Superconducting Nanowire Single Photon Sensor

The nanowires, which have a diameter of only 50 to 100 nanometers, are fabricated from thin films of tungsten silicide, a compound of tungsten and silicon. Cooled to a few degrees above absolute zero, it is superconducting. That means electrons in the wires need only absorb a tiny amount of energy from an incoming photon to generate an electrical signal.