为了实现高Q值极小模体积的表面等离子体微腔,提出一种混合表面等离子体微盘腔,介质微盘上放置横截面为矩形的金属纳米环形条,微盘腔中间由低折射率材料隔离.用有限元法对混合微腔的模式特性进行数值模拟,研究了其品质因子、有效模式体积和腔外能量比随器件几何尺寸的变化规律.结果表明,所设计微盘腔具有较低的传播损耗、较强的光场约束能力和较高的腔外能量比,品质因子高达7 000,最小模体积仅为0.315 μm3,可实现高灵敏度折射率传感.

A hybrid plasmonic microcavity consisting of a silicon microdisk which is separated from a silver toroidal strip by a low-permittivity dielectric is proposed to achieve high quality factor as well as small mode volume.Mode properties such as quality factor,effective mode volume and energy ratio have been investigated by employing a finite element method and analyzed considering the different structure geometry.Simulation results reveal that this kind of hybrid microcavity maintains low propagation loss with high quality factor ~ 7000,high field limits with small mode volume 0.315 μm3,high energy ratio and can realize a refractive index sensor with high sensitivity.