Modes of an elliptical cylindrical resonant cavity -- analytical solution

Mode density of orbital angular momentum modes in a cylindrical cavity and in free space

In this short note we derive an approximate expression for the mode density of modes carrying orbital angular momentum (OAM) in a cylindrical cavity which is large compared to the inverse wavevector in any direction. We argue that in the large cavity limit the modes asymptotically converges to the corresponding OAM modes in free space. We compare the result to Weyl's law. It is found, as expected, that the mode density does not depend on whether or not the modes carry OAM.

Coupling cavity model for circular cylindrical waveguide with uniform cross section

We developed the general approach that gives possibility to calculate the coupling coefficients for arbitrary chain of resonators without using the great number of eigen functions. For understanding this method and having possibility to control the accuracy of obtained results, we applied this procedure for simplest structure that has the analytical solutions - a circular cylindrical waveguide with uniform cross section.

Wave Scattering by a Cylindrical Metasurface Cavity of Arbitrary Cross-Section: Theory and Applications

This paper presents a technique, combining the integral equations (IE) and the Generalized Sheet Transition Conditions (GSTCs) with bianisotropic susceptibility tensors, to compute electromagnetic wave scattering by cylindrical metasurfaces -- forming two-dimensional porous cavities -- of arbitrary cross sections. Moreover, it applies this technique to two problems -- cloaking with circular and rhombic shapes and illusion optics with an elliptic shape -- that both validate it, from comparison with specifications used in an exact synthesis of the metasurfaces, and reveal interesting capabilitie…

Optical radiation force (per-length) on an electrically conducting elliptical cylinder having a smooth or ribbed surface

The aim of this work is to develop a formal semi-analytical model using the modal expansion method in cylindrical coordinates to calculate the optical/electromagnetic (EM) radiation force-per-length experienced by an infinitely long electrically-conducting elliptical cylinder having a smooth or wavy/corrugated surface in EM plane progressive waves with different polarizations. One of the semi-axes of the elliptical cylinder coincides with the direction of the incident field. The modal matching method is used to determine the scattering coefficients by matrix inversion. Standard cylindrical (Be…

无奇点隐身衣

Invisibility cloak without singularity

在椭圆柱坐标系中，利用坐标变换将隐身物体压缩为一条直线而不是一个点，提出了一种椭圆隐身斗篷。如果椭圆焦点变得很小，椭圆形斗篷就变成了近似圆形的斗篷。该隐身衣的优点是没有一个参数是奇异的，所有参数的变化范围相对较小。

Analytical treatment of the wakefields driven by transversely shaped beams in a planar slow-wave structure

The suppression of transverse wakefield effects using transversely elliptical drive beams in a planar structure is studied with a simple analytical model that unveils the geometric nature of this phenomenon. By analyzing the suggested model we derive scaling laws for the amplitude of the longitudinal and transverse wake potentials as a function of the Gaussian beam ellipticity - $σ_x/a$. We explicitly show that in a wakefield accelerator application it is beneficial to use highly elliptical beams for mitigating transverse forces while maintaining the accelerating field. We consider two scaling…