High-energy femtosecond laser system based on a fiber laser seeder, Yb:YAG single crystal fiber and chirped volume Bragg grating

A high-energy chirped pulse amplification system based on a Yb doped fiber seeder, two-stage single crystal fiber (SCF) amplifier with a simple single-pass structure is demonstrated in this work. An amplified power of 52.2 W with a beam quality of less than 1.3 at 200 kHz is obtained, to our best knowledge, this is the highest power obtained with a single-pass amplification structure of the SCF with the energy of hundreds of microjoules. An excellent power stability of 0.32% is obtained. Dispersion between the chirped fiber Bragg grating (CFBG) stretcher and the chirped volume Bragg grating compressor is matched via the use of a self-made temperature tuning device of CFBG. As a result, a pulse duration of 740 fs and a compressed power of 31.4 W are obtained at a repetition rate of 200 kHz. In order to assess the influence of pulse duration induced by the nonlinearity during the amplification and increase the output pulse energy,the repetition rate of the self-made fiber seeder is changed to 100 kHz. A compressed power of 28.4 W and a pulse width of 858 fs are obtained, corresponding to a pulse energy of 284 µJ and a peak power of 331 MW. This compact and high-energy femtosecond laser system will find various applications in both scientific research and industrial implementation. (letter)