 This paper proposes a method to measure the cubic non-linearity parameter. Mathxmlns equals display equals inline e-beta 2 of polycrystalline metals using second harmonic generation. The method involves calibrating the receiver, correcting for diffraction and attenuation, and then correcting for source non-linearity. When this is done, the cubic non-linearity parameter can be accurately measured even with thinner samples and lower input voltages. This article was authored by Haianjo Zhang, Haio Zhang Xin, Xu Zeng Zhang, and others.