AI 中文总结
研究介电蝴蝶结纳米腔中光增强现象，揭示其为经典电磁边缘奇点的有限几何实现，阐述尖端半径、间隙和长度的不同作用，通过静电及三维准正常模式模拟证实缩放定律并展示近场机制。
AI 中文摘要
介电蝴蝶结纳米腔可将光集中到亚波长区域，且无等离子体金属的欧姆损耗。我们表明这种增强是经典电磁边缘奇点的有限几何实现。与孤立介电楔不同，蝴蝶结中的缩放由集体四扇区奇点确定的指数控制。在有限结构中，这种无标度奇异场由间隙大小正则化，而蝴蝶结长度设定外部尺度。尖端半径、间隙和蝴蝶结长度因此发挥不同物理作用。静电模拟证实了预测的缩放定律，三维准正常模式模拟展示了现实介电纳米腔如何利用和限制相同的近场机制。
英文摘要
Dielectric bowtie nanocavities can concentrate light into subwavelength regions without the ohmic losses of plasmonic metals. We show that this enhancement is the finite-geometry realization of a classical electromagnetic edge singularity. Unlike an isolated dielectric wedge, the scaling in a bowtie is governed by an exponent determined by a collective four-sector singularity. In a finite structure, this scale-free singular field is regularized by the gap size, while the bowtie length sets the outer scale. The tip radius, gap, and bowtie length therefore play distinct physical roles: curvature cuts off the local wedge singularity, the gap cuts off the collective bowtie singularity, and the outer length sets the range over which the field can build up. Electrostatic simulations confirm the predicted scaling laws, while three-dimensional quasinormal-mode simulations show how the same near-field mechanism is accessed and limited by realistic dielectric nanocavities.
Comments6 pages, 5 figures
