How metamaterials bend reality: from earthquake shields to lab-grown black holes

Sir John Pendry’s lecture showed how engineered materials make sci-fi real, from invisibility cloaks to microscopes revealing the nanoscopic world.

Sir John Pendry is a Professor of Theoretical Solid-State Physics at the Department of Physics. As part of Imperial College London’s annual Frontiers in Natural Sciences: Dean's Annual Lecture, Sir Pendry presented his pioneering research into metamaterials – engineered materials that allow unprecedented control over electromagnetic waves.

Drawing from decades of research, Sir Pendry explored how metamaterials challenge the limits of traditional optics and open new possibilities for manipulating light, with applications ranging from super-resolution imaging to energy-efficient cooling and advanced communication technologies.

A new world for electromagnetism

“As far as light and electromagnetism are concerned, there is a shortage of the sort of materials that we may want to have,” Sir Pendry said, “There are many things in optics which we know in principle we should be able to do, but we cannot do because there are no materials available.”

As far as light and electromagnetism are concerned, there is a shortage of the sort of materials that we may want to have... Sir John Pendry Department of Physics

In his lecture, Sir Pendry described how conventional materials derive their properties from the atomic structure of their constituents. However, by designing materials at the nanoscale – structuring them rather than relying on chemical composition – scientists can create entirely new optical properties.

Metamaterials are designed to interact with electromagnetic waves in ways that do not occur in nature. One of their most remarkable properties is negative refraction, an optical effect that was first predicted by Russian physicist Victor Veselago in 1968 that Pendry helped realise experimentally.

This discovery led to the discovery of the perfect lens. Conventional lenses are limited because they cannot see things smaller than the wavelength of light that reflect off them.

However, Sir Pendry demonstrated that a lens made from a negatively refracting material could overcome this limit, perfectly reconstructing details that are smaller than the wavelength of light we use to see them.

Metamaterials can also be engineered to manipulate the paths of electromagnetic waves in ways that mimic celestial bodies which are so massive that they can curve the trajectory of light itself.

Metamaterials can similarly distort the paths of light rays to cloak objects from radar or visible light, rendering them invisible. The same principles may also one day shield buildings from earthquakes.

Any and all waves

Sir Pendry hinted at the next frontier in metamaterials research: the structuring of materials not just in space, but in time. By altering a material’s properties at ultrafast timescales, scientists can not only manipulate the direction of waves but also their energies or frequencies.

If you structure materials in time, you can enter a new world Sir John Pendry Department of Physics

"If you structure materials in time, you can enter a new world," he said. "Energy isn’t conserved, and you can amplify light. Some of these structures, in which you can induce a singularity, have similarities with the singularity in a black hole.”

Metamaterials are disrupting fields of research outside of optics, such as acoustics and even the study of water waves.

Those who attended the lecture could see a few of the novel applications of metamaterials in a research showcase that took place in the Queen’s Tower Rooms afterwards, which had displays that used metamaterials in neuromorphic computing and even an augmented reality demo from Snapchat.

If you missed the lecture, a recording of it is available on Youtube.