24 mJ sub-nanosecond kilohertz 515 nm laser achieved by the KTP crystal

In response to the demand for high-energy, high-repetition-rate sub-nanosecond green lasers in industrial and other fields, as well as the currently problems with relatively single implementation solutions and high crystal costs, it has been proposed that the KTP crystal was used as frequency doubling crystal and the 1030 nm disk regenerative amplifier as the fundamental frequency laser for the high-energy 515 nm sub-nanosecond laser. The maximum output energy is 24.17 mJ with a repetition rate of 1 kHz. The pulse width measured by the oscilloscope is less then 719 ps. The variation trend of the frequency doubling power, efficiency and the crystal temperature with the injection power for the crystal lengths of 2.5 mm and 5 mm has been done in experiment. According to the results of frequency doubling efficiency and temperature changes with different lengths crystals, the increased temperature in crystal leading to the phase mismatch is the main reason for frequency doubling efficiency decreased. The longer the crystal, the faster the temperature rises, and the more sever impacts on the frequency doubling efficiency. Therefore, in order to further improve the frequency doubling efficiency of high-energy sub-nanosecond kilohertz green laser based on KTP crystals, it is necessary to consider the influence of temperature on phase matching in advance and optimize the crystal cutting angle based on actual temperature.