Bikbaev Rashid G, Maksimov Dmitrii N, Pankin Pavel S, Chen Kuo-Ping, Timofeev Ivan V
Opt Express. 2021 Feb 1;29(3):4672-4680. doi: 10.1364/OE.416132.
We investigate optical Tamm states supported by a dielectric grating placed on top of a distributed Bragg reflector. It is found that under certain conditions the Tamm state may become a bound state in the continuum. The bound state, in its turn, induces the effect of critical coupling with the reflectance amplitude reaching an exact zero. We demonstrate that the critical coupling point is located in the core of a vortex of the reflection amplitude gradient in the space of the wavelength and angle of incidence. The emergence of the vortex is explained by the coupled mode theory.
我们研究了置于分布式布拉格反射器顶部的介质光栅所支持的光学塔姆态。结果发现，在某些条件下，塔姆态可能会变成连续谱中的束缚态。反过来，这种束缚态会引发临界耦合效应，反射率幅值达到精确的零值。我们证明，临界耦合点位于波长和入射角空间中反射幅值梯度的涡旋核心处。涡旋的出现由耦合模理论进行了解释。
