The accurate calculation of guided electromagnetic modes in optical nanofibres is critical for applications in nanophotonics, from quantum interfaces to vectorial light sensing. Standard textbook methods rely on solving a $4\times4$ matrix eigenvalue problem to find the modal fields. While widely used, this approach has a subtle but significant flaw: the final determination of the field amplitudes requires finding the numerical null space of a theoretically singular matrix, an ill-conditioned problem that introduces large relative errors in the small but physically crucial longitudinal field components. In this work, we introduce a fundamentally more robust and efficient semi-analytical method. By starting from the foundational symmetries of the cylindrical waveguide and employing a judicious normalisation of the field amplitudes, we demonstrate that the problem can be analytically reduced to a much simpler $2\times2$ system. This reformulation yields two decisive advantages: the dispersion relation is obtained numerically from a simple and well-behaved transcendental equation, and more importantly, the modal field amplitudes are subsequently determined \emph{analytically}. Our approach completely bypasses the numerical null space calculation, thereby ensuring the accuracy of the full vectorial field structure. This method provides a powerful and reliable tool for the design and analysis of nanofibre-based devices, particularly for applications in chiral quantum optics and nanophotonics where precise knowledge of field polarisation and specifically of the longitudinal components is paramount.
Radiation processes in dielectric cylindrical waveguides
Yerevan State University（耶烈万国立大学）；Institute of Physics, Yerevan State University（耶烈万国立大学物理研究所）；Institute of Applied Problems of Physics NAS RA（亚美尼亚国家科学院应用物理问题研究所）
Full-wave simulations of electromagnetic cloaking structures
基于坐标变换方法，Pendry { \it et al.}已经报道了电磁各向异性和非均匀壳，理论上，其完全屏蔽任意尺寸的内部结构免受电磁场的影响，而不扰动外部场。我们报告全波模拟的圆柱形版本的这种隐身结构，使用理想和非理想的（但物理上可实现的）电磁参数，努力了解在实践中实现这样的结构的挑战。仿真结果表明，电磁隐身结构的性能是不是特别敏感，适度的介电常数和磁导率的变化。这与工程电磁材料的其他应用相反，例如使用负折射率材料的亚波长聚焦。隐身性能随着损耗的增加而平滑地降低，并且可以利用由理想连续介质的八层（均匀）近似组成的圆柱形壳体来实现有效的低反射屏蔽。
Electromagnetic cloaking of cylindrical objects by multilayer or uniform dielectric claddings
我们表明，介电，甚至完全导电的圆柱体可以通过均匀或分层的电介质包覆，而不需要任何外来的或磁性材料的参数。特别是，我们首先提出了一个简单的分析概念，可以准确地描述在可见光谱中的锥形银盘获得的隐身效果。模型结构最初在[S. A. Tretyakov，P. Alitalo，O.卢科宁角R. Simovski，Phys. Rev. Lett. Vol.103，p.103905，2009]，其中仅数值地研究了其在光学频率中作为斗篷的操作。我们严格地模拟这种配置作为一个多层介质覆盖周围的隐形物体，与实际设备的模拟结果非常吻合。使用均匀或多层介质覆盖的概念，相对介电常数大于1，然后成功地扩展到不可穿透的对象，如导电圆柱体的隐身。
Electromagnetic binding and radiation force reversal on a pair of electrically conducting cylinders of arbitrary geometrical cross-section with smooth and corrugated surfaces
