Breakthrough wave scattering method could bring invisibility cloak closer to reality

A new software that simulates complex wave scattering for metamaterial design could bring the invisibility cloak a step closer to reality.

Developed by researchers at Macquarie University, the software can accurately model the way waves – sound, water, or light – are scattered when they meet complex configurations of particles.

The development will vastly improve the ability to rapidly design metamaterials – exciting artificial materials used to amplify, block, or deflect waves.

TMATSOLVER makes it easy to simulate arrangements of scatterers

Researchers have addressed the challenge of rapidly simulating multiple scattering processes in metamaterials. They developed a general formulation of the multiple scattering problem that can simply and easily describe typical metamaterial structures while facilitating efficient implementation of the multipole-based self-consistent method.

Their formulation is implemented in the TMATSOLVER software, which provides a tool for researchers working on metamaterials to prototype their metamaterial designs or validate numerical methods quickly and easily, according to the study.

The research demonstrated the use of TMATSOLVER – a multipole-based tool that models interactions between waves and particles of various shapes and properties.

Published in the journal Proceedings of the Royal Society A, the study claims that the TMATSOLVER software makes it quite easy to simulate arrangements of up to several hundred scatterers, even when they have complex shapes.

The software uses the transition matrix (T-matrix) – a grid of numbers that fully describes how a certain object scatters waves.

Accurately computing T-matrix for particles larger than wavelength

Dr Hawkins, lead author from Macquarie University’s Department of Mathematics and Statistics, stated that the T-matrix has been used since the 1960s, but researchers have made a big step forward in accurately computing the T-matrix for particles much larger than the wavelength, and with complex shapes.

“Using TMATSOLVER, we have been able to model configurations of particles that could previously not be addressed,” added Hawkins.

The software’s capabilities were demonstrated through four example problems in metamaterial design. These problems included arrays of anisotropic particles, high-contrast square particles, and tunable periodic structures that slow down waves.

Metamaterials are designed to have unique properties not found in nature, letting them interact with electromagnetic, sound or other waves by controlling the size, shape and arrangement of their nanoscale structures, according to researchers .

Examples include super-lenses to view objects at the molecular scale; invisibility cloaks, which refract all visible light; and perfect wave absorption for energy harvesting or noise reduction.

Researchers claimed that the findings from this research and development of the TMATSOLVER tool will have wide applications in accelerating research and development in the growing global market for metamaterials, which can be designed for precise wave control.

Dr Hawkins claimed that the study has shown that software can compute the T-matrix for a very wide range of particles, using the techniques most appropriate for the type of particle.

He believes this will enable rapid prototyping and validation of new metamaterial designs.

“The software could accelerate new breakthroughs. This research represents a big leap forward in our ability to design and simulate complex metamaterials,” said Professor Lucy Marshall, Executive Dean, Faculty of Science and Engineering at Macquarie University.

“The study is a prime example of how innovative computational methods can drive advancements in materials science and engineering.”