Diffraction-induced early-time diffusion of pulses propagating through scattering random media

We discuss here propagation of short electromagnetic pulses through dilute particulate random media consisting of scatterers in situations where the wave attenuation is dominated by scattering, rather than absorption. Examples of such phenomena include propagation of laser pulses through atmospheric clouds or through sprays in combustion processes. In such scenarios the coherent wave attenuation is controlled by the mean free path ℓ_t = 1/(n₀ σ_t), where n₀ is the medium number density and σ_t is the total cross-section for scattering of the wave on a single medium particle. The incoherent intensity is attenuated at a lower rate, but, typically, develops a long temporal tail due to multiple scattering in the medium and the ensuing diffusion. In both cases the medium effects cause serious deterioration of image quality in pulse-based imaging and bandwidth in communication; we propose here an approach for alleviating these difficulties.