β-BaB2O4 (BBO) crystals over 2 cm in length in the direction suitable for optical parametric oscillation (OPO) pumped by the third and fourth harmonics of Nd:YAG laser output have been grown in our laboratory. With the third harmonic pump, continuous tuning from 450 nm to 1.88 µm using a single set of mirrors has been achieved. With multiple sets of mirrors, tuning from ~400 nm to 2.5 µm can be achieved. With 266-nm pump and multiple sets of mirrors, continuous tuning from 330 nm to 1.37 µm has been observed. The tuning range below 400 nm is particularly important because there are few other convenient tunable sources. These BBO optical parametric oscillators are high power, solid state sources with efficiencies currently in the 10-20% range and potentially up to 50-60%. All these are made possible due to recent advances in the growth technology of BBO crystal and improved design features of OPO. The growth, characterization, and OPO applications of BBO crystals are discussed.
© 1989 Optical Society of AmericaPDF Article