Coupled-wave equations that are suitable for focused Gaussian beams in an optical superlattice are derived. Solving the coupled equations, we find the optimum condition for efficient third-harmonic generation (THG), in which a negative phase mismatch is needed because of the Gouy effect. The conversion efficiency can be kept at a high level over a wide range of the ratio of the two coupling coefficients. The result is of practical importance for the design of THG devices.
© 2003 Optical Society of America
(190.0190) Nonlinear optics : Nonlinear optics
Guo-Ding Xu, Tie-Wei Ren, Yue-Hua Wang, Yong-Yuan Zhu, Shi-Ning Zhu, and Nai-Ben Ming, "Third-harmonic generation by use of focused Gaussian beams in an optical superlattice," J. Opt. Soc. Am. B 20, 360-365 (2003)