200  kHz 55  W Yb^3+: YVO_4-based chirped-pulse regenerative amplifier

A chirped-pulse regenerative amplifier based on a Yb:YVO4 (Yb:YVO) crystal was demonstrated for the first time, to our knowledge. A novel wavelength-independent off-axis technique was used to deliver 26.6 W of pump power with a low quantum defect. It was seeded by means of a 120 fs Yb:YVO4 oscillator. It generates as much as 5.5 W of average output power with chirped pulses and 4.2 W with 200 fs compressed pulses at a 200 kHz repetition rate. A maximum pulse energy of 140 μJ was obtained at pulse repetition frequencies up to 25 kHz at the central wavelength of 1018 nm.