Laser Light Switch Could Leave Transistors in the Shade

Researchers from the Swiss Federal Institute of Technology have developed an optical transistor that uses one laser beam to control another, potentially forming the foundation for a new generation of ultrafast light-based computers. The researchers say laser-based transistors can be used to create light-based computers, which would use optical fibers to carry light.

To create an optical transistor, the researchers suspended tetradecane, a hydrocarbon dye, in an organic liquid, which was then frozen using liquid helium to create a crystalline matrix in which individual dye molecules could be targeted using lasers. When a finely tuned orange laser beam is targeted on a dye molecule, most of the laser is absorbed, creating a much weaker output beam. However, when the molecule also is targeted with a green beam, the molecule starts producing a strong orange light of its own that boosts the power of the orange output beam. Switching the orange beam from weak to strong is similar to how a transistor's control electrode switches a current between on and off. The ability to make this switch using a single molecule could enable billions of optical transistors to be built on photonic chips.

From New Scientist
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