CC BY
43HiLASE-O-3
100 W industrial thin disk regenerative amplifier
H. Zhou1, M. Chyla1, J. Horacek1, P. Crha1, J. Muzik1, O. Novak1, M. Smrz1, T. Mocek1 1HiLASE Centre, Institute of Physics of the Czech Academy of Sciences, Dolni Brezany, Czech Republic
High-power ultrafast laser with high repetition rate has been applied in various scientific and industrial fields, such as laser shock peening (LSP), laser micromachining, Mid-IR generation and laser welding. we report on an industrial grade picosecond Yb:YAG thin-disk regenerative amplifier of TRL 6 level for wavelength conversion, Mid-IR generation and various industrial applications. It is a new generation of several years operated Perla C100 laser developed at HiLASE Centre. The laser provides a stable output at repetition rate of 50 kHz with average power of 100 W and <2 ps pulse duration. The thermal effect of the thindisk is one of the main issues affecting the system stability. In order to reduce the quantum defect in the gain medium, the Zero Phono Line (ZPL) pumping approach was applied. By directly pumping the disk at 969 nm wavelength to the upper level of Yb:YAG, a highly stable fundamental mode operation was achieved. The front-end was based on PM fiber components in order to obtain stable and reliable seed source. Three stages of amplification, including two stages of amplification with single cladding gain fiber and one stage of amplification with double cladding gain fiber, are designed to stretch and amplify the seed pulses from 150 fs, 50 MHz and ~200 mW with 10 nm spectral bandwidth to 500 ps, 1 MHz and 1 W with 3 nm spectral bandwidth. The front-end can be upgraded by a 4-pass rod amplifier in order to obtain higher seed power. The seed beam from the fiber amplifier can be amplified up to 9W output power after passing the rod-type gain media (2%-doped Yb:YAG) 4 times. The 4-pass scheme of the rod amplifier can provide high stability, high amplification efficiency and good beam quality of M2<1.17. The average power stability of 0.7% of regenerative amplifier is supported by stable operation of the front-end with relatively high seed energy. A Chirped Volume Bragg Grating (CVBG) is used as a robust and compact pulse compressor for high power picosecond pulses. Benefiting from the high dispersion, 2 mJ at 50 kHz laser pulses are compressed bellow 2 ps. Cavity stabilization, beam pointing stabilization systems and pulse picker are integrated into the control system of the laser which together with a robust, thermally stabilized housing provides the stability necessary for realization of the various industrial goals. The pulse-on-demand capability of the laser allows the user to control each individual pulse. Benefiting from the modular design concept, this laser can be used for wavelength conversion and Mid-IR generation modules also developed at HiLASE Centre.
