Stern‐Gerlach (SG) effect, initially found for unveiling the existence of quantized electron spins, is now a general concept describing a state‐dependent separation. It is widely explored in optics to achieve a function of optical splitting, but the current schemes always require a polarization‐ or wavelength‐dependent process, thus showing limitations for broader applications. Here, spatial modes of an optical field are employed as another degree of freedom to demonstrate an SG effect. Two modes of a pair of coupled waveguides are found to be in analog to the electron spins. They are able to undergo a splitting upon a spatially‐dependent waveguide coupling, which plays the role of a non‐uniform magnetic field. In an experiment, such a splitting is realized in two coupled non‐parallel slab waveguides, and its strength is adjusted at ease by varying the parameters of this proposed structure. This SG‐related optical splitting may find applications in the field of optical sensing and signal processing.

中文翻译：

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通过斯特恩-格拉赫效应分裂光学空间模式

斯特恩-格拉赫（SG）效应最初是为了揭示量子化电子自旋的存在而发现的，现在已成为描述状态相关分离的一般概念。它在光学领域被广泛探索以实现分光功能，但当前的方案总是需要依赖于偏振或波长的过程，因此在更广泛的应用中表现出局限性。这里，采用光场的空间模式作为另一个自由度来演示SG效应。一对耦合波导的两种模式被发现与电子自旋类似。它们能够在空间相关的波导耦合上进行分裂，这起到了非均匀磁场的作用。在实验中，这种分裂在两个耦合的非平行平板波导中实现，并且通过改变该结构的参数可以轻松调整其强度。这种与SG相关的分光可能会在光学传感和信号处理领域得到应用。