Fig. 5. Experimentally measured beam width and modal coupling results for our designed probe beams for probing a turbulence distribution with two different turbulence regions.

a Experimental setup for probing two emulated turbulence regions using two longitudinally structured beams (see “Methods” for more details). In the experiment, we set $Q=0.999997\mathrm{\times }k$ and $N=2$ to generate the two beams (Beam 1 and 2). They have narrow beam widths at 0<$\mathrm{z}$ < 0.3 m and 0.3 m < $\mathrm{z}$ < 0.6 m, respectively. Simulated and experimentally measured b, c intensity profiles and d beam widths of Beam 1 and 2 at different propagation distances. e Experimentally measured profiles and modal spectra of Beam 1 and 2 under one turbulence realization for four different turbulence cases, where regions 1 and 2 have different $r_0$.