Simulations of high-power pulsed terahertz sources using laser-assisted field emission

We are studying ultrafast optoelectronics in a new medium the clean surface of a nanoscale tip of a polyvalent refractory metal in vacuum during field emission. Field emission of electrons responds to changes in the potential in less than 2 fs, so the speed is only limited by the means that are used to couple to these pulses in the current. Extremely high current densities occur in field emission, up to 10⁹ A/m² in steady-state, or 10¹² A/ m² with pulsed operation, so that nanoscale sources could have a high energy output. This calculation is supported by measurements of laser-assisted field emission with femtosecond lasers.