We have observed electron emission by laser irradiation of tungsten needle cathodes at surface electric fields of the order of 109 to 1010 V/m using cw and pulsed lasers at wavelengths near 530 nm. This is below the threshold for ordinary photoemission. The photoelectric field emission displays a nonlinear dependence on the intensity of the laser; measurements with a 7-ns pulsed laser show no discernible relaxation time in the emission. The maximum current obtained from 1-micron needle tips is of the order of 0.1 mA. The laser intensity is restricted by damage caused by thermal effects at the high repetition rate (several kHz) of the Nd:vanadate laser. A low repetition rate laser is now being installed, and the measurements will be extended to shorter laser wavelengths, near 350 and 260 nm.
