Acoustics and Phononics
Prof Alastair Hibbins
Acoustic and elastic metamaterials
Acoustic and elastic metamaterials are composite materials, typically with small resonant inclusions, which have been designed to control, direct, and manipulate sound or mechanical motion. There is a drive towards ever- increased device performance and functionality, and metamaterials offer an opportunity to look beyond naturally-occurring materials since they can be engineered to have completely artificial behaviour.
We investigate the acoustic absorption achieved via structuring of materials; the selective transmission through apertures and phononic crystal structures; the emission of thermally generated sound; the coupling of sound to mechanical vibrations and fluid flow; the excitation of acoustic surface waves for the channelling of sound across surfaces.
Our work is great relevance to end users, particularly those interested in signature control, thin absorbers, noise control, acoustic wave forming and imaging, and energy harvesting.
Prof Geoff Nash
Optical and Acoustic Materials and Devices
Within the NEST group we explore the fascinating characteristics of new materials including 2D materials, for example graphene, and metasurfaces. We both investigate fundamental phenomena, such as the interaction of light with molecules, but also aim to exploit these phenomena to create novel technology.
Prof Sir Roy Sambles
Electromagnetic and acoustic materials
Waves change their speed when going from one material to another - refraction. By structuring materials on the scale of the wavelength of the wave, creating so-called metamaterials, it is possible to create, by design, remarkable effects such as negative refraction or phase speeds approaching infinity. Using microwaves (wavelength of order mms) or sound (wavelength of order cms) it is relatively straightforward to make novel materials with properties not otherwise obtainable. This leads on to potential applications such as perfect radar absorbers or holey screens which allow air through but little sound. Since microwave communications and sound play such vital roles (mobile phones, TVs, radio etc.) in our everyday lives the fundamental research being here undertaken on novel metamaterials may have very significant sociological impact.
Prof Janet Anders
Our research focusses on providing theoretical understanding of thermodynamics at the nanoscale. Specifically, we investigate the importance of small scale fluctuations and non-equilibrium effects within stochastic thermodynamics and investigate the impact quantum effects, such as coherences and entanglement, have on thermodynamic processes.
My work enables a better understanding and manipulation of heat/energy at the nanoscale. I am currently also involved in a project that may, one day, lead to single molecule sensing for diagnostics in the healthcare sector. Previously, I focussed on quantum cryptography which can find applications in communication and security.
Please see the Quantum Group website for more information.
Prof Volodymyr Kruglyak
We study phenomena associated with spin waves (elementary excitations of the magnetic order) and magnons (their quanta). Spin waves carry energy and angular momentum via a collective wave motion of spins. So, the relation between magnonics and the rest of spin physics (aka spintronics) is akin that between the ac and dc electricity. Magnonics offers the perspective of technology that would use spin waves (or magnons) to carry and process both analog signals and digital data. The most attractive features of this technology are the low power, magnetic reconfigurability and scalability to nanometre dimensions.
Prof Francesca Palombo
Biophotonics and Biomechanics
The mechanical properties of biological tissues are central to their function and impairment is implicated in ageing and disease. Changes in the macroscopic mechanical properties and tissue structure and composition are both well characterised, but the causal relationships between them are largely unclear. A novel microscopy technique based on Brillouin light scattering from acoustic waves at GHz frequencies has emerged for the contactless 3D probing of tissue mechanics at the microscopic and subcellular levels. In Exeter we advance the development and applications of Brillouin microscopy as a novel optical technique within biophotonics and the clinical environment.
Senior Lecturers / Senior Research Fellows
Dr David Horsell
Acoustic and thermal devices
We study the generation, control and interaction between sound, heat and electricity in materials. The focus of our experimental research is to study the fundamental physics of acoustic, thermal and electrical transport both within materials and across interfaces between materials. This has direct application in sound production, heat management in electronics, and improved efficiency of electronic devices. We also investigate the ways in which these properties can be used for active sensing, which includes detection of gas and fluids as well as electrical and thermal features of materials. Our work extends into biological systems, including biomimetics, thermoregulation in insects and electrical signalling in plants and animals.
Dr Simon Horsley
Theory of electromagnetic and acoustic materials
Design of electromagnetic materials: Suppose you want to do something to a wave; perhaps redirect a radio wave, or absorb a sound wave. I use mathematics to look for the materials you need.
I am interested in the theory of electromagnetism and wave physics in general. Recently I've been thinking about how waves reflect from metamaterial structures, but I also work on the theory of quantum electromagnetism in dielectric media (I am interested in understanding how macroscopic bodies affect the quantum properties of the electromagnetic field, and how these in turn affect the motion of the object).
Dr Dibin Zhu
Metamaterials for energy harvesting and wireless power transfer
Energy harvesting concerns conversion of unused or wasted energy in the environment into electrical energy to power small electronic devices such as wireless sensors. Exploitation of metamaterials in energy harvesting will enhance coupling between transducers and ambient energy sources to improve its energy conversion efficiency. Furthermore, EM metamaterials can improve directionality of RF signal and thus improve power transmission efficiency of wireless power transfer systems.
Dr Tim Starkey
Acoustic and elastic metamaterials
I’m interested in metamaterials for the control of acoustic and elastic waves, and their application to tailoring fluid flows. My research focusses on experimental, numerical and analytical research methodologies to develop the science and technology underpinning the next generation of acoustic and elastic metamaterials.