An ultra-broad bandgap plasmonic based filter that consists of a metal-insulator-metal waveguide with symmetrical stubs and defects is designed and investigated for the first time. A tunable wide bandgap can be achieved by introducing the defects into the stubs and a larger bandgap width about 1.35 times compared to its counterpart without defects is acquired. It is found that both the defects and number of periods play the crucial roles to affect the bandgap performance, which is attributed to the change of effective refractive index and plasmon resonance modes in the proposed structure. The proposed plasmonic filter has potential to be a promising alternative structure to realize in integrated optical circuits for optical trapping and tunable devices.

首次设计并研究了一种由带隙对称且具有缺陷的金属-绝缘体-金属波导组成的超宽带隙等离子体基滤波器。通过将缺陷引入到短截线中，可以实现可调节的宽带隙，并且获得的带隙宽度是无缺陷的带隙宽度的约1.35倍。发现缺陷和周期数都对影响带隙性能起着至关重要的作用，这归因于所提出的结构中有效折射率和等离子体激元共振模式的变化。所提出的等离子体滤波器有可能成为在用于光陷波和可调装置的集成光学电路中实现的有希望的替代结构。