Laser-induced photoemission from tungsten and diamond tips

We present experimental results on laser-induced photoemission from nanotips made of different materials, and we compare photoemission from a metal surface (tungsten) to a dielectric (diamond). Ultrashort laser pulses (15-300 fs) are used to trigger electron emission from nanotips with radii <; 100nm under a moderate tip bias. We show how different laser parameters as the repetition rate, the mean energy or the polarization influence the photoemission. We characterize the DC field emission and the photoemission with measurements of the current but also spatial and spectral profile of the electrons.