arXiv subjects

Rosa Letizia

Publications and source records attributed to Rosa Letizia.

3 recordsLinked to original sources

arXiv2018

Mode profile shaping in wire media: Towards an experimental verification

We show that an experimentally plausible system consisting of a modulated wire medium hosted in a metal cavity can preserve the longitudinal field profile shaping predicted by Boyd et al. (2018) on the basis of a perfectly periodic wire-only structure. These new frequency domain numerical results are a significant step towards justifying the construction of an experimental apparatus to test the field profile shaping in practise.

physics.app-ph↗

arXiv2018

Customized longitudinal electric field profiles: using spatial dispersion in dielectric wire arrays

We show how spatial dispersion can be used as a mechanism to customize the longitudinal profiles of electric fields inside modulated wire media, using a fast and remarkably accurate 1D inhomogeneous model. This customization gives fine control of the sub-wavelength behaviour of the field, as has been achieved recently for transverse fields in simpler slotted-slab media. Our scheme avoids any necessity to run a long series of computationally intensive 3D simulations of specific structures, in order to iteratively converge (or brute-force search) to an empirical `best-performance' design according to an abstract figure-of-merit. Instead, if supplied with an `ideal waveform' profile, we could now calculate how to construct it directly. Notably, and unlike most work on photonic crystal structures, our focus is specifically on the field profiles because of their potential utility, rather than other issues such as band-gap control, and/or transmission and reflection coefficients.

physics.app-ph↗

arXiv2017

Subwavelength Mode Profile Customisation Using Functional Materials

An ability to completely customise the mode profile in an electromagnetic waveguide would be a useful ability. Currently, the transverse mode profile in a waveguide might be varied, but this is usually a side effect of design constraints, or for control of dispersion. In contrast, here we show how to control the longitudinal (propagation direction) mode profile on a sub-wavelength scale, but without the need for active solutions such as synthesizing the shape by combining multiple Fourier harmonics. This is done by means of a customised permittivity variation that can be calculated either directly from the desired mode profile, or as inspired by e.g. the range of shapes generated by the Mathieu functions. For applications such as charged particle beam dynamics, requiring field profile shaping in free space, we show that it is possible to achieve this despite the need to cut a channel through the medium.

physics.optics↗