Optical Waveform Synthesis and Its Applications

The quest for ever-shorter optical pulses has been ongoing for over half a century. Although few-cycle pulses have been generated for nearly 40 years, pulse lengths below the single-cycle limit have remained an elusive goal for a long time. For this purpose, optical waveform synthesizers, generating high-energy, high-average-power pulses via coherent combination of multiple pulses covering different spectral regions, have been recently developed. They allow unprecedented control over the generated optical waveforms, spanning an extremely broad spectral range from ultraviolet to infrared. Such control allows for steering strong-field interactions with increased degrees of freedom. When driving high-harmonic generation, tailored waveforms can produce bright attosecond pulse trains and even isolated attosecond pulses with tunable spectra up to the soft X-ray range. In this paper recent progress on parametric and hollow-core fiber waveform synthesizers is discussed. Newly developed seeding schemes; absolute, relative, and spectral phase measurement; and control techniques suitable for synthesizers are described. The progress on serial and parallel waveform synthesis based on Ti:sapphire and Ytterbium laser systems and their latest applications in high-harmonic generation in gaseous and solid media, attosecond science, and laser wakefield acceleration is discussed.