Nanotip response to monocycle terahertz pulses

The interaction of monocycle terahertz (THz) fields with metal nanostructures such as nanotips is attracting a lot of interest for the development of new applications such as THz-scanning tunneling microscopy and ultra-fast field emission. New methods have been introduced to measure the enhanced THz near field waveform in the vicinity of a nanotip surface. Here, we present results obtained by electron field emission in the multiphoton emission regime. The nanotip mimics the behavior of an antenna with a simplified equivalent circuit. We show that the electrical characteristics can be calculated using the nanowire geometry approximation and taking into account a conduction shell with a thickness smaller than the material skin depth. The results introduce a method to predict the antenna response of the nanotip and thus the near THz field waveform.