Relativistic-intensity 1.3 optical cycle laser pulses at 1kHz from a stretched hollow-core-fiber compressor

Waveform-controlled few-cycle light pulses have become an important tool in contemporary ultrafast science not only because they provide high temporal resolution but also because they facilitate sub-cycle gating of highly nonlinear process [1]. Sub-cycle gating of relativistic laser-plasma interactions is of particular interest as it could be a potentially efficient source of high-energy attosecond XUV pulses [2] or MeV femtosecond electron bunches [3] for time-resolved applications. Achieving this requires near-single-cycle pulses with TW peak power and high spatiotemporal fidelity, so they can be focused down to relativistic intensity (>10 18 W/cm 2 for 800nm light).