Generation and field-resolved detection of ultrafast synthetic multi-THz transients

With the availability of intense and stable femtosecond sources, the modern focus of ultrafast science has been shifting toward precise coherent control of light-matter interaction on the fundamental time scales. Such control necessarily entails the ability to generate phase-stable symmetry-broken synthetic optical waveforms. The most direct approach to accomplish this is to superpose a fundamental field with its even-harmonic, while exercising control of their relative phase. To this end, it has been already demonstrated that synthetic ω-2ω pulses drastically enhance XUV and THz generation in gas plasmas, as well as allow for control of quantum interference currents in semiconductors. In this work we demonstrate generation and field-resolved detection of strongly symmetry-broken highintensity synthetic multi-THz transients for the first time.