Linear intensity dependence of photo-induced field emission from tungsten

As a first step in an investigation of the polarization dependence of photo-induced field emission from tungsten, the dependence of the photocurrent on the intensity of illumination has been studied. The beam from a CW krypton ion laser operating at selected wavelengths in the visible region of the spectrum was focussed onto the field emitter, and the emission current in a narrow energy range (chosen to minimize tip heating effects) was …