Single photon transistor

Control an optical “signal” propagating across some channel via a “control” at a gate. The optical signal for this may be as simple as a stream of photons, perhaps at some frequency, and in general the control is also some number of photons. Unfortunately, unlike electrons, photons have very weak non-linear interactions with one another. The concept shown here is only one such method of creating a strong non-linear interaction between photons. The hopeful solution proposed here is to utilize a tight concentration of optical fields in conjunction with guided surface plasmons along a conducting nanowire in order to achieve strong non-linear interactions between optical emitters. Two photons are sent through a nanowire towards an atom, where they collide, such that one photon (red) transfers its information to the other photon. Today the signal is an electrical current. For a quantum computer the signal can be an optical one, and it works using a single photon which is the smallest component of light. To work, the photons have to meet and “talk”, and the photons very rarely interact together” says Anders SØndberg SØrensen who is a Quantum Physicist at the Niels Bohr Institute at Copenhagen University. He explains that light does not function like in Star Wars, where the people fight with light sabres and can cross swords with the light. That is pure fiction and can´t happen. When two rays of light meet and cross, the two lights go right through each other. That is called linear optics. What he wants to do with the light is non-linear optics. That means that the photons in the light collide with each other and can affect each other. This is very difficult to do in practice. Photons are so small that one could never hit one with the other. Unless one can control them -and it is this Anders SØrensen has developed a theory about.