New method of unipolar THz pulse generation in photo-ionised xenon plasma
A. V. Bogatskaya, E. A. Volkova, A. M. Popov
Abstract
Abstract We propose a new method for producing terahertz (THz) pulses with a high degree of unipolarity. This idea is based on the nonuniform amplification of seed THz one-cycle carrier envelope phase pulses in nonequilibrium xenon plasma. The significant impact of the propagated pulse on the evolution of plasma leads to a strong decrease in the gain coefficient within the duration of the one-cycle pulse. As a result, the leading edge of the pulse is amplified while the trailing tail of opposite polarity is absorbed; this effect leads to the formation of unipolarity. These results are obtained by the self-consistent solution of the second-order wave equation and kinetic Boltzmann equation for the electron velocity distribution function relaxation.