Vortex laser offers hope for Moore's Law

July 28, 2016 by Cory Nealon
The image above shows vortex laser on a chip. Because the laser beam travels in a corkscrew pattern, encoding information into different vortex twists, it's able to carry 10 times or more the amount of information than that of conventional lasers. Credit: University at Buffalo

Like a whirlpool, a new light-based communication tool carries data in a swift, circular motion.

Described in a study published today (July 28, 2016) by the journal Science, the optics advancement could become a central component of next generation computers designed to handle society's growing demand for information sharing.

It may also be a salve to those fretting over the predicted end of Moore's Law, the idea that researchers will find new ways to continue making computers smaller, faster and cheaper.

"To transfer more data while using less energy, we need to rethink what's inside these machines," says Liang Feng, PhD, assistant professor in the Department of Electrical Engineering at the University at Buffalo's School of Engineering and Applied Sciences, and the study's co-lead author.

The other co-lead author is Natalia M. Litchinitser, PhD, professor of at UB.

Additional authors are: Pei Miao and Zhifeng Zhang, PhD candidates at UB; Jingbo Sun, PhD, assistant research professor of electrical engineering at UB; Wiktor Walasik, PhD, postdoctoral researcher at UB; and Stefano Longhi, PhD, professor at the Polytechnic University of Milan in Italy, and UB graduate students.

A close up look the vortex laser beam. Credit: University at Buffalo.

For decades, researchers have been able to cram evermore components onto silicon-based computer chips. Their success explains why today's smartphones have more computing power than the world's most powerful computers of the 1980s, which cost millions in today's dollars and were the size of a large file cabinet.

But researchers are running into a bottleneck in which existing technology may no longer meet society's demand for data. Predictions vary, but many suggest this could happen within the next five years.

Researchers are addressing the matter in numerous ways including , which uses light to carry information. Examples of optical communications vary from old lighthouses to modern used to watch television and browse the internet.

Lasers are a central part of today's optical communication systems. Researchers have been manipulating lasers in various ways, most commonly by funneling different signals into one path, to carry more information. But these techniques—specifically, wavelength-division multiplexing and time-division multiplexing—are also reaching their limits.

The UB-led research team is pushing laser technology forward using another light manipulation technique called orbital angular momentum, which distributes the laser in a corkscrew pattern with a vortex at the center.

Usually too large to work on today's computers, the UB-led team was able to shrink the vortex laser to the point where it is compatible with computer chips. Because the laser beam travels in a corkscrew pattern, encoding information into different vortex twists, it's able to carry 10 times or more the amount of information than that of conventional lasers, which move linearly.

The vortex laser is one component of many, such as advanced transmitters and receivers, which will ultimately be needed to continue building more powerful computers and datacenters.

Explore further: Laser beams with a 'twist'

More information: P. Miao et al, Orbital angular momentum microlaser, Science (2016). DOI: 10.1126/science.aaf8533

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11 comments

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24volts
1 / 5 (4) Jul 28, 2016
Can someone please explain to me how they get light to travel in circles? I've been seeing this kind of stuff for about 5 years now and still don't have the faintest idea why photons that want to go only in a straight line can do circles. Nor have I found a good explanation anywhere yet.
Eikka
5 / 5 (3) Jul 28, 2016
Researchers are addressing the matter in numerous ways including optical communications, which uses light to carry information.


But that's not in any ways relevant to the Moore's law, which is about the number of transistors on a silicon chip.

Can someone please explain to me how they get light to travel in circles?


It's about circular/elliptical polarization.
epoxy
Jul 28, 2016
This comment has been removed by a moderator.
Eikka
5 / 5 (4) Jul 28, 2016
The light doesn't travel in circles, it rotates its http://i.imgur.com/trwV8qH.gif like screw or Archimedean spiral...


Well, if you search for circular polarization filters, they are literally devices that are physically shaped like spiral staircases. I don't claim to know what it physically means, but the implication is that the photon itself, it's wavefunction or probability density wave or whatever, is indeed travelling in a spiral through space much like a bullet shot through a rifled barrel takes on a spiral path due to the magnus effect.

There's even some papers that describe lasers where one of the mirrors at the end of the tube has been replaced with a spiral element, so that photons that travel in that spiral get through while others get reflected back through the gain medium.
kochevnik
1.8 / 5 (5) Jul 28, 2016
Charged particles all spiral in motion in free space. Planets also spiral through space due to influence of larger bodies
Whydening Gyre
5 / 5 (5) Jul 28, 2016
Charged particles all spiral in motion in free space. Planets also spiral through space due to influence of larger bodies

Add's new meaning the saying about parent's and grandparents, et al, spinning in their graves...:-)
And now you all know... why I chose the screen name I have.l..:-)
24volts
not rated yet Jul 31, 2016
Thanks for the explanation.
Phys1
5 / 5 (1) Jul 31, 2016
It is not about polarisation, it is the wave front that has a spiral form.
A plane wave, which has zero orbital momentum, has a flat wave front.
A wave with non-zero orbital angular momentum has a more complex wave front shape.
viko_mx
1 / 5 (1) Jul 31, 2016
@kochevnik

In the geometric free space can move only abstract geometric objects. Real physical particles the building blocks of matter are moving constantly in real physical medium of the vacuum of comsic space which have physical properties and limitations. The particles interact actively with this physycal medium filling the geometric space of the universe.
epoxy
Jul 31, 2016
This comment has been removed by a moderator.
Phys1
5 / 5 (2) Jul 31, 2016
In any case this is not about SAM.

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