Study of phosphate Nd：glass slab multipass amplifier system with high beam quality

A phosphate Nd:glass Brewster angled slab oscillator and multipass amplifier system has been built up,where a novel three pass amplifier with two prisms has been proposed and a Cr4+:YAG colour center crystal has been used as the passive Q-switcher.In our experiment the output with high beam quality of Mx2=1.49 and My2=1.57 and with an energy gain of 23 has been achived.The experimental data have been compared with the numerical calculation results,showing a good consistency.