Level attraction and PT symmetry in indirectly coupled microresonators
Level attraction and PT symmetry in indirectly coupled microresonators
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DOI：
10.1103/physreva.102.043527
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发表时间：
2020-10
影响因子：
2.9
通讯作者：
Zhao-Hui Peng;C. Jia;Yuqing Zhang;Ji-Bing Yuan;L. Kuang
中科院分区：
文献类型：
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作者：
Zhao-Hui Peng;C. Jia;Yuqing Zhang;Ji-Bing Yuan;L. Kuang
利用它们的相位延迟和增益的可调性，我们展示了通过滴滤波导管间接耦合主动和被动微谐振器来实现能级吸引、宇称时间(PT)-和反数学{PT}对称光子结构的可能性。我们发现能级吸引来源于两种机制，即例外点和共振，在考虑微谐振腔的增益和损耗后，它不仅可以出现在耗散耦合中，还可以出现在相干耦合和混合耦合中，这证实了耦合光子系统中能级吸引的普遍性。另一方面，可以通过调节微谐振器的相位延迟和增益来实现从数学{PT}对称到反数学{PT}对称的转换，因此间接耦合微谐振器可以为展示数学{PT}对称和反数学{PT}对称的独特特征提供一个很好的平台。此外，我们还揭示了反射谱的线形和位相行为与数学{PT}对称性、反数学{PT}$对称性和能级吸引的内在联系。
Benefiting from the tunability of their phase delay and gain, we show the possibility of realizing level attraction, parity-time ($\mathcal{PT}$)-, and anti-$\mathcal{PT}$-symmetric photonic structures with indirectly coupled active and passive microresonators mediated by drop-filter waveguides. We find that level attraction originates from two mechanisms, i.e., exceptional point and resonance, and it may emerge not only for dissipative coupling but also coherent coupling and hybrid coupling after considering the gain and loss of microresonators, which confirms the universality of level attraction in the coupled photonic system. On the other hand, the transition from $\mathcal{PT}$ to anti-$\mathcal{PT}$ symmetry or vice versa may be realizable by tuning their phase delay and gain; thus the indirectly coupled microresonators may provide an excellent platform for exhibiting the unique features of $\mathcal{PT}$ and anti-$\mathcal{PT}$ symmetry. Furthermore, we also reveal the intrinsic relationship of the line shape and phase behavior of the reflection spectrum with $\mathcal{PT}$ symmetry, anti-$\mathcal{PT}$ symmetry, and level attraction.