AN OPTICAL transistor that switches a laser beam on and off, rather than an electric current, could form the building block of future light-based computers.
Vahid Sandoghdar and colleagues at the Swiss Federal Institute of Technology in Zurich suspended a hydrocarbon dye molecule in a crystalline matrix cooled by liquid helium. They then aimed a weak orange laser beam at the molecule, which soaks up most of its energy.
When they zapped the hydrocarbon molecule with a weak green beam it re-radiated orange light (Nature, DOI: 10.1038/nature08134). “That light then constructively interferes with the orange beam and makes it brighter, effectively amplifying it,” says researcher…
