Spatiotemporal characteristics of dynamic speckle from a 3D target in atmospheric turbulence

Wang Liguo; Gong Lei; Li Yaqing; Yang Zhiqiang; Yang Lihong; Li Yao

doi:10.1016/j.heliyon.2023.e13121

Spatiotemporal characteristics of dynamic speckle from a 3D target in atmospheric turbulence

Heliyon. 2023 Jan 21;9(2):e13121. doi: 10.1016/j.heliyon.2023.e13121. eCollection 2023 Feb.

Authors

Wang Liguo¹, Gong Lei¹, Li Yaqing¹, Yang Zhiqiang¹, Yang Lihong¹, Li Yao¹

Affiliation

¹ School of Photoelectrical Engineering, Xi'an Technological University, Xi'an, 710021, China.

Abstract

Spatiotemporal correlation function is the basic characteristic of dynamic laser speckle and the basis of various applications. The correlation function of the speckle intensity from a 3D target in turbulent atmosphere is derived based on the model of random phase screen and Fresnel Kirchhoff Diffraction Formula, and a fast algorithm based on FFT is developed. The particularity of dynamic speckle in turbulence is numerically analyzed and discussed. The results show that the speckle intensity fluctuates at two independent scales both in space and time domain, which are affected by target size and atmospheric turbulence respectively. In particular, the time scale caused by turbulence is also affected by the target translating velocity and the wind direction. The theory and algorithm developed in this paper can play important roles in applications of laser speckle such as remote detection in atmospheric environment.

Keywords: 3D target; Atmospheric turbulence; Dynamic speckle; Spatiotemporal correlation function.