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Azimuthal backflow in multi-beam interference
DOI:10.1016/j.optcom.2025.132767.png)
Abstract
En 中文
We report an observation of azimuthal backflow both theoretically and experimentally by examination of the interference of three Gaussian beams carrying only negative orbital angular momenta. Different from that by utilizing the superposition of two beams, where only single backflow region can be observed, a configuration that fundamentally limits the complexity and symmetry of the resulting backflow pattern, here, it is shown that complex symmetric azimuthal backflow distributions are achieved by adjusting the topological charges and amplitudes of the three interfering Gaussian beams, The introduction of a third beam provides crucial additional degrees of freedom, enabling the generation of multiple backflow regions arranged in higher-order symmetric patterns (e.g., C3 symmetry), which were previously unattainable with two-beam interference. When one amplitude ratio is held constant, the number of backflow regions initially increases and then decreases as the other amplitude ratio progressively increases. Their dynamic relationships between backflow patterns with topological charges, amplitude ratios and propagation distance are uncovered. This demonstrates a significantly enhanced level of control over the backflow phenomenon.These findings advance our understanding of optical backflow and highlight some potential applications in optical trapping and wavefront shaping.
Keywords:
Azimuthal backflow
Multi-beam interference
Topological charges
Journal
IF:
2.5
Papers:
551
Citations:
2.7W

