Photonic gauge potentials are crucial for manipulating charge-neutral photons like their counterpart electrons in the electromagnetic field, allowing the analogous Aharonov–Bohm effect in photonics and paving the way for critical applications such as photonic isolation. Normally, a gauge potential exhibits phase inversion along two opposite propagation paths. Here we experimentally demonstrate phonon-induced anomalous gauge potentials with noninverted gauge phases in a spatial-frequency space, where near-phase-matched nonlinear Brillouin scatterings enable such unique direction-dependent gauge phases. Based on this scheme, we construct photonic isolators in the frequency domain permitting nonreciprocal propagation of light along the frequency axis, where coherent phase control in the photonic isolator allows switching completely the directionality through an Aharonov–Bohm interferometer. Moreover, similar coherent controlled unidirectional frequency conversions are also illustrated. These results may offer a unique platform for a compact, integrated solution to implement synthetic-dimension devices for on-chip optical signal processing.

中文翻译：

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频率空间中光子隔离的声子诱导异常规范电位

光子规范电位对于操纵电荷中性光子（如电磁场中的对应电子）至关重要，允许在光子学中产生类似的 Aharonov-Bohm 效应，并为光子隔离等关键应用铺平道路。通常，规范电位沿两条相反的传播路径呈现相位反转。在这里，我们通过实验证明了声子诱导的异常规范电位在空间频率空间中具有非倒置规范相位，其中近相位匹配的非线性布里渊散射使这种独特的依赖于方向的规范相位成为可能。基于此方案，我们在频域中构建光子隔离器，允许光沿频率轴非互易传播，其中光子隔离器中的相干相位控制允许通过 Aharonov-Bohm 干涉仪完全切换方向性。此外，还说明了类似的相干受控单向频率转换。这些结果可能为紧凑的集成解决方案提供一个独特的平台，以实现用于片上光信号处理的合成尺寸设备。