光瞳滤波器是一种重要的调控焦点处光强分布的器件。借助光的标量衍射理论，研究了不同的入射光场分布对超分辨光瞳滤波器的超分辨性能和焦深的影响。研究结果表明：在入射总光能相同的情况下，光场以高斯函数分布入射时，与均匀光入射相比，其超分辨性能和焦深扩展特性变化很小。当光场以零阶贝塞尔函数分布入射时，光斑压缩比基本不变，斯特雷尔比有所下降，焦深有一定扩展。当光场以一阶贝塞尔函数分布入射时，光斑压缩比有所减小，斯特雷尔比有较大提高，焦深有所减小。总之，在相同情况下，光束的光强分布越靠近边缘，越有利于实现超分辨，斯特雷尔比和焦深两个量中其中一个的增大以另一个的减小为代价。

We propose new types of hybrid plasmonic waveguides for low-threshold nanolaser applications. Modal properties and lasing threshold under different geometric shapes and parameters are investigated and -analyzed by the finite element method, aiming to realize both low propagation and high field confinement. Results show that a smaller gap width and a larger round corner radius of the metal film reduce the lasing threshold. These new structures can open up new avenues in the fields of active plasmonic circuits.

We propose and analyze a long-range dielectric-loaded surface plasmon polariton (SPP) waveguide based on graded-index ridge over server millimeter distances. Then the influence of the dielectric thickness and the ridge refractive index on propagation length and mode width is discussed and simulated with the finite ele-ment method. The result shows that the SPP can propagate as long as 3.42 mm, as well as the mode width keeping as 1.64 mm, a better one compared with the fixed refractive index. Considering its nanoscale dimen-sion and outstanding performance, the structure is easily realized when connected with electrodes.