Output characteristics of a gadolinium scandium gallium garnet laser operating in the pulse-periodic regime

A pulse-periodic neodymium laser was made from a new crystal, which was gadolinium scandium gallium garnet activated with chromium and neodymium ions (GSGG:Cr³⁺: Nd³⁺). When the pump energy was 7.3 J per pulse, the output energy in the free-running regime was 255 mJ, i.e., the absolute efficiency was 3.5%. At the maximum pulse repetition frequency (20 Hz), which was limited by the nature of the power supply unit, the average output power was 5 W when the pump power was 145 W. The differential efficiency was 4.5%, which was 2.4 times higher than for an YAG:Nd³⁺ crystal operated under similar conditions. The diameter of the GSGG active element was 5 mm and its length was 50 mm. The differential efficiency in the Q-switched regime was 3% when the pump energy was in the range 3–7 J.