CEP-stable Tunable THz-Emission Originating from Laser-Waveform-Controlled Sub-Cycle Plasma-Electron Bursts
Abstract
We study THz-emission from a plasma driven by an incommensurate-frequency two-colour laser field. A semi-classical transient electron current model is derived from a fully quantum-mechanical description of the emission process in terms of sub-cycle field-ionization followed by continuum-continuum electron transitions. For the experiment, a CEP-locked laser and a near-degenerate optical parametric amplifier are used to produce two-colour pulses that consist of the fundamental and its near-half frequency. By choosing two incommensurate frequencies, the frequency of the CEP-stable THz-emission can be continuously tuned into the mid-IR range. This measured frequency dependence of the THz-emission is found to be consistent with the semi-classical transient electron current model, similar to the Brunel mechanism of harmonic generation.
Keywords
Cite
@article{arxiv.1501.00658,
title = {CEP-stable Tunable THz-Emission Originating from Laser-Waveform-Controlled Sub-Cycle Plasma-Electron Bursts},
author = {T. Balčiūnas and D. Lorenc and M. Ivanov and O. Smirnova and A. M. Zheltikov and D. Dietze and J. Darmo and K. Unterrainer and T. Rathje and G. Paulus and A. Baltuška and S. Haessler},
journal= {arXiv preprint arXiv:1501.00658},
year = {2015}
}