by it on laser beams of different coherence lengths shows a decreasing trend. In addition, as the coherence length of the beam decreases, it is less affected by atmospheric turbulence (i.e. its intensity scintillation factor decreases). For a laser beam with a coherence length of 3mm, its scintillation factor is about 0.038 when the atmospheric coherence length is 5cm, while the fully coherent light has reached more than 0.16, with a difference of more than 4 times. Compared with the fully coherent beam, the partially coherent beam is not only smaller than the fully coherent beam in terms of the scintillation factor, but also the intensity fluctuation of its scintillation is smaller than that of the fully coherent beam.