Hongyuan Sha,Dongling Yang,Yanran Shang,Zujian Wang,Rongbing Su,Chao He,Xiaoming Yang,Xifa Long
Sulfates are always promising short-wave ultraviolet (UV) nonlinear optical (NLO) candidates, if their birefringence could be greatly improved. Here, in terms of the insufficient birefringence , the unity of heteroleptic tetrahedral groups and triangular ones was proposed and implemented. Thus, a new semi-organic crystal, [C(NH 2 ) 3 ]S 3 O 6 (G 2 S 3 O 6 ), was obtained, which is composed of [S 3 O 6 ] 2− and [C(NH 2 ) 3 ] + groups. It exhibits excellent optical properties with a short absorption cutoff edge of 218 nm, a strong NLO response of 1.4 × KH 2 PO 4 , and more especially, a large birefringence of 0.097@546 nm. This birefringence leap makes the G 2 S 3 O 6 crystal achieve a phase-matching behavior under a 532 nm laser. Thus, the synergy of [S 3 O 6 ] 2− and [C(NH 2 ) 3 ] + groups results in excellent optical performances. This finding opens a new horizon for exploring novel UV NLO crystals.
Wen Xin,Lin Chensheng,Luo Min,Fan Huixin,Chen Kaichuang,Ye Ning
[PO 4 ] 3− possesses small microscopic second-order susceptibility and polarizability anisotropy, which inherently result in weak second-harmonic generation (SHG) and small birefringence. Herein, a new noncentrosymmetric phosphate, [C(NH 2 ) 3 ] 3 PO 4 ·2H 2 O, was successfully designed and synthesized by a solution evaporation method. [C(NH 2 ) 3 ] 3 PO 4 ·2H 2 O without metal ions is composed of planar conjugated guanidine cations and PO 4 tetrahedrons, which are connected by hydrogen bonds, forming a three-dimensional network. Physical property measurements indicate that the title compound displays an SHG response of 1.5 × KH 2 PO 4 (KDP) and a larger birefringence (0.055@546.1 nm) compared with most reported ultraviolet nonlinear optical phosphates. Furthermore, first-principles calculations reveal that the π-conjugated planar [C(NH 2 ) 3 ] + cations and [PO 4 ] 3− groups are responsible for its excellent linear and NLO properties.
危险品化学品经营许可证（带存储）