2 µm femtosecond fiber laser at low repetition rate and high pulse energy.

In the paper, a 2 µm high energy fs fiber laser is presented based on Tm doped fiber at a low repetition rate. The seed laser was designed to generate pulse train at 2 µm at a pulse repetition rate of 2.5 MHz. The low repetition rate seed oscillator eliminated extra devices such as AO pulse picker. Two-stage fiber amplifier was used to boost pulse energy to 0.65 µJ with chirped pulse amplification.