Researchers Create Optical Wires That Cancel And Repel Each Other In One Crystal

University of Arkansas researcher Scot Hawkins will present the group's findings on Friday at the Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science meeting in Baltimore this week.

Currently computers run on electric circuits and wires. These wires carry a limited amount of information, take up lots of space, and produce electric fields that interfere with one another, said University of Arkansas professor Greg Salamo.

Optical wires have no interfering fields and can carry more information using less space than electronic wires. This makes them desirable for computers, telephones and other electronic devices, Salamo said.

Optical "wires" actually contain no material -- they are created by light beams shone into a crystal in an electric field. Instead of spreading out like typical light beams, the light is trapped in a line, creating a "wire" which can be used to transmit information.

However, little is known about the interactions of these optical wires -- and whether interference between two such wires in a crystal will cause undesirable "cross talk."

The work presented at the meeting focuses on what happens when two narrow beams of light are projected into an indium phosphide crystal in an electric field.

When the light waves were in phase with each other, they merged in the crystal to form one beam, the researchers report.

When the light beams have opposite phases -- when their peaks and troughs come at the same time -- the wires repel each other.

"You can use this to your advantage," Hawkins said.

In current fiber optics networks, a circuit must be disconnected and reconnected to make a switch, or have a permanent splice -- where half the signal goes down each fiber.

With an optical wire, the "wire" is built by shining a light beam through a small crystal in an electric field. It can be targeted to different places in fractions of a second by changing the direction of the light beam.

This means the optical wires are faster and more efficient than even their fiber optic counterparts. "We can make optical wire where we want it, when we want it," Hawkins said.

If such wire were used to transfer calls on a telephone, for instance, the callers would not even notice the switch, Hawkins said.