A simplified approximate expression for the effective nonlinear coefficient of type-II second-harmonicgeneration in KTiOPO4 was obtained by observing that the difference between the refractive indices nx and ny is 1 order of magnitude smaller than the difference between nz and ny (or nx). The agreement of this approximate equation with the true definition is good, with a maximum discrepancy of 4%.
© 1993 Optical Society of America
K. Asaumi, "Approximate effective nonlinear coefficient of second-harmonic generation in KTiOPO4," Appl. Opt. 32, 5983-5985 (1993)