Synergism of multiple functional chromophores significantly enhancing the birefringence in layered non-centrosymmetric chalcohalides

Large birefringence is important and indispensable for laser technology to meet the application demands. However, it is still a challenge to obtain optical materials with large birefringence that can extend the commercial birefringent crystals. Herein, we present a birefringence screening and analysis system to explore high-performance optical materials by introducing multiple functional chromophores. Using the high-throughput screening methodology, optical materials with one or two functional chromophores were explored. In particular, the chalcohalides Hg3AsQ4X (Q = S or Se; X = Cl, Br, or I) with multiple functional chromophores were screened out using the density functional theory and high-throughput screening method. The results show that Hg3AsQ4X (Q = S or Se; X = Cl, Br, or I) have an extremely large birefringence (Δn: 0.391–0.493 at 1064 nm), two times that of the commercial birefringent crystal CaCO3 (0.172 at 1064 nm). And novel birefringent material motifs activated by the synergism of the d10 cation Hg2+, the layer of lone pair electrons of As3+ cation, and the mixed anions Q2−/X− (Q = S or Se; X = Cl, Br, or I) were found.