Photoelectric Emission from Thin Film Optically Enhanced Nano-Forest Cathodes

Optically enhanced nano-forest cathodes are electron sources developed for high power devices. The principle of cathode operation is based on coherent light coupling photon energy into resonant, nanometer sized antennae, which can theoretically generate large current densities with little energy applied. Pulsed laser energy, resonantly tuned, can be coupled into pins on the order of the wavelength in length, thereby heating the tips of the pins, resulting in thermionic or thermofield emission. Initial experiments have been conducted to determine optically enhanced electron emission characteristics of several representative cathodes. This paper presents measured electron emission from nano-forest materials and compares them to theoretical estimates of electron emission.