Fig. 5.

The $\pm |{\overrightarrow{\rho }}_j-{\overrightarrow{\rho }}_{51}|$ versus $z_j\text{-}{z}_{51}$ plot for $1\le j\le 100$ collected frames in a mode 2 scanning experiment. The line fitted to the curve has tan θ for slope and incidence angle $\theta =70\pm 0.1\mathrm{deg}$.