Using a tiny silicon device, scientists with IBM successfully slowed down light to 1/300th of its ordinary speed.
This device, called crystal waveguide, may help develop future computers using light instead of electricity for communications, reported scientists in Thursday issue of the journal Nature. These computers will use only a fraction of the energy of current machines.
Light moves at 300,000 km per second, but it can be slowed down in dispersive materials near resonances. In earlier experiments, scientists designed different machines to decelerate the light in laboratories.
These experiments, "cooling" the light using clouds of ultra cold atoms, needs huge equipments. IBM scientists said that their light-slowing device is the first to be manufactured with industrial material, and has the potential of being commercialized.
The so-called crystal waveguide, less than half-thousandth of a centimeter across, was made of silicon using conventional chip-manufacturing processes, according to the researchers.
Heating the photonic crystal waveguide with a 2-milliwatt integrated micro-heater, scientists could also control the velocity of light efficiently in about 100 nanoseconds. A nanosecond is one billionth second.The light can be further slowed by applying an electric field to the waveguide, the Nature paper said.
This achievement may one day help realize the envision of optical computer, said Yurii Vlasov, physicist at IBM's Watson Research Center and first author of the Nature paper.
In a computer system, orderly moving slower light pulses could carry data rapidly. Exploitation of slow light phenomena has potential for applications ranging from all-optical storage to all-optical switching, he explained.
Optical equipment transmits data on photons, the smallest measure of light. More important, optical equipment generates less heat, curbing the growing problem of heat and power consumption in modern computers.
But recent optical components are huge, expensive, and can't be manufactured in the millions like silicon chips. Creating optical components has been more of an art than a science.
"Moreover, the implementation of external lasers, low pressures and low temperatures prevents miniaturization and hinders practical applications," the Nature paper said.
Using the technology of crystal waveguide, the idea to scale down the size of the optical components can open the way to significantly reduce the cost of optical components, IBM scientists noted.
Although they called this progress an "experimentally demonstrate" in the paper, their goal was eventually to use it in products.
The ability to tune the speed of light was important for future optical devices. Making the devices out of tiny silicon, allowing the optics and the electronics to be arranged on the same silicon chip, will make them more practical, the scientists said.