Doubling microsecond single pulses in a KTP crystal

The 90° phase-matching SHG is performed for microsecond single pulses from a Nd3+:YAP laser in a KTP crystal with the 29% conversion efficiency. The 90° phase-matching temperature is 54°C. The crystal surface damage threshold measured without and with an antireflection coating was 107±11 and 40±4 J cm-2, respectively.