Fig. 4: The verification of crystallizing phenomenon of the 7 × 7 square lattices.
From: Optical vortex-antivortex crystallization in free space
a–d The experimental intensity patterns detected at different propagation distance: z = −0.65zR, −0.22zR, 0.22zR, and 0.65zR. e–h The phase measurements corresponding to a–d. This lattice possesses the same spacing and Gaussian width as the case in Fig. 3. The measured results well match the theoretical predictions including the intensity and phase distributions shown in i–l and m–p, respectively. The intensity and phase panels share the same scale bars, being 0.86 mm and 0.55 mm, respectively.
