Qi Jiwei, Chen Zongqiang, Chen Jing, Li Yudong, Qiang Wu, Xu Jingjun, Sun Qian
Opt Express. 2014 Jun 16;22(12):14688-95. doi: 10.1364/OE.22.014688.
In this paper, an asymmetric plasmonic structure composed of a MIM (metal-insulator-metal) waveguide and a rectangular cavity is reported, which can support double Fano resonances originating from two different mechanisms. One of Fano resonance originates from the interference between a horizontal and a vertical resonance in the rectangular cavity. And the other is induced by the asymmetry of the plasmonic structure. Just because the double Fano resonances originate from two different mechanisms, each Fano resonance can be well tuned independently by changing the parameters of the rectangular cavity. And during the tuning process, the FOMs (figure of merit) of both the Fano resonances can keep unchanged almost with large values, both larger than 650. Such, the transmission spectra of the plasmonic structure can be well modulated to form transmission window with the position and the full width at half maximum (FWHM) can be tuned freely, which is useful for the applications in sensors, nonlinear and slow-light devices.
本文报道了一种由金属-绝缘体-金属(MIM)波导和矩形腔组成的非对称等离子体结构,该结构可支持源于两种不同机制的双Fano共振。其中一种Fano共振源于矩形腔内水平共振和垂直共振之间的干涉。另一种则由等离子体结构的不对称性引起。正是由于双Fano共振源于两种不同机制,通过改变矩形腔的参数,每个Fano共振都可以独立地得到很好的调谐。并且在调谐过程中,两个Fano共振的品质因数(FOM)几乎可以保持不变且具有较大的值,均大于650。因此,等离子体结构的透射光谱可以得到很好的调制,从而形成透射窗口,其位置和半高宽(FWHM)可以自由调谐,这对于传感器、非线性和慢光器件中的应用很有用。