INTRACAVITY 2ND-HARMONIC GENERATION OF 0.532-MU-M IN BULK PERIODICALLY POLED LITHIUM-NIOBATE

We report on CW quasi-phase-matched intracavity frequency doubling of a 1.064 mu m Nd:YAG laser. The 5 mm long and 0.2 mm thick crystal of periodically poled LiNbO3 was Brewster angle cut. When located intracavity, it presented an effective nonlinear coefficient d(33) of 4.5 pm/V and an estimated loss per pass less than 10%. The observed temperature bandwidth of similar to 5 K compares favourably with the theoretical value and indicates that the whole length of the crystal was contributing to the frequency doubling process.