Control of THz Radiation from Gaseous Plasmas Produced by Intense Optical Fields

Abstract

Ultrashort terahertz pulses can be produced via frequency conversion from strong femtosecond two- and multi-color pulses focused in a noble gas. The mechanism is based on the nonlinearity produced by tunnel ionization of gas atoms. In this article the new possibilities to control the characteristics of the resulting THz pulses such as wave shape, and intensity by engineering the pump waveshape are discussed. The so-called saw-tooth pump shape is demonstrated to optimize electron velocities affecting the resulting THz emission.