基于Aharonov-Bohm笼的非厄米趋肤效应抑制现象

Suppression of non-Hermitian skin effect via Aharonov-Bohm cage

能带理论在光学领域的应用为控制光传输提供了有效手段,非厄米趋肤效应的发现扩展了传统能带理论的范畴,能够实现新型光局域和单向传输现象.然而在光学体系,如何有效地产生并调控非厄米趋肤效应仍然是重要的研究主题.本文研究了具有规范势的准一维菱形光晶格中的非厄米趋肤效应,通过计算本征能谱、环绕数和模式演化特性,发现规范势能够对趋肤效应强弱进行有效调节.当规范势大小为π时,趋肤效应被完全抑制,而由Aharonov-Bohm笼效应引起的平带局域占主导.利用间接耦合微环谐振腔阵列,可同时产生合成光子规范势和非对称耦合,为研究Aharonov-Bohm笼和趋肤效应的竞争机制提供了可能的实现方案.本研究结果为利用规范势调控趋肤效应提供理论基础,在发展片上非磁性单向传播器件也具有潜在的应用前景.

The application of energy band theory in optics provides an effective approach to modulating the flow of light.The recent discovery of non-Hermitian skin effect promotes the development of traditional energy band theory,which further enables an alternative way to realize light localization and unidirectional propagation.However,how to effectively generate and steer the non-Hermitian skin effect is still an important topic,especially in integrated optical systems.Here,we investigate the non-Hermitian skin effect in quasi-one-dimensional rhombic optical lattice with synthetic gauge potential.By calculating the eigenenergy spectra,spectral winding number,and wave dynamics,the gauge potential can be utilized to effectively tune the localization strength of skin modes.In particular,the skin effect is completely suppressed when the gauge potential in each plaquette is equal toπ,while the flat-band localization caused by Aharonov-Bohm caging effect is dominant.By utilizing the indirectly coupled micro ring resonator array,the gauge potential and asymmetric coupling can be generated at the same time,which provides a potential experimental scheme to explore the competition between Aharonov-Bohm cage and skin effect.The present study provides an alternative way to steer the skin effect,which offers an approach to achieving the on-chip non-magnetic unidirectional optical devices.