Picosecond Diode Pumped Nd:YAG Laser for Initiation of Localized Energetic Processes in Non-laboratory Applications

A picosecond diode pumped Nd:YAG laser with active mode-locking is presented for the problems of initiating and studying the dynamics of localized energy processes, such as explosive detonation, electric discharge, optical breakdown, evaporation of metal films with plasma formation. The laser master oscillator is made according to a simple linear two-mirror cavity scheme 600 mm long. The use of negative feedback allows one to generate a single spectrally limited pulse closed in the cavity with high quality spatial and temporal profiles. The pulse width from 150 to 600 ps can be set by a simple change in power on the acousto-optical modulator. The giant train after Q-switch cavity dumping contains 7–10 (half-maximum envelope) pulses with a peak energy of about 1 mJ. Pulse isolator allows to select 1, 2 or 3 pulses from the train with a contrast at least 100. Diode pumped single-pass amplification cascade less than 200 mm in length makes it possible to obtain energy of 100 mJ. The laser design is adapted for carrying, rapid deployment and measurements in the temperature range from +10 to +30°C outside the optical laboratory. The predictability of the pulse generation time is about 100 ps. The factors affecting the shift and the jitter relative to the reference crystal oscillator phase are considered.