RT Journal Article T1 Boosting terahertz generation in laser-field ionized gases using a sawtooth wave shape A1 González de Alaiza, Pedro A1 Babushkin, Ihar A1 Bergé, Luc A1 Skupin, Stephan A1 Cabrera Granado, Eduardo A1 Köhler, Christian A1 Mörgner, Uwe A1 Husakou, Anton V. A1 Herrmann, Jens AB Broadband ultrashort terahertz (THz) pulses can be produced using plasma generation in a noble gas ionized by femtosecond two-color pulses. Here we demonstrate that, by using multiple-frequency laser pulses, one can obtain a waveform which optimizes the free electron trajectories in such a way that they acquire the largest drift velocity. This allows us to increase the THz conversion efficiency to 2%, an unprecedented performance for THz generation in gases. In addition to the analytical study of THz generation using a local current model, we perform comprehensive 3D simulations accounting for propagation effects which confirm this prediction. Our results show that THz conversion via tunnel ionization can be greatly improved with well-designed multicolor pulses. PB American Physical Society SN 0031-9007 YR 2015 FD 2015-05-06 LK https://hdl.handle.net/20.500.14352/23092 UL https://hdl.handle.net/20.500.14352/23092 LA eng NO © 2015 American Physical Society NO DFG DS Docta Complutense RD 9 abr 2025