Amplification of picosecond pulses to 100 W by an Yb:YAG thin-disk with CVBG compressor

摘要

High average power picosecond lasers have become an import tool in many fields of science and industry. We report on progress in development of 100 kHz, 100 W picosecond Yb:YAG thin disk laser amplifier with fundamental spatial mode at the HiLASE laser center. More efficient direct pumping to an upper laser level has been employed in order to suppress thermal loading of the thin disk active medium and to increase system stability. We also carefully analyzed and described all benefits of this so called zero phonon line pumping (ZPL) for fundamental spatial mode cavity design and successfully increased extraction efficiency of the amplifier to ＞ 28 %. A novel approach of high-power picosecond pulse compression using a space saving and easy-to-align chirped-volume Bragg grating (CVBG) with high dispersion and high net efficiency approaching 88 % allowed us to build a robust and highly compact pulse compressor. A 100 kHz train of sub-1-milijoule pulses compressed bellow 2 ps (FWHM) in almost diffraction limited Gaussian beam has been successfully generated from this highly compact (900 × 1200 mm) thin-disk-based Yb:YAG regenerative amplifier.