Figure 3

Four two-dimensional wavefronts of the echo, based on simulation, with the same coherence length and different degrees of roughness. In (a) δ = 0 λ, (b) δ = 0.1 λ, (c) δ = 0.2 λ, and (d) δ = 0.4 λ.

Four two-dimensional wavefronts of the echo, based on simulation, with the same coherence length and different degrees of roughness. In (a) δ = 0 λ, (b) δ = 0.1 λ, (c) δ = 0.2 λ, and (d) δ = 0.4 λ.