Warping yields better light chip

Light can transmit information and it can sense chemicals and microbes. The critical device for controlling light for these uses is the resonator, which briefly stores light of a specific frequency, or color.

California Institute of Technology researchers have made an optical resonator on a chip that is nearly 10,000 times more efficient than previous designs.

The researchers formed the resonator -- a 160-micron silicon disk on a pedestal -- using standard chip-making techniques. They smoothed the disk, and shrank and warped it with an infrared laser beam. A micron is one-thousandth of a millimeter.

Light resonates in the device by circling around the outside edge of the disk. The smooth surface and warped shape allows light to circle longer than in previous chip-based resonators. The device is also better at preserving the light's frequency.

The more efficient resonator could be used to filter light in telecommunications networks, extend the frequency range of chip-based lasers, make more sensitive biological and chemical sensors and build chip-based quantum computing and communications devices.

The resonator is ready for practical use, according to the researchers. The work appeared in the February 27, 2003 issue of Nature. -TECHNOLOGY RESEARCH NEWS