Robust Self-Healing of Bessel-Gaussian Beams under Geometric Obstructions for Free-Space Optical Communication

We experimentally generated Bessel–Gaussian (BG) beams and investigated their self-healing and speckle characteristics under various conditions. Diffracting and non-diffracting Bessel speckles were produced by scattering the beams and observing their near-field and Fourier-transformed far-field speckle patterns. The non-diffracting behavior was confirmed for both coherent and partially coherent BG beams. The topological charge of the beams, ranging from l = 1 to 10, was measured using a Mach–Zehnder interferometer, with forked interference fringes revealing the beam order. The self-healing property was analyzed by introducing geometric obstructions blocking 10% –70% of the beam, showing that the recovery distance increases from ~70cm to 170cm with the obstacle size and decreases with the axicon parameter. The recovered intensity decreases with increasing the obstruction, indicating a limit to the self-reconstruction capability. These findings demonstrate the robustness of BG beams for applications in optical manipulation, imaging, and free-space optical communication.