Engineers make sound loud enough to bend light on a computer chip

November 26, 2014
University of Minnesota engineers make sound loud enough to bend light on a computer chip
The figure illustrates a sound wave passing across an integrated optical waveguide, overlaid with a color map of the light field in it. Credit: University of Minnesota

During a thunderstorm, we all know that it is common to hear thunder after we see the lightning. That's because sound travels much slower (768 miles per hour) than light (670,000,000 miles per hour).

Now, University of Minnesota engineering researchers have developed a chip on which both and are generated and confined together so that the sound can very efficiently control the light. The novel device platform could improve using optical fibers and ultimately be used for computation using .

The research was recently published in Nature Communications.

The University of Minnesota chip is made with a silicon base coated with a layer of aluminum nitride that conducts an electric change. Applying alternating electrical signal to the material causes the material to deform periodically and generate sound waves that grow on its surface, similar to that grow from the center of the earthquake. The technology has been widely used in cell phones and other wireless devices as microwave filters.

"Our breakthrough is to integrate optical circuits in the same layer of material with acoustic devices in order to attain extreme strong interaction between light and sound waves," said Mo Li, assistant professor in the Department of Electrical and Computer Engineering and the lead researcher of the study.

The researchers used the state-of-the-art nanofabrication technology to make arrays of electrodes with a width of only 100 nanometers (0.00001 centimeters) to excite sound waves at an unprecedented high frequency that is higher than 10 GHz, the frequency used for satellite communications.

"What's remarkable is that at this high frequency, the wavelength of the sound is even shorter than the wavelength of light. This is achieved for the first time on a chip," said Semere Tadesse, a graduate student in the University of Minnesota's School of Physics and Astronomy and the first author of the paper. "In this unprecedented regime, sound can interact with light most efficiently to achieve high-speed modulation."

In addition to applications in communications, researchers are pursuing quantum physics applications for the . They are investigating the interaction between single photons (the fundamental quantum unit of light) and single phonons (the fundamental quantum unit of sound). The researcher plan to use sound waves as the information carriers for quantum computing.

Explore further: Quantum microphone captures extremely weak sound

More information: "Sub-optical wavelength acoustic wave modulation of integrated photonic resonators at microwave frequencies," Nature Communications, 2014. www.nature.com/ncomms/2014/141117/ncomms6402/full/ncomms6402.html

Related Stories

Quantum microphone captures extremely weak sound

February 6, 2012

(PhysOrg.com) -- Scientists from Chalmers have demonstrated a new kind of detector for sound at the level of quietness of quantum mechanics. The result offers prospects of a new class of quantum hybrid circuits that mix acoustic ...

Probing the sound of a quantum dot

April 24, 2014

(Phys.org) —Physicists at the University of Sydney have discovered a method of using microwaves to probe the sounds of a quantum dot, a promising platform for building a quantum computer.

The sound of an atom has been captured

September 11, 2014

Researchers at Chalmers University of Technology are first to show the use of sound to communicate with an artificial atom. They can thereby demonstrate phenomena from quantum physics with sound taking on the role of light. ...

Subwavelength optical fibers to diffuse light

October 27, 2014

Researchers at the Femto-ST Institute, working in collaboration with colleagues from the Charles Fabry Laboratory (CNRS/Institut d'Optique Graduate School), have just discovered a new type of light diffusion in tiny optical ...

Engineers efficiently 'mix' light at the nanoscale

November 13, 2014

The race to make computer components smaller and faster and use less power is pushing the limits of the properties of electrons in a material. Photonic systems could eventually replace electronic ones, but the fundamentals ...

Recommended for you

Color-changing water reflects a rainbow of colors and beyond

September 21, 2016

(Phys.org)—Scientists have created a water-based mixture that rapidly changes color when exposed to a variety of stimuli, such as a change in magnetic field, temperature, or pH. The scientists call the mixture "photonic ...

14 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

jerryjbrown
2 / 5 (2) Nov 26, 2014
approximately ~768 mph (in air)..........please be specific about the approximation on a science site!
Basilioexablm CASTLE
3 / 5 (3) Nov 26, 2014
Also on a science website use SI units and do not call me commie our Military is metric too. Is only Joe Blow that needs miles and feet or even the Biblical cubits.
Ben D
1 / 5 (5) Nov 26, 2014
"... the wavelength of the sound is even shorter than the wavelength of light."
----------------------------------------------------------------------------------------------------
That's B/S..wave lengths shorter than light are ultra violet waves, not sound waves.
Sound waves are by definition less than 20 Khz...end of story. That mixing and upconverting processes can raise higher frequencies is not new....but to then claim these higher frequencies are of the same band as the original is just bad journalism!
Bob Osaka
3 / 5 (2) Nov 26, 2014
Hate to join the dog pile but a thousand paces of a Roman legionnaire is no longer an applicable unit of measure. Unless prepared to sell the world on the nanoinch, please stick to SI units.
adam_russell_9615
1 / 5 (4) Nov 26, 2014
If metric is so good then why hasnt metric time units ever caught on?
Because the change would be inconvenient - same reason US doesnt adopt kilometers for freeways.
grondilu
3 / 5 (2) Nov 27, 2014
> If metric is so good then why hasnt metric time units ever caught on?

It kind of has. I mean, even if in this article there is a speed expressed in mph, there is also a distance expressed in nm, and a frequency in GHz. That's SI.
_etabeta_
3 / 5 (2) Nov 27, 2014
Shame on anybody still using imperial units in science. In 1999 $125 million went up in smoke (NASA's Mars Climate Orbiter) because of this idiocy. Only 3 countries still use this backward crap: Liberia...Myanmar...and the USA. It's about time to STOP this!.
alfie_null
4.2 / 5 (5) Nov 27, 2014
If metric is so good then why hasnt metric time units ever caught on?
Because the change would be inconvenient - same reason US doesnt adopt kilometers for freeways.

Back in the 1970s, we were lurching our way towards metrication. Killed by Reagan. Allegedly to reduce federal spending, and because the electorate was whinging about it. Although that said, we complain loudly about Daylight Savings, yet it lingers.

We had gone so far as to update federal highway signs with dual imperial/metric versions. Subsequently re-replaced at who knows what cost.
Whydening Gyre
1 / 5 (1) Nov 27, 2014
If metric is so good then why hasnt metric time units ever caught on?
Because the change would be inconvenient - same reason US doesnt adopt kilometers for freeways.

Back in the 1970s, we were lurching our way towards metrication. Killed by Reagan. Allegedly to reduce federal spending, and because the electorate was whinging about it. Although that said, we complain loudly about Daylight Savings, yet it lingers.

We had gone so far as to update federal highway signs with dual imperial/metric versions. Subsequently re-replaced at who knows what cost.

because somebodies brother in law owns sign making company...
kochevnik
5 / 5 (3) Nov 27, 2014
@Ben D That's B/S..wave lengths shorter than light are ultra violet waves, not sound waves.
Are you confusing photons with phonons?
robert_inventor
5 / 5 (1) Nov 27, 2014
Took a moment to "get it" when I first read this, so maybe this will help others. So:

wavelength = speed of propogation divided by frequency. Higher frequency = shorter waves. And visible light is THz so a trillion times faster than typical audible sounds.

So then:

Light has frequency about a trillion times that of normal sound, about 430 trillion Hz ranging to 790 trillion Hz

But the speed of light is very roughly a million times that of sound. (300 million meters per second instead of 340 meters per second).

So to get you sounds with wavelength similar to light you need to have them a millionth of that frequency, actually, about 380 megahertz upwards.

So the 10 GHz is easily high enough frequency for sub-visible light wavelengths.
Ben D
not rated yet Nov 27, 2014
Took a moment to "get it" when I first read this, so maybe this will help others. So:

wavelength = speed of propogation divided by frequency. Higher frequency = shorter waves. And visible light is THz so a trillion times faster than typical audible sounds.

So then:

Light has frequency about a trillion times that of normal sound, about 430 trillion Hz ranging to 790 trillion Hz

But the speed of light is very roughly a million times that of sound. (300 million meters per second instead of 340 meters per second).

So to get you sounds with wavelength similar to light you need to have them a millionth of that frequency, actually, about 380 megahertz upwards.

So the 10 GHz is easily high enough frequency for sub-visible light wavelengths.

Thank you Robert...missed that. But my point is still valid imo...the sound waves have been upconverted to the 10 Ghz X band...and thus can no longer be referred to as sound waves
Ben D
not rated yet Nov 27, 2014
@Ben D That's B/S..wave lengths shorter than light are ultra violet waves, not sound waves.
Are you confusing photons with phonons?
How is that relevant to what was said?
adam_russell_9615
not rated yet Nov 28, 2014
If metric is so good then why hasnt metric time units ever caught on?
Because the change would be inconvenient - same reason US doesnt adopt kilometers for freeways.

Back in the 1970s, we were lurching our way towards metrication. Killed by Reagan. Allegedly to reduce federal spending, and because the electorate was whinging about it. Although that said, we complain loudly about Daylight Savings, yet it lingers.

We had gone so far as to update federal highway signs with dual imperial/metric versions. Subsequently re-replaced at who knows what cost.


I guess you missed the point.
Non-Americans like to mock us for not adopting metric freeway signs - because the change was not convenient.
And at the same time the rest of the world was offered metric time units and did not convert - because the change was not convenient.

Just to be crystal clear - it was not that metric time was not useful, but just that it would be too difficult to make the change.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.