Generalised Transformation Media

Recently researchers have discovered how to manipulate both light and sound in a 'designer' fashion. This expertise has progressed to the extent that laboratory demonstrations of invisibility cloaks not only already exist, but are improving year on year. Since simple invisibility has almost become mundane for the follower of scientific developments, we have had to reinvent the very notion of what `invisible' means. So rather than making merely objects invisible, we have discovered how to manipulate light in such a way that the objects remain in plain sight whilst selected events involving them are hidden - a 'History Editor'. This means that in principle, things can occur without being detected or suspected, even if under the unwavering gaze of a surveillance camera.

The underlying mathematical idea that led us to these discoveries is that the coordinates used to describe how light travels through space and time are arbitrary. This means that no matter what procedure we choose to follow for recording coordinate times and coordinate locations, the processes that we are describing must look the same. Even if we decide to use curved, distorted, or otherwise transformed coordinates, any light we are describing must still travel in straight lines. However, if I instead insist that the new coordinates be straight, then to compensate, the light rays must appear to travel along curved paths. If we then decide on a useful set of transformed coordinates, perhaps ones defining an invisibility cloak, mathematics can tell us exactly how to design a material so that the light rays are actually curved in the same way. This idea is known as Transformation Optics, and it is one that is exciting researchers the world over. These scientists are now able to design and make a whole host of new optical devices such as 'carpet cloaks', concentrators, or even artificial black holes.

Although Transformation Optics is now quite developed, we want to develop a more general theory called Transformation Media. This will describe how the ideas from Transformation Optics can be made more general and independent of specific areas of physics, such as acoustics, heat diffusion, electromagnetics, and quantum mechanics. This new unified 'Transformation' design tool and mind set will enable a raft of possible applications, from simple but pervasive enhancements to existing device technology, to more novel devices of a type that may even once been thought impossible. These may include, but are not limited to, acoustic black holes and sonar history editing, heat cloaking for firefighters and quantum wave manipulation for nanotechnology.

This research will impact primarily on investigators in a number of disciplines and technologies (e.g. optics, acoustics, thermal engineering). Our proposed precisely coded `how to' recipe for applying a `Transformation Media' algorithm to their specific starting point will enable them to think in new ways. They will then be able to design both enhanced and entirely new types of device, all by using materials with properties tailored by the transformation recipe. Penetration and impact of our research is likely to occur on a timescale of about 5 years, as awareness grows across multiple fields of our new and powerful approach.

We have also thought carefully about how to widen the Impact of our research in `real-time', particularly to schools and the general public, where we believe we have specific expertise and experience:

Schools: The PI has, over the last three years, developed an undergraduate course module called `Communicating Physics'. This optional course for third year undergraduates enables them to spend a few hours each week in the spring term at a school to assist in the teaching of physics, and in encouraging pupils to take their studies further (particularly at Imperial!). This has now developed into an approved 3-year degree programme 'Physics with Science Education', which will graduate students with a fully Institute of Physics accredited physics degree and also confer Qualified Teacher Status. The degree is run jointly with experts in initial teacher training at Canterbury Christ Church University. In the current climate this represents an enormous development towards increasing the number and quality of specialised physics teachers in schools. As a result, we are very well connected with a host of schools and outreach organisations (e.g. the Science Museum). We will use these contacts to deliver regular outreach lectures to schools and other venues and so introduce the ideas and concepts of Transformation Media to aspiring physicists. Indeed, we have just developed an elegant water-wave transformation device called `Maxwell's Fishpond', of an ideal size to use in demonstrations, and which is based on an idea developed by James Clerk Maxwell himself.

Media: Publication of our Spacetime Cloak paper in November 2010 caused a media flurry across the globe, with virtually all major scientific media outlets carrying a brief report of our idea that events, not just objects, can be cloaked. We had to learn very quickly how to deal with reporters, conduct radio and television interviews, and give popular lectures. The Communications Office at Imperial has been exceptionally effective in acting as the professional interface between us as scientists and the wider public. A second wave of publicity is occurring at the time of writing following the publication in Nature of the report from a group at Cornell who have built the first spacetime cloak. The result of all this is that we are now reasonably `media savvy', being familiar with embargo protocols and writing popular press releases, and being well connected to the media machines of our own institution and the Institute of Physics. We now have a good eye for what makes a good story, and so if, for example, our research provides a simple recipe for making a heat cloaking device, we will not only write the paper, but use our experience and contacts to make sure that a brief report appears in appropriate media outlets.