Nearly bound states in the radiation continuum in a circular array of dielectric rods
Nearly bound states in the radiation continuum in a circular array of dielectric rods
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DOI：
10.1103/physreva.97.033834
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发表时间：
2018-03-16
影响因子：
2.9
通讯作者：
Sadreev, Almas F.
中科院分区：
文献类型：
--
作者：
Bulgakov, Evgeny N.;Sadreev, Almas F.
本文研究了N个无限长介质棒组成的圆形周期阵列中辐射连续区（BIC）中的E极化束缚态。我们发现，每一个真正的BIC出现在一个无限大的线性阵列有其对应的圆阵列作为一个近BIC具有极大的品质因数。我们认为，分析以及数值的质量因子的保护的近BIC发散为e（λ N），其中λ是一个材料参数依赖于半径和折射率的棒。通过调节棒的半径，我们还发现了数值非对称保护的近BIC。这些近BIC以指数精度定位在圆形阵列外部，但填充了携带轨道角动量的阵列的整个内部空间。
We consider E-polarized bound states in the radiation continuum (BICs) in circular periodical arrays of N infinitely long dielectric rods. We find that each true BICwhich occurs in an infinite linear array has its counterpart in the circular array as a near-BIC with extremely large quality factor. We argue analytically as well as numerically that the quality factor of the symmetry-protected near-BICs diverges as e(lambda N), where lambda is a material parameter dependent on the radius and the refraction index of the rods. By tuning of the radius of rods, we also find numerically non-symmetry-protected near-BICs. These near-BICs are localized with exponential accuracy outside the circular array, but fill the whole inner space of the array carrying orbital angular momentum.