Abstract

For type II phase-matched frequency doubling in a biaxial crystal, we proved that the amplitude ratio of two vertical fundamental wavefields in the crystal is an important factor affecting the frequency doubling efficiency (FDE). The plot of FDE as a function of the ratio has been drawn by numerically solving the coupling wave equations. The optimum orientation of the frequency-doubling crystal to the laser rod has been determined in which the FDE is the highest. When KT/OPO₄(KTP) crystal is used as the frequency doubler in a YAG laser, the optimum orientation is the position in which the ratio is 0.976.

© 1987 Optical Society of America