The ability to manipulate the interaction between light and optical emitters is essential for enhancing the capability of optical devices. Multifarious metallic and all-dielectric structures have been proposed frequently to enhance the emission of electromagnetic dipoles through the Purcell effect, in which its performances depend on two confinement mechanisms: temporal confinement (photon cavity period) and spatial confinement (localized light in an enclosed space), which can be described by the quality factor and mode volume, respectively. Here, we demonstrate that a hollow spoof plasmonic spiral structure in deep-subwavelength scale, which is constituted by periodically inserting spiral-shaped metallic arms into a hollow silicon cylinder, can drastically enhance emission of magnetic dipoles. Particularly, ultrahigh quality factor and ultrasmall mode volume of the magnetic resonance can be realized by further increasing the spiral degree of metallic arms. The results indicate that the quality factor of magnetic dipole mode in the structure can be enhanced to 2600 (silicon $\sim{5.5}$ for same scale) for spiral degree ${4}\pi $, and the Purcell factor can be enhanced to ${5} \times {{10}^6}$ (silicon $\sim{5.1}$) for a magnetic dipole emission. These results may provide a new avenue for designing optical cavities and enhancing magnetic dipole emission in low frequency.

中文翻译：

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具有欺骗等离子体激元螺旋结构的磁偶极子发射的强大赛尔效应

操纵光和光发射器之间的相互作用的能力对于增强光学设备的能力至关重要。经常提出多种金属和全介电结构以通过珀塞尔效应增强电磁偶极子的发射，其性能取决于两个限制机制：时间限制（光子腔周期）和空间限制（封闭空间中的局部光） ），可以分别通过品质因数和模式音量来描述。在这里，我们证明了通过将螺旋形金属臂定期插入空心硅圆柱体中而构成的深亚波长尺度的空心欺骗等离子体螺旋结构，可以极大地增强磁偶极子的发射。特别，可以通过进一步增加金属臂的螺旋度来实现超高品质因数和超小体积的磁共振。结果表明，结构中的磁偶极子模式的品质因数可以提高到2600（硅$ \ sim {5.5} $（相同比例）对于螺旋度$ {4} \ pi $，并且赛尔系数可以提高到$ {5} \ times {{10} ^ 6} $（硅$ \ sim { 5.1} $）用于磁偶极子发射。这些结果可能为设计光腔和增强低频磁偶极子发射提供一条新途径。