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.

References in corpus (4)

• Determination of the Carrier-Envelope Phase of Few-Cycle Laser Pulses with Terahertz-Emission Spectroscopy
• Field-driven femtosecond magnetization dynamics induced by ultrastrong coupling to THz transients
• Tailoring THz radiation by controlling tunnel photoionization events in gases
• Spectral self-action of THz emission from ionizing two-color laser pulses in gases

Cited by in corpus (5)

• Terahertz and higher-order Brunel harmonics: from tunnel to multiphoton ionization regime in tailored fields
• Laser-induced plasma generation of terahertz radiation using three incommensurate wavelengths
• Revealing plasma oscillation in THz spectrum from laser plasma of molecular jet
• Terahertz generation in dual-color laser: continuum electron in strong-field single-atom ionization
• High order Brunel harmonics and supercontinuum formed by a weak optical pump in presence of a strong terahertz field