Simulations of photon-assisted field emission: their significance in basic science and device applications

Simulations suggest that a laser may significantly increase the current in field emission through a resonant interaction in which tunneling electrons exchange quanta with the radiation field. Resonance occurs when the difference between the reduced barrier height and the electron energy is approximately 0.9 times the energy of a photon of the radiation field. Simulations suggest that it is possible to generate and detect ultrawide-band signals from DC to 100 THz by photomixing two or more lasers focused on an emitting tip. Mixer current densities of 106–108 A/m2 could be produced by focusing two lasers on a tungsten tip, where each laser has a power flux density of 1010 W/m2, and one laser is swept while the other is fixed at λ=700 nm.