Tongpeng Zhao,Shaohua Ji,Degao Zhong,Fei Teng,Shakir Ullah,Siyuan Hu,Jie Tang,Bing Teng
The organic nonlinear optical (NLO) material N, N-dimethyl-4-[2-(2-quinolyl) vinyl] aniline (DADMQ) has been synthesized and high-quality single crystal with the dimension of 8 × 1 × 0.5 mm 3 was grown from methanol solvent by slow cooling method for the first time. Single crystal and powder XRD studies show that DADMQ crystal belongs to the orthorhombic space group Pna2 1 . All the functional groups and structure of the synthetic material can be determined from FT-IR and 1 H NMR spectral analyses. The thermal properties can be studied through TG/DTG and DSC analyses, and its melting point is confirmed at 184.9 ℃. Some critical optical characteristics like the optical transmittance, optical absorption coefficient (α), energy band gap ( E g ), cut-off wavelength (λ max ) and extinction coefficient (κ) can be carried out through UV–vis-NIR spectral analysis. The dielectric features of the title crystal have also been measured. Furthermore, there is a blue emission appeared at 493 nm through PL spectral analysis. The second harmonic generation (SHG) efficiency of the title crystal has been measured, which indicates that DADMQ has 3.64 times greater than KDP crystal.
Run Ye,Bin-Wen Liu,Xiao-Ming Jiang,Jian Lu,Hui-Yi Zeng,Guo-Cong Guo
Exploration of a new nonlinear optical (NLO)-active functional motif is important in the rational design of promising infrared (IR) NLO materials. Compared with typical tetrahedral MQ4 (M = IIB, III, IV metals; Q = S, Se) motifs, MQ3 (M = As, Sb) pyramids favor high second-harmonic generation (SHG) efficiency while frequently hindering phase matching (PM) because of excessively large optical anisotropy. The surfactant–thermal method was first adopted to achieve PM in MQ3-containing systems and synthesize mixed covalent–ionic IR NLO materials. Two new thioarsenates of AMnAs3S6 (A = Cs, Rb) exhibiting strong PM SHG efficiencies comparable to commercial AGS and laser-induced damage thresholds of one order higher than AGS were obtained. The [As3S6]3– unit in their structures is an unprecedented NLO-active functional motif, which can be useful in designing new IR NLO compounds with large SHG efficiency. In addition, the surfactant–thermal method provides a new general strategy for synthesizing new IR NLO materials.
Exploring new infrared nonlinear optical (IR NLO) materials with superior overall properties is scientifically and technically important. However, large second-order harmonic generation (SHG) efficiencies and high laser-induced damage thresholds (LIDT) are incompatible, which makes realizing this goal a challenge. The IR NLO performance of an A-NIIB-MIIIA-Q (Q: chalcogen) system was optimized by simultaneously modulating A/(M + N) and M/N ratios (A: alkali metal; N, M: tetra-coordinated metals), and SHG–LIDT balance was achieved. Three new sulfides, KCd3Ga5S11 (1), RbCd4Ga3S9 (2), and Cs2Cd2Ga8S15 (3), containing the same CdS4 and GaS4 but with different A/(Ga + Cd) and Ga/Cd ratios were obtained. Among these compounds, compound 3 exhibits both the largest SHG efficiency (0.5 × AgGaS2) and LIDT (35 × AgGaS2), which can be ascribed to the Ga/Cd modulation for enhancing the NLO functional motif distortions and SHG efficiency as well as the A/(Ga + Cd) modulation for enlarging the band gap and LIDT. Remarkably, compound 3 is the first phase-matchable IR NLO material in the A-NIIB-MIIIA-Q family. This article proposes a novel avenue to explore infrared nonlinear materials with superior comprehensive properties by modulating the A/(M + N) and M/N ratios.