Skip to comments.Putting Photons to Work
Posted on 05/18/2009 1:13:20 AM PDT by neverdem
Nano vibrator. A tiny device called a zipper cavity can convert laser light into mechanical energy.
Credit: Matt Eichenfield and Jasper Chan, Nature
Researchers have built a nanoscale device that vibrates when struck by incoming laser light. The contraption, which is sensitive to the energy of a single photon, could speed the development of new optical communications systems. It could also help scientists probe some of the fundamental properties of matter with greater precision.
Light beams might not seem capable of performing mechanical work (photons, the carriers of light waves, have no mass), but at the atomic level they can accomplish a surprising amount. For instance, scientists have used laser light to trap, hold, and manipulate individual atoms. The question has been whether the same principle works at the nano scale, at which components are much larger than atoms but still only billionths of a meter in size.
That's what a team from the California Institute of Technology (Caltech) in Pasadena set out to answer. First, the researchers fabricated a pair of planks only a few hundred nanometers wide out of silicon microchip material. Then they chemically etched a series of holes in each of them. The team calls the device a "zipper cavity," because of its resemblance to a zipper (see image). As the researchers report this week in Nature, the holes channel and capture a laser beam's energy and the device vibrates. The frequency of the vibrations depends on the intensity of the laser light bombarding it, says physicist and co-author Oskar Painter of Caltech.
The device behaves like an audio speaker, whose membrane vibrates depending on the intensity of an incoming electronic signal delivered by an amplifier. Conversely, like a microphone, the zipper cavity can modify the light's intensity via its vibrations. Together, the effects enable the zipper cavity to act as a tiny radio transmitter or receiver controlled entirely by light, says Painter, but with much greater range than a similarly sized electronic device.
Physicist Tobias Kippenberg of the Max Planck Institute for Quantum Optics in Garching, Germany, says that scientists could use such nanoscale devices to explore the behavior of matter at the quantum scale, at which electronic devices are unusable. Painter explains that because the device's vibrations occur on the order of 10 million to 150 million cycles per second, it could greatly improve the resolving power of atomic-force microscopes. Those devices, which are used to examine molecules and atoms, operate at only thousands of cycles per second. "The prospects are exciting for both fundamental research and new applications," Kippenberg says.
This would more realistically be useful in developing / improving imaging sensors, than be made into highly efficient solar cells.
But, creating the laser light USED energy...
Your CD and DVD player operates by very precisely shining a laser on the DVD's tracks and detecting the reflection of laser energy from the disk. Your fiber-optic telephone/TV/Internet service needs the ability to detect laser light after it has come through a long distance of fiber optic cable. You start getting the picture? A better way to detect/capture laser energy has huge implications.
According to the paper, DARPA funded the research.
In the eighties, in the corporate research labs at the Foxboro Company, we were fabricating and optically (laser) exciting near-identical silicon microstructures. Even moreso, we were optically exciting piezoelectric quartz tuning forks -- which produced electrical power from optical energy.
It's amazing how many times the wheel is re-invented...
Based on my experience working with engineers: "It's beneath me to use some other moron's inferior wheel. Clearly, the wheel I create will be far better!"
FReepmail me if you want on or off my health and science ping list.
Thanks for the link.
Thanks neverdem. This will help in the construction of the Terminators.
Photons have no mass, yet they can make something vibrate. Huh? Vibration is movement, inducing movement requires kinetic energy, there is no kinetic energy in a collision when there is no mass.
When it’s quantum it’s guaranteed to be confusing. Throw out everything you learned in high school and undergrad physics and start anew.
Photons have no rest mass, but they have momentum and can knock particles around.
“Nano vibrator”, “Zipper Cavity”
Sometimes the jokes just write themselves.
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