Generation of few-nanosecond pulses from a KTP electro-optically Q-switched Tm:YAP laser at 2 μm.

We report the demonstration of a 2 μm electro-optical Q-switched Tm:YAP laser using a hydrothermally grown KTP Pockels cell, which generates a record-short pulse duration of 2∼3 ns at high pulse repetition frequencies ranging from 70 kHz to 120 kHz. The pulse duration is independent of incident pump power due to the balance of the inversion ratio and cavity losses at the duty cycle of 98%. Maximum average output power of 7.3 W is obtained at 70 kHz, corresponding to peak power of 45 kW. The shortest pulse duration of 2.12 ns is obtained at 80 kHz. To our knowledge, the obtained pulse duration is the shortest achieved for a Q-switched 2 μm Tm laser. The results make the KTP Pockels cell attractive for the achievement of high PRFs and short pulses at a 2 μm laser.