Thermal effects in the DKDP Pockels cells in the 215-300  K temperature range

The thermal and electro-optical effects in Pockels cells with deuterated potassium dihydrogen phosphate (DKDP) crystals in the 215-300 K temperature range were investigated. Half-wave voltage decreases linearly with cooling, thereby it reduces seven times (up to 1 kW) with cooling to 215 K. The optical power of the thermally induced lens falls twice on cooling to 215 K from 300 K; thermally induced depolarization is almost independent of temperature and determined by input radiation power. A significant reduction of the thermally induced depolarization in a DKDP crystal with the axis inclined to the polarization plane of the beam was demonstrated numerically and experimentally. Thus, the DKDP crystals cooled to 215 K allow the creation of a low-voltage Pockels cell working with a high average and peak laser power.