Optical highway: Yale researchers generated repulsive optical forces by splitting a single beam of light so that each half traveled through a different length of waveguide. Because one half of the beam traveled farther than the other, they arrived in the center region out of phase, causing the two waveguides to repel each other. When the light beams were in phase, they attracted each other. The two triangular shapes at the bottom are the optical input and output ports.
Mo Li
The repulsive side of an optical force could lead to ultra-fast telecommunications.
Demonstrating a fundamentally new optical phenomenon, researchers at Yale University have shown the second half of an optical force that could make silicon photonics devices--such as those used in high-speed communications, network cards, even video and TV cables--faster and more capable.
Results like these showing novel ways to control light "don't come along very often," says Oskar Painter, a microphotonics researcher at Caltech who was not involved in the work. "There's a push to do more with optical components," Painter adds, and the Yale group's results are "totally new."
Scientists theorized in 2005 that tiny beams of light confined on a silicon chip could attract or repel each other when placed in close proximity, similar to the electromagnetic forces between positive and negative charges. Last year a group led by Yale University professor Hong Tang first demonstrated the "attractive" side of this optical force. Now the group has demonstrated the second side of the force, repulsion, which makes its effects reversible.
Previously, says Mo Li, the lead author of the paper published in Nature Photonics, they could "pull" with the force, but they couldn't "push." Now the researchers can do both. The accomplishment opens the possibility of using light to manipulate light in microphotonic devices, rather than using mechanical elements like microheaters or power-hungry optical crystals.
Though the force is too weak to use on larger scales--two laser pointers couldn't attract or repel each other, for example--the optical force operates strongly on the microscale, making it ideal for ultrahigh-speed, all-optical control of nanomechanical devices, according to MIT applied-mathematics professor Steven Johnson. In particular, Johnson points to the importance of being able to switch between attractive and repulsive optical forces, something that has not been experimentally demonstrated before.
Harnessing the optical force should enable faster data transfer in applications like fiber-optic telecommunications, where information can be encoded on multiple wavelengths of light and sped through a single fiber-optic cable in a process called wavelength division multiplexing. This process currently requires converting optical signals to electrical signals for modulation or amplification, and then converting them back to optical signals and sending them on their way. Using light to manipulate the optical signal could eliminate the need for electrical rest stops along the fiber-optic highway. "If you can directly transfer light to light," says Li, "it will be cheaper and faster."
Another problem with current optical multiplexing is that the devices that make the process work are relatively large--taking up prime real estate on silicon wafers--and they have to be engineered with strategically placed microheaters, which use changes in temperature to tune each wavelength of light just right. Such devices are slow and can cause cross-talk. Other light-manipulation techniques use special crystal materials that respond to high-intensity light to change the material properties of photonic devices.
A silicon nanobeam uses optical force to do mechanical work in an integrated circuit.
Virtual particles called excitons could speed data through telecom networks.
For the first time, a silicon-based optical cable will be commercially available.
Basic Research making the components
Much of the research done on Silicon optics has been monumental over the last 8 years! For example we can slow light, stop light, transmit light through silicon, amplify light through silicon, and now combined or subtract light.
These are all fundamental functions needed to make more complex silicon optical electrical devices. So for now I think they are doing smart research, clarifying the basic functions, before moving into more complex applications! My hats is off to this team for their great work!
Dr. Brian Glassman
Ph.D Innovation Management from Purdue University
amplifying light to laser quality
Nice question about amplifying light but I recall a basic laser device simply bounces light back and forth which is the same as forward and reverse light and then when the maximum yield is reached one end of the tube is opened and the light comes out as Laser Light, all starting from a basic internal light source. Course the gas is a particular influence to prevent overheating & keeps its integrity so it does not spectrum inside the tube caused by light and yet achieving Laser quality from a ordinary light source is amplifying light. Perhaps 'niravadesai' would like to build a simple laser to discover this principle.
If I could study this more rapidly I would incorporate it into the operation within the Four "Component Vehicle Manufacturing Plant(s)" (better known as 'The Fabrication Component Center') and include audio/video feeds in the light as a bonus for all of the rooms. It is a nice idea to think that magnetic resonance could generate electricity but if you think about it light can as well create electricity so why do we not consider making electric helicopters that do not need electrical cable connections to recharge since they could use a landing pads light course. Richard a old friend of mine long ago reached the point of sending audio/video through light to broadcast a TV show and then we lit a light bulb without using any power line. He had a nice experimental electronic kit and seemed more capable at accomplishing anything at all with it. I never had such when I was in Junior High School, he was a High School Grad. We together envisioned the future where electric cars were to be owned by everyone, only some construction businesses and food service businesses could afford gasoline and diesel fuels, isn't that the way we are heading today with a gasoline tax threatening to tax our transportation needs, adding a Health Care Tax would double the burden on taxpayers, any surtax on Health Care risks the essence of a free society making it a risk to endorse when aircraft crash producing lawsuits that aim at the gamblers dream come true. What would be expected, a rebate for those whom won awards from courts because they need Health Care, awards from courts could reach more than a million dollars each?
Re: amplifying light to laser quality
Dear Sir,
I was referring to semiconductor optical amplifiers which could be integrated with the semiconductor lasers on the same chip. You can find more information on them at this link:
http://en.wikipedia.org/wiki/Optical_amplifier
Where can i find details of how this force arises? With out understanding the details what i see is beams of light causing either positive or negative forces on 2 wave guides depending on phase relationship. Could the attractive and repulsive forces be viewed as microscopic curvatures in space, or is it better explained another way?
Dose this have implactions for astrophyics
Could the discovery of a new force not totaly change the shape of how things like black wholes and other objictes with supper high light denisties are thought to work.
eaven forces this small would affect things like red-shift over billions of light year distances
so what am i missing when there is no comment on such possiabilates and definatly no uproar in the physic community
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niravadesai
2 Comments
Can we not use Optical Amplifiers for the same purpose ?
Also how can changing between attractive and repulsive forces provide amplification ?
Reply