Coupling of optical parametric processes in an optical superlattice through quadratic nonlinearity was analyzed theoretically. Solving the coupled equations, we found that efficient quasi-phase-matched third-harmonic (TH) generation depends not only on the magnitude of the coupling coefficients but also on their ratio. Theoretically, all the fundamental energy can be transferred to the TH at a particular ratio. In other cases, there exists an optimum condition that corresponds to a maximum TH conversion efficiency. The result is of practical importance for the design of TH devices.
© 2000 Optical Society of America
Chao Zhang, Yong-yuan Zhu, Su-xia Yang, Yi-qiang Qin, Shi-ning Zhu, Yan-bin Chen, Hui Liu, and Nai-ben Ming, "Crucial effects of coupling coefficients on quasi-phase-matched harmonic generation in an optical superlattice," Opt. Lett. 25, 436-438 (2000)