Figure 1.

(a) Scanning electron microscope image of a single-gate field emitter array with molybdenum nanotips, 5 µm-pitch, with the tip apex radius of curvature of ~10 nm. (b) Schematic setup of the experiment. The emitters under dc bias potential of Vge are irradiated by near infrared laser pulses. The dc current and the laser-induced electron pulses are collected by a Faraday cup. (c) The relation between the laser-induced electron bunch charge and the excitation near infrared laser peak intensity. The laser pulses are 50 fs-long repeated at 2 kHz and focused on the 2 mm-diameter FEA with the incident angle of 60°. (d) Schematic diagram of the electron emission process subsequent to the excitation of the electron by a near infrared photon.