High-extinction electron pulses by laser-triggered emission from a Schottky emitter

We study electron emission from a Schottky tip induced by nanosecond laser pulses. Prompt sub-nanosecond emission is observed at low laser power, with moderate voltage bias applied to the tip. We show that electron pulses demonstrate high extinction with electron emission after the pulse suppressed by up to 92 dB. Photoemission is shown to be highly nonlinear with laser intensity while maintaining nearly linear field emission, as probed by the laser polarization dependence. We suggest the emission is described by a photo-assisted thermally enhanced field emission process.