Single-shot and reference-free measurement to characterize symmetry superposed optical vortices

Complex amplitude measurement is critical for precise light field characterization. In this work, we propose a single-shot and reference-free method to simultaneously measure the complex amplitude of symmetry-superposed optical vortices (SSOVs) using only a single CCD capture. Our approach combines two key innovations: one is a multi-ring extraction tactic for amplitude retrieval, and the other is a rotational measurement tactic for phase decoding. In proof-of-concept experiments, we demonstrate complex amplitude reconstruction and achieve mode purity measurements. The method's robustness, rapidity, and flexibility make it suitable for diverse applications, including harsh environments. Rigorous alignment protocols and error optimization further ensure measurement reliability with mode purity as high as 99.99% in only 0.24 s.