Fig. 1. Simulation setup: a plane wave is incident on a cylindrical geometry filled with tiny spherical particles in motion. A “camera”, placed at a right angle, measures the resulting dynamic interferometric speckle pattern over time. Figure not to scale.

Fig. 2. Speckle contrast K dependence on scatterer velocity V for various camera integration times T. The error bars show the spread (standard deviation) caused by 10 different sets of random initial particle positions.

Fig. 3. Speckle contrast K dependence on scatterer “distance travelled”, d = VT. The data points are from Figure 2, and are shown to collapse onto a single master curve.

Fig. 4. Speckle contrast versus (τ_c/T)/w = d⁻¹. The data points are the same as in Figure 3. The values of w and β of models (2)–(4) are fit (exception: in the Lorentzian model β = 1 is used), using only the data points with d⁻¹ ≥ 3 × 10⁴.

Fig. 5. Speckle contrast versus (τ_c/T)/w = d⁻¹. The data points are the same as in Figure 3. The value of w of models (2)–(4) are fit, using only the data points with d⁻¹ ≥ 3 × 10⁴, and β = 1 is taken.