Table-top sources of ultrashort THz pulses

In this paper techniques for the generation and measurement of ultrashort pulses in the frequency range from about 0.1 to 10 THz are reviewed. The methods for generation are restricted to table-top systems based on short-pulse lasers in the visible or in the near-infrared. Three techniques are dealt with in detail: photoconductive switches, difference frequency generation and plasma sources. Definitions and methods to measure the pulse width are given, among them cross-correlation and measurements of the electric field of these pulses as a function of time by photoconductive switches and electro-optic sampling.