介质加载型混合表面等离子体波导的损耗特性

Propagation properties of a dielectric-loaded hybrid surface plasmonic waveguide

为实现长距离传输及亚波长尺度的模式限制,在传统介质加载型表面等离子结构的基础上,设计了一种微孔介质加载混合表面等离子体波导,采用时域有限差分法(FDTD)对该波导模式场分布及传输特性进行了相应的研究。研究表明所设计的波导结构具有较强的局域场限制,通过在孔内填充增益介质,使混合等离子体波导的传输损耗得到了补偿,输出端的表面等离子激元实现了增益放大。结果表明,通过调整波导的几何参数和电磁参数,可以显著提高波导的场限制,降低波导本身的损耗,其中当孔与金属之间距离为44 nm时,波导的损耗达最小约为-13 d B/μm。这一设计可以为光子器件集成提供一定的理论和实验借鉴价值。

In order to realize long propagation distance and achieve subwavelength mode confinement, a dielectric-loaded hybrid surface plasmonics waveguide with a nano-hole was designed, which was based on traditional dielectric-loaded surface plasmonics waveguide. The propagation properties and mode field distributions of this novel hybrid waveguide were studied using finite-difference time-domain（FDTD） method.The results show that the structure could strongly modulate the local field enhancement. Furthermore, the nano-hole was filled with gain medium which leads to a gain enhancement, and the propagation loss could be compensated. In short, adjusting the geometrical parameters can significantly improve the confinement of the SPPs fields and reduce the losses of the waveguide. It also shows that the transmission loss is up to-13 d B/μm in the case of d =44 nm. This surface plasmonics waveguide can be used for subwavelength optical confinement and applied to the field of photonic device integration and sensors.