Abstract
Highly charged states created through multiple ionization of gases are shown to enhance terahertz (THz) generation by intense, single- or two-color femtosecond laser pulses. A one-dimensional, nonpropagating fluid model reveals the main conversion processes up to laser intensities, namely, ionization-induced photocurrents and plasma current oscillations. For increasing intensities, we demonstrate a cyclic growth in the THz signal associated with the different binding energies of argon and helium. This behavior is confirmed by direct particle-in-cell and unidirectional pulse propagation simulations. Changes in the forward and backward THz spectra owing to multiple ionization are discussed.
- Received 11 December 2014
- Corrected 27 August 2015
DOI:https://doi.org/10.1103/PhysRevA.91.041801
©2015 American Physical Society
Corrections
27 August 2015