Electro-optical systems got a boost recently by researchers who claims that a new kind of transistor--an excitonic transistor--can accept optical inputs and provide optical outputs, but which operates on the photonic data as if it were electrical--yielding the best of both worlds. Look for excitonic transistors to begin appearing commercially within 10 years. R.C.J.
Excitonic transistors could solve the persistent problem of electronically switching optical communications signals, but until now have required very expensive supercooling. Now, researchers have refined the materials mix and architecture of excitonic transistors to permit economical operation at 125 degrees Kelvin, which they say is attainable with inexpensive liquid nitrogen. Unlike conventional electronic circuits, exitonic transitors automatically convert optical signals into excitons--bound electron-hole pairs. After processing the excitons with conventional signal processing techniques, the electron-hole pairs are recombined, thereby emitting an photon at the output of the circuit.