Slow down the speed of light

By using a tiny silicon device, scientists at IBM's US-based firm have been able to slow down 1/300 times the speed of ordinary light.

This device, called crystal waveguide , could in the future help create computers that use light instead of electricity to communicate. This type of computer will use only a fraction of the energy of today's computers.

Light travels at 300,000 kilometers per second, but it can be slowed down in resonance-dispersive materials. In preliminary experiments, researchers designed different machines to slow down the speed of light in the laboratory.

These experiments, cooling the light using ultra-cold atomic clouds, needed huge equipment. IBM scientists say their light-slowing devices were first made with industrial materials, and are commercially viable.

The crystal waveguide, less than half a centimeter wide, is made of silicon using conventional chip fabrication. By heating the device, scientists can control the speed of light in about 100 parts per billion .

This achievement could one day help create optical computers, said Yurii Vlasov, a physicist at IBM's Watson Research Center. In computerized systems, making slower pulses of light can carry data very quickly. The exploitation of slow light phenomena can be applied from optical data storage to optical data transfer.

Optical devices transmit data by photons, the smallest particle of light. More importantly, optical devices generate less heat, eliminating the problem of heat and power consumption of modern computers.

CONFIDENTIAL ( Xinhuanet )