Passive Q-Switching

DRDO has developed passively Q-switched continuously pumped Nd:YVO4 generating ~16 ns wide pulses at ~70 kHz repetition rate by end pumping an Nd:YVO4 crystal of 1 mm thickness and 3 mm x 3 mm cross-section employing a CW laser diode with maximum output power of 700 mW at 808 nm.

A Cr:YAG crystal with 90 per cent initial transmission and an output coupler of 300 mm radius of curvature (ROC) and 98 per cent reflectivity at 1064 nm was used for the purpose.

Experiments are in progress to generate second harmonic and to further reduce the pulse widths that will lead to several scientific and defence applications.