Production of very high electron density assisted by lasers

We analyze a new basic concept for very high electron density emission from metal photocathodes conjugating the action of two lasers. The action of the first laser -a low frequency (IR or FIR) and high intensity source (> 10-100 MW/cm2)- is supposed to lower the potential barrier and enhance energy of conduction electrons at the surface of material and then increase significantly the effective photoelectric quantum yield. The second laser is a visible or UV laser with a lower intensity (< 100 kW/cm2), extracting an high electron density by direct photoelectric effect