Impact of joint turbulence of jet engine and marine environment on the propagation quality of partially coherent generalized Laguerre–Gaussian correlated Schell model beams

This paper examines the transmission characteristics of the partially coherent generalized Laguerre–Gaussian Schell-model (GLGSM) beam in the joint turbulence of a jet engine and a marine environment. Firstly, we propose a theoretical model of the cross-spectral density for studying the evolution of the behaviors of spectral density and the degree of coherence. The analytical expression of the M²-factor is derived. These models are built by combining two processes of the extended Huygens–Fresnel principle and the second-order moments of the Wigner distribution function. Numerical results indicate that jet engine exhaust turbulence plays a dominant role in the effects of spectral density distribution specifically at short propagation, and, as the distance from the jet engine turbulence grows, the spectral density distribution resists intensity turbulence. Meanwhile, the degree of coherence weakens with significant propagation distance, lower source coherence width, and strong turbulence. Moreover, we find that the quality beam of GLGSM beam is better than Gaussian Schell-model beam and Laguerre–Gaussian Schell-model beam. The results also demonstrate that the normalized M²-factor decreases with the increase of mode order and wavelength, and decreases the source coherence width, which indicates that the GLGSM beam has a strong anti-turbulence ability with a higher index, longer wavelength, and lower source coherence width. The results of this study might be useful for directed infrared countermeasures, laser range finders, and laser designator systems on the aircrafts.