Congratulations to fourth-year PGR James Capers, who has just had his paper ‘Designing Disordered Multi-Functional Metamaterials using the Discrete Dipole Approximation’ accepted for publication in New Journal of Physics.
James explains the significance of the paper’s findings:
Being able to manipulate radiation in any desired way is key to sensing, stealth, power transfer and next-generation communications. However, to design a material to manipulate radiation in a particular way, you must specify 36 complex numbers at every single point in space. This huge number of degrees of freedom makes the design of metamaterials extremely challenging. In recent years, many powerful analytical and numerical techniques have emerged to address the problem of designing materials that manipulate radiation however little attention has been paid to the design of multi-functional metamaterials. In this paper, we address this problem and derive a simple, efficient and versatile way to design passive multi-functional structures that might be employed to manipulate antenna radiation. Our proposed technique allows one to design classes of metamaterials that would otherwise be numerically inaccessible and may find application in antenna engineering as well as in the fields of acoustic and elastic metamaterials.
Abstract below:
The ability to design passive structures that perform different operations on different electromagnetic fields is key to many technologies, from beam-steering to optical computing. While many techniques have been developed to optimise structures to achieve specific functionality through inverse design, designing multi-function materials remains challenging. We present a semi-analytic method, based on the discrete dipole approximation, to design multi-functional metamaterials. To demonstrate the generality of our method, we present two key examples. Firstly, we work at optical wavelengths to design a disordered 2D arrangement of silicon spheres that beams light into different directions depending on the source polarisation. Secondly, we design a 3D device that works at microwave wavelengths and sorts plane waves by their angle of incidence. In this case, the scatterers are more complicated meta-atoms, with a strong dipole resonance at microwave frequencies.