Parametric waveform synthesis: a scalable approach to generate sub-cycle optical transients

Abstract

The availability of electromagnetic pulses with controllable field waveform and extremely short duration, even below a single optical cycle, is imperative to fully harness strong-field processes and to gain insight into ultrafast light-driven mechanisms occurring in the attosecond time-domain. The recently demonstrated parametric waveform synthesis (PWS) introduces an energy-, power- and spectrum-scalable method to generate non-sinusoidal sub-cycle optical waveforms by coherently combining different phase-stable pulses attained via optical parametric amplifiers. Significant technological developments have been made to overcome the stability issues related to PWS and to obtain an effective and reliable waveform control system. Here we present the main ingredients enabling PWS technology. The design choices concerning the optical, mechanical and electronic setups are justified by analytical/numerical modeling and benchmarked by experimental observations. In its present incarnation, PWS technology enables the generation of field-controllable mJ-level few-femtosecond pulses spanning the visible to infrared range.

Spatial-to-spectral phase coupling mechanisms in bulk continuum generation

“…A significant phase shift is then undergone by the WL pulse, simply due to the variation in the filament's propagation length in the crystal. We therefore consider that, although wavefront fluctuations are not necessarily deleterious to the filamentation mechanism itself, they do have a significant impact on the spectral phase, and hence on any subsequent application requiring shot-to-shot stabilization of this phase (compression, intra-pulse DFG, CEP stabilization, waveform synthesis) [23].…”