Figure 4

(a) Schematic of the ring used for the power-ratio calculation, where D1 and D2 represent the inner and outer ring radii, respectively. (b) The evolution of the ratio of the power in the ring \({p}_{\mathrm{r}}\) to the total combined field power \({p}_{\mathrm{t}}\) with the propagation distance in the cases of different random phases. \({PF}_{1}\)(phase fluctuation), \({PF}_{2}\), \({PF}_{3}\) represent three random phase fluctuation processes.