Analysing real-world turbulence at low cost

Abstract

Absorption, scattering and refractive index fluctuations are three primary phenomena contributing to optical turbulence. Temperature fluctuations, humidity and air velocity cause variations on both temporal and spatial, in the refractive index of the atmosphere, leading to beam wander, loss of coherence, beam directional fluctuations and irradiance fluctuations. Whereas, absorption and scattering affect the propagation of a laser beam as the constituent gases in the atmosphere interact with the beam resulting in an attenuation of the beam. Remarkably, this has led to the developing of systems, where coherent imaging can be tailored to demonstrate turbulence effects at low cost. We demonstrate the simulation of atmospheric turbulence in the laboratory using a digital micromirror device. We illustrate the advantages of this approach, as well as some of the limitations. We show experimental results demonstrating these limitations, and we discuss the impact they have on the simulation of various turbulence strengths.