29 August 2007—Scientists say one way to build a really fast computer is to use light rather than electricity to perform calculations. Now researchers from Mikhail Lukin’s group at Harvard and the Danish National Research Foundation Center for Quantum Optics and the Niels Bohr Institute at the University of Copenhagen have taken a big step toward this goal with the first feasible plan for making a transistor that uses photons of light instead of electricity. Details were recently published online by the journal Nature Physics .

Unlike other schemes, this new optical transistor could be controlled with just one photon, making it very efficient. And it would work for a broad range of frequencies of light, instead of just one (as with some previous proposals), making it easy to use.

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The Ultimate Transistor Timeline

The transistor’s amazing evolution from point contacts to quantum tunnels

1 min read
A chart showing the timeline of when a transistor was invented and when it was commercialized.

Even as the initial sales receipts for the first transistors to hit the market were being tallied up in 1948, the next generation of transistors had already been invented (see “The First Transistor and How it Worked.”) Since then, engineers have reinvented the transistor over and over again, raiding condensed-matter physics for anything that might offer even the possibility of turning a small signal into a larger one.

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