The Russian scientist Victor Veselago belonged to the great tradition of physicists who could imagine the nature of things long before his peers saw it with their eyes. In the 1960s, he predicted that we would one day make materials that could bend light in “unnatural” ways, even making it flow backwards.

Such materials were not merely for fun; they could change technology in unprecedented ways. Veselago searched in vain for that material. Forty years later, his extraordinary insight is turning into reality, as physicists keep making materials that force light to behave in ways counter to our intuition.

Recently, scientists at the University of Stuttgart in Germany made a slab of material that could persuade light to go around it, without reflection or refraction. In a layperson’s terms, this means the object would be invisible, making it a “cloaking device”.

Their work came within a year of another cloaking device, using microwaves, made by scientists at the Duke University in the US. Recent computer simulations at the University of Liverpool have shown that it is indeed possible to make objects such as planes invisible. One day, we could even make human beings invisible, but engineers are looking at more immediate uses of these materials, now known as metamaterials.

Metamaterials are useful not just in making things invisible. They could soon let us make super lenses, which could be used in all kinds of optical devices. We could then see into the microscopic world like never before. They could help in etching tiny integrated circuits, thus helping develop faster computers, and developing antennas that could use light instead of electricity and thus lead to faster communications. Metamaterials can help us develop super storage devices. They can be used in imaging technology, and several other applications of the modern world.

A metamaterial is difficult to develop, but very simple to describe. All materials, if they are transparent, bend light rays that pass through them.

All normal materials bend the light towards an imaginary perpendicular line drawn to the surface of the material. In technical terms, these materials have a positive refractive index. A metamaterial bends light away from the perpendicular — that is, it has a negative refractive index. This is the core of the stuff, although metamaterials have some more attributes that are more complicated to describe.

After Veselago’s prediction, scientists had been trying hard to make metamaterials. The crucial insight came in the early 1990s when scientists realised that a metamaterial need not be one material. They could be several materials stacked together but behaving as one. The stacking, however, is on a nanoscale. The structures are smaller than the wavelength of light, and the material behaves as if it were one.

The first metamaterial was made in the year 2000. So far, many research groups around the world have fabricated several kinds of metamaterials.

The super lens is one of the most widely anticipated applications of metamaterials. All objects produce two kinds of optical fields: the far field and the near field. The fine details of the object are in the near field, but it decays very fast. Normal lenses, no matter how powerful, cannot capture the near field. But lenses made of metamaterials can capture the near field, thus letting us see objects in extraordinary detail. Scientists at the University of California in Berkeley have been able to see, using metamaterials, two lines etched 150 nanometres apart. Even the most powerful microscopes can see it only as one line.

So far, scientists have been able to work with metamaterials at wavelengths smaller than visible light. Last year, Duke University scientists stunned the world by demonstrating the “cloaking effect” using microwaves. Now physicists at Stuttgart University have demonstrated the same effect using normal light.

The next few years could see significant breakthroughs in this field, which could change the technological landscape. Will metamaterials be able to make things invisible? The question is no longer in the realm of science fiction.