Development of Optical Parametric Oscillator Tunable in the Range 970-1460 nm

Optical parametric oscillator (OPO) tunable in the range 970-1460 nm has been developed using bet barium borate (BBO) crystal as the gain medium and second harmonic of Nd:YAG laser as pump source. Two sets of resonators were used to cover the range; first was nearly degenerate (970-1180 nm) and the second was nondegenerate (1240-1460 nm). The measured threshold pump pulse energy was nearly 8 mJ. Maximum signal pulse energy of about 14 mJ was obtained for pump pulse energy of nearly 31 mJ. Power scaling efficiency was about 70 per cent. The signal pulse width was ~5 ns corresponding to the pump pulse width of ~ 9 ns. OPO signal beam quality was Gaussian although the pump beam was top-hat multimode.