Artist’s conception of a computer chip made of light
 
In quantum mechanics, photons cannot interact with each other in free space. Light waves have only freely passed through each other without changing their state or path, until now.

Vienna University of Technology researchers have discovered a method to force photons to interact with each other using ultra thin glass fiber and a resonator. The photon is introduced into the resonator and directed in a circle, not unlike the motion of pendulum, and interacts with the glass fiber. The movement causes a 180 degree inversion in the photon. Light is blocked from entering the resonator which prevents the photon from oscillating back to it’s original state.

In preventing light from entering the resonator, a maximum entangled state of photons can be created which is necessary for feats such as quantum teleportation, or transistors made of light, which can be used for quantum computing. 
Greg Giles