Pb9Si8O22Cl6 and Pb3.07Ca1.93Si3O11: Two Ultraviolet Nonlinear Optical Materials Exhibit a Moderate Second Harmonic Generation Response

Finding novel efficient nonlinear optical materials with large second-order nonlinearity for the UV spectral range remains a formidable challenge, especially for silicate systems. Using a high-temperature solid reaction in a tight vacuum environment, two ultraviolet nonlinear optical materials with a moderate second harmonic generation (SHG) response have been created: Pb₉Si₈O₂₂C_l6 and Pb_3.07Ca_1.93Si₃O₁₁. The SHG values they computed are roughly 2.4 and 3.5 times higher than those of KH₂PO₄ (KDP). This study reports on Pb₉Si₈O₂₂C_l6 and Pb_3.07Ca_1.93Si₃O₁₁ syntheses, crystal structures, and optical characteristics. In addition, the relationship between electronic structure and optical properties was clarified by first-principles theoretical computations.