Light-powered computers would work millions of times faster. (Reuters)


Scientists can now “squeeze” light, a breakthrough that could make computers millions of times faster

We are now one step closer to ultra-fast, light-based computers.

by Olivia Goldhill


Have you ever wondered why we don’t use light to transmit messages? Nothing can travel faster than the speed of light, but while we use light to carry signals along fiber optic cables, we use electrons to process sound and information in our phones and computers. The reason has always been because light particles–photons—are extremely difficult to manipulate, whereas electrons can be manipulated relatively easily.

But now a group of Harvard physicists has taken a major step toward solving that puzzle, and have brought us one step closer to ultra-fast, light-based computers.

The physicists, led by Professor Eric Mazur, have created a material where the phase velocity of light is infinite. Their results were published in Nature Photonics on Oct. 19th.

“The phase speed is infinite—much larger, infinitely larger than the speed of light,” Mazur tells Quartz.

This doesn’t mean light itself is traveling faster than the speed of light, which would violate the laws of relativity. “Phase velocity” refers to the speed of the crest of waves that ripple out when light strikes a material. The Harvard scientists created a material that allows these wave crests to move infinitely fast. This is a strange thought to wrap your head around, and means the crests of the waves are oscillating through time, but not space. Under these peculiar conditions, the Harvard scientists found that it’s easy to manipulate the photons, squeezing them down to the microscopic scale and turning them around. In other words, we can treat photons in the same way we currently manipulate electrons.

And it’s electromagnetic waves that count when it comes to telecommunications.

“These waves are everywhere,” says Mazur. “We can talk on mobile phones because, in our phones, there are electrons that move up and down to create a wave. This wave travels to the antennae of the phone company and makes electrons there move up and down, which can be detected and turned into electrical signals that can be turned into an audio signal.”

That means the potential commercial uses for this discovery are massive. We won’t see light-based computers yet, as there are still several obstacles to address, but Mazur and his team have overcome a key challenge. “Usually, light needs to be handled very carefully and squeezed very slowly,” says Mazur. “With our material, you relax those constraints completely. You can bend the light, squeeze it, twist it.”

Light-powered telecommunications would allow phones and computers to process information millions of times faster. And because light conserves energy far better than electrons (which tend to waste energy by creating heat), battery lives would be far longer.

It may seem that we already transmit communications pretty fast. But if we could use light to process messages, everything would get a whole lot faster.

  Source: Quartz





Harvard scientists invent chip that squeezes light

Physicists from Harvard University have succeeded in creating a new type of optical chip that is able to control light so that it flows infinitely faster than the speed of light, which could eventually pave the way for superfast light-based quantum computers.


Scientists ‘squeeze’ light one particle at a time:

A team of scientists has successfully measured particles of light being “squeezed”, in an experiment that had been written off in physics textbooks as impossible to observe.

Squeezing is a strange phenomenon of quantum physics. It creates a very specific form of light which is “low-noise” and is potentially useful in technology designed to pick up faint signals, such as the detection of gravitational waves.

The standard approach to squeezing light involves firing an intense laser beam at a material, usually a non-linear crystal, which produces the desired effect.

For more than 30 years, however, a theory has existed about another possible technique. This involves exciting a single atom with just a tiny amount of light. The theory states that the light scattered by this atom should, similarly, be squeezed.

Unfortunately, although the mathematical basis for this method – known as squeezing of resonance fluorescence – was drawn up in 1981, the experiment to observe it was so difficult that one established quantum physics textbook despairingly concludes: “It seems hopeless to measure it”.

So it has proven – until now. In the journal Nature, a team of physicists report that they have successfully demonstrated the squeezing of individual light particles, or photons, using an artificially constructed atom, known as a semiconductor quantum dot. Thanks to the enhanced optical properties of this system and the technique used to make the measurements, they were able to observe the light as it was scattered, and proved that it had indeed been squeezed.