One-stage hollow-core fiber-based compression of Yb:KGW lasers to the single-cycle regime

The generation of intense, waveform-controlled, single-cycle pulses based on Yb:KGW amplifiers is central to integrating these lasers with attosecond metrology and spectroscopy. Here, we demonstrate single-stage, multi-octave (∼ 2.4 octaves) spectral broadening of Yb:KGW amplified pulses in a neon-pressurized hollow-core fiber (HCF) capillary and their compression to the single-cycle regime (1.1 cycles at 880 nm) using chirped mirrors. Utilizing homochromatic attosecond streaking (HAS), we characterize the field waveforms of the generated pulses and demonstrate precise control of their carrier-envelope phase (CEP). Our results provide a simplified route to single-cycle pulse generation using Yb:KGW technology, previously possible only with Ti:sapphire-based front ends. This work paves the way for advanced applications in attosecond science, strong-field physics, and spectroscopy.