Nonreciprocal optical devices based on magneto-optical ferrites in their low-loss regimes have been widely investigated as a promising platform for integrated photonics. Nonreciprocity in such devices originates from circular birefringence, leading to frequency splitting of forward and backward modes and, as a result, nonreciprocal transmission. In this paper, we propose an alternative approach to realize nonreciprocal devices based on magneto-optical circular dichroism and relying on the very presence of optical absorption. Our approach relies on the phenomenon of spin-Hall effect of light, which gives rise to chiral near field interactions of light carrying transverse angular momentum with matter, which, in lossy regimes, yields a disparate absorption for forward and backward optical modes. As an example of practical application, we design an optical isolator based on ring resonator integrating Ce:YIG ferrite, and we demonstrate isolation near 880 nm absorption line due to the ionic electric dipole transition. A Ce:YIG film asymmetrically placed on the inner side of the ring yields different critical coupling conditions due to the chiral nature of evanescent light for forward and backward waves, leading to nonreciprocal absorption and transmission. The proposed approach to nonreciprocity may significantly broaden the possible choice of magneto-optical materials for nonreciprocal devices, enabling operation even in lossy regimes.

中文翻译：

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基于手征光-物质相互作用的光隔离器集成了二向色磁光材料的环形谐振器

基于低损耗磁光铁氧体的非互易光学器件已被广泛研究，作为集成光子学的有前途的平台。此类器件中的非互易性源于圆形双折射，导致前向和后向模式的频率分裂，从而导致非互易传输。在本文中，我们提出了一种替代方法来实现基于磁光圆二色性并依靠光吸收的存在的非互易装置。我们的方法依赖于光的自旋霍尔效应现象，它引起携带横向角动量的光与物质的手性近场相互作用，在有损状态下，对前向和后向光模式产生不同的吸收。作为实际应用的例子，我们设计了一种基于集成 Ce:YIG 铁氧体的环形谐振器的光隔离器，并且由于离子电偶极子跃迁，我们证明了在 880 nm 吸收线附近的隔离。由于前向和后向波倏逝光的手征性质，不对称放置在环内侧的 Ce:YIG 膜会产生不同的临界耦合条件，导致非互易吸收和传输。所提出的非互易性方法可能会显着拓宽非互易设备磁光材料的可能选择，即使在有损状态下也能运行。由于前向和后向波倏逝光的手征性质，不对称放置在环内侧的 YIG 膜会产生不同的临界耦合条件，从而导致非互易吸收和传输。所提出的非互易性方法可能会显着拓宽非互易设备磁光材料的可能选择，即使在有损状态下也能运行。由于前向和后向波倏逝光的手征性质，不对称放置在环内侧的 YIG 膜会产生不同的临界耦合条件，从而导致非互易吸收和传输。所提出的非互易性方法可能会显着拓宽非互易设备磁光材料的可能选择，即使在有损状态下也能运行。