Coupling characteristics and kurtosis parameter of partially coherent beams in turbulent atmosphere

ABSTRACT

Coupling properties and kurtosis parameter (K parameter) of arbitrary beams propagating through atmospheric turbulence are investigated. A correlation factor (C⁴-factor) is introduced to describe the influence of turbulence on coupling characteristics. The general analytical expression for C⁴-factor of arbitrary beams in atmospheric turbulence is derived. It is shown that C⁴-factor of arbitrary beams in the turbulent atmosphere depends on the initial second-order moments and fourth-order moments and turbulence quantities. Taking the partially coherent anomalous elliptical hollow Gaussian (PCAEHG) beam as an example, we can obtain that C⁴-factor decreases as structure constant of the refractive index fluctuations and inner scale increase, and waist width and transverse coherence length decrease when z > 5 km. Moreover, K parameter of PCAEHG beam in turbulent atmosphere converges to 2 when propagation distance is large enough. It indicates that the profile of PCAEHG beams in turbulent atmosphere finally evolves into fundamental Gaussian distribution.

KEYWORDS:

• PCAEHG beam
• atmospheric turbulence
• coupling properties
• C⁴-factor
• K parameter

Additional information

Funding

This research was supported by Sichuan Province Science and Technology Department foundation of China [grant number 2019YJ0470]; Young scholar for reserve talents of Xihua University [grant number 0220170303]; National Natural Science Foundation of China and Civil Aviation Administration of China [grant number U1433127]; Science Foundation of Civil Aviation Flight University of China [grant numbers JG2016-17, JG2017-17, JG2018-17].