Towards CEP-stable single-cycle pulses with microjoule-level energy at 8 MHz repetition rate

Low-noise trains of few-fs pulses are widely used for studying and controlling ultrafast dynamics in matter. Microjoule-level pulse energies are often more than sufficient to trigger and observe these dynamics, and repetition rates in the few MHz range allow reduced acquisition times and improved signal-to-noise ratios—crucial for studies of processes with low-interaction cross-sections. The latest generation of fibre lasers can provide ultrashort pulses with stable carrier-envelope phase (CEP) at unprecedented energies and hundreds of kHz repetition rates [1] , [2] . However, because the generated pulses are hundreds of fs long, multiple compression stages are required to reach the few fs regime, thus increasing the system complexity and reducing the throughput efficiency.