 The researchers have developed new caucogenide materials that can be used for non-linear optical effects such as second harmonic generation. These materials contain lead cations in their cationic groups, which allow them to contribute to the non-linear optical effects. The materials have been shown to have large phase matching SHG intensities, exceeding those of Agis II, and have bandgap values greater than 2.33 EV, allowing them to avoid two-photon absorption at 1,064 nanometers. Additionally, they have lower anisotropies of thermal expansion coefficients, resulting in higher damage thresholds. This article was authored by Wenfei Chen, Binwen Lu, Xiaomin Pei, and others.