Scientists have developed single-photon switching transistors

Transistors act as tiny electronic or current switches in computers, and scientists are developing chip components that can use optical switches. A team led by MIT researchers last week reported that they created a transistor with a single photon switch. MIT's Wenlan Chen and colleagues' phototransistors utilize a cryogenic neon atomized cloud suspended between mirrors. By default, the “on” state allows a beam of light to pass through the neon atom cloud undisturbed (left). With the effect of electromagnetic induction transparency, a photon can be used as a "door" to turn the switch off.

The injected photon can excite the neon atoms so that they reflect light beams that attempt to cross the atomic cloud (right). A photon can block about 400 photons. Other physicists called this study a major breakthrough. Although they must be practical, they must also address the issue of laser energy consumption.