Robust self-healing of Bessel-Gaussian beams under geometric obstructions for free-space optical communication

Abstract

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 similar to 70 cm to 170 cm 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.