摘要
High-order harmonic generation(HHG)in noble gases driven by femtosecond lasers is currently a feasible solution to obtain ultrafast pulses in the extreme ultraviolet(EUV)wavelength range.Implementation of high-flux EUV sources requires driving HHG using an ultrafast laser source in the visible wavelength range with MHz repetition rate.In this paper,we employ a multi-pass cell followed by chirped mirrors to compress 1-MHz,200-W,300-fs pulses at 1.03μm to a duration of 35 fs.The resulting 186-W compressed pulses are focused onto 0.5-mm thick beta barium borate crystal to drive second-harmonic generation and produce positively chirped pulses at 520 nm.These green pulses are de-chirped to 26 fs in duration with an average power of 64 W,which,to the best of our knowledge,represents the highest average power of green pulses with a duration below 100 fs.
基金
supported by the Key Deployment Special Research Project of the Chinese Academy of Sciences(Grant No.PTYQ2022YZ0001)
the National Natural Science Foundation of China(Grant Nos.62175255 and 62227822)。
