In this paper, it is shown that non-reciprocity can be observed in time-varying media without employing spatiotemporal modulated permittivities. We show that by using only two one-dimensional Fabry–Perot slabs with time-periodic permittivities having quadrature-phase difference, it is possible to achieve considerable non-reciprocity in transmission at the incidence frequency. To analyze such a scenario, generalized transfer matrices are introduced to find the wave amplitudes of all harmonics in all space. The results are verified by in-house finite-difference time-domain simulations. Moreover, in order to have a simple model of such time-varying slab resonators, a time-perturbed coupled-mode theory is developed for multiple resonances, and it is shown that the results obtained by this method and the analytical method are in excellent agreement.

中文翻译：

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使用正交相位时变平板谐振器的不可逆性

本文表明，在不采用时空调制介电常数的情况下，可以在时变介质中观察到不可逆性。我们表明，仅使用具有时间周期介电常数且具有正交相位差的两个一维Fabry-Perot平板，就可以在入射频率处实现相当大的非互易性。为了分析这种情况，引入了广义传递矩阵来找到所有空间中所有谐波的波幅。通过内部有限差分时域仿真验证了结果。此外，为了使这种时变平板谐振器具有简单的模型，针对多重谐振建立了时间扰动耦合模式理论，结果表明，该方法与解析方法所获得的结果吻合良好。 。