Single-shot signed OAM decoding by symmetry-broken propagation of obstructed circular Airy vortex beams

Direct intensity measurements of rotationally symmetric pure CAVB modes cannot distinguish opposite OAM charges. We numerically demonstrate that an off-axis opaque stop breaks rotational symmetry and converts the phase handedness of a circular Airy vortex beam into a charge-dependent near-focus intensity pattern. After normalizing every image to the same intensity-weighted radius, a compact convolutional neural network distinguishes ten signed states, ℓ = ±1, …, ±5, with an accuracy of 99.94 ± 0.13% over five independent initializations, whereas a radius-only baseline reaches 23.4%. Centered-stop, unobstructed, and obstacle-plane controls fail to recover the OAM sign. A displacement-distance sweep further characterizes the numerically sampled operating range. These results demonstrate single-shot signed-OAM decoding through symmetry-broken propagation rather than generic vortex-beam robustness.