High-average power pulsed Yb:YAG thin-disk laser

We developed the elemental technologies to construct a 1-kW, 10-kHz thin-disk laser. We obtained the wellpolarized CW output of over 900 W without any compensation optics of the birefringence error. The extinction ratio of output was over 1:140. We developed and installed the water-cooled Pockels cell into the CW laser cavity to act as a polarization rotator by applying a DC-voltage to the cell. We confirmed that the cooled cell did not create distinguished birefringence and thermal lensing over 900-W operation. The deforming of thin-disk at high power operation was estimated by using a commercial M2 meter. We optimized the cavity configuration from the estimation results to obtain high beam quality. After the optimization, the M2 values kept up to 3.5 until the output reached to 400 W. At the 500-W output, the M2 in vertical and horizontal plane were 3.65 and 3.02, respectively.