A multi-pumped configuration with conjugated dual parabolic mirrors for thin disk laser

The thin disk-shaped active medium is a very thin laser crystal with one face mounted on a heat sink. The large cooled-surface-to-active-volume ratio avoids thermal problems occurring in conventional high power rod or slab lasers and enables high power TEM00 operation. However, the absorption of pump light in the thin disk crystal for single pass is very small in the end-pumped configuration. A classical multi-pumped configuration with a parabolic mirror and a pair of folding prisms given by Geisen is more suitable to realize at least 24 pumping passes in the thin disk crystal by using iterative relay imaging method. With the excellent pumping technology, CW laser output power of 10kW in multi-mode operation, 4kW in fundamental-mode operation and 8kW with a beam quality of 3 mmmrad are achieved from a single Yb:YAG disk crystal.