Infrared (IR) nonlinear optical (NLO) materials are the key devices for generating tunable infrared output between ~ 3 and ~ 20 μm by laser frequency conversion techniques. Based on the...

Large band gap and strong nonlinear optical (NLO) effect are two valuable but contradictory parameters,whichare difficult to balance in one infrared (IR) NLO material. Herein, the first alkali and alkaline-earth metal diamond-like (DL) IR NLO material Li 4 MgGe 2 S 7 ,p resenting ah oneycomb-like 3D framework constructed by 6-membered LiS 4 rings and GeMgS 6 zigzag chains,w as rationally designed and synthesized. The introduction of rigid alkali metal and alkaline-earth metal LiS 4 and MgS 4 tetrahedra effectively broadens the band gap of DL compound to 4.12 eV (the largest one in the reported quaternary metal chalcogenides), generating ah igh laser damage threshold of 7 AgGaS 2 at 1064 nm. Furthermore,L i 4 MgGe 2 S 7 displays as uitable SHG response (0.7 AgGaS 2 )w ith at ype Ip hase-matching behavior.T he results indicate that Li 4 MgGe 2 S 7 is apromising IR NLO material for the high-power laser application and it provides an insight into the design of new DL compound with outstanding IR NLO performances.

Design and exploratory synthesis of new mid-infrared (mid-IR) nonlinear optical (NLO) materials are urgently needed for modern laser science and technology because the widely used IR NLO crystals still suffer from their inextricable drawbacks. Herein, a multi-level data-driven approach to realize fast and efficient structure prediction for the exploration of promising mid-IR NLO materials is proposed. Techniques based on machine learning, crystal structure prediction, high-throughput calculation and screening, database building, and experimental verification are tightly combined for creating pathways from chemical compositions, crystal structures to rational synthesis. Through this data-driven approach, not only are all known structures successfully predicted but also five thermodynamically stable and 50 metastable new selenides in A I B III Se 2 systems (A I = Li, Na, K, Rb, and Cs; B III = Al and Ga) are found, among which eight outstanding compounds with wide bandgaps (> 2.70 eV) and large SHG responses (>10 pm V −1 ) are suggested. Moreover, the predicted compounds I42d-LiGaSe 2 and I4/mcm-KAlSe 2 are successfully obtained experimentally. In particular, LiGaSe 2 exhibits a robust SHG response (≈2 × AGS) and long IR absorption edge that can cover two atmospheric windows (3-5, 8-12 µm). Simultaneously, this new research paradigm is also applicative for discovering new materials in other fields.

Large band gap and strong nonlinear optical (NLO) effect are two valuable but contradictory parameters,whichare difficult to balance in one infrared (IR) NLO material. Herein, the first alkali and alkaline-earth metal diamond-like (DL) IR NLO material Li 4 MgGe 2 S 7 ,p resenting ah oneycomb-like 3D framework constructed by 6-membered LiS 4 rings and GeMgS 6 zigzag chains,w as rationally designed and synthesized. The introduction of rigid alkali metal and alkaline-earth metal LiS 4 and MgS 4 tetrahedra effectively broadens the band gap of DL compound to 4.12 eV (the largest one in the reported quaternary metal chalcogenides), generating ah igh laser damage threshold of 7 AgGaS 2 at 1064 nm. Furthermore,L i 4 MgGe 2 S 7 displays as uitable SHG response (0.7 AgGaS 2 )w ith at ype Ip hase-matching behavior.T he results indicate that Li 4 MgGe 2 S 7 is apromising IR NLO material for the high-power laser application and it provides an insight into the design of new DL compound with outstanding IR NLO performances.

The interrelation of arrangement modes of isolated SbQ3 ligands on structures and birefringences has been systematically studied in series of chalcogenides.

The exploration of novel infrared nonlinear optical (IR NLO) materials with large second-harmonic generation (SHG) responses and wide band gaps has become very imperative recently. Herein we reported two noncentrosymmetric compounds, LiBa4Ga5Q12 (Q = S, Se), crystallizing in space group P 21 c (No. 114), which feature 3D frameworks built by a basic [Ga5Q16]17– windmill cluster and LiQ4 tetrahedra in a cesium chloride topological structure. Both compounds satisfy the desired balance between good SHG responses (∼1.5× that of AgGaS2) and wide band gaps (3.43 and 2.44 eV) with remarkable laser damage thresholds (21× and 6× that of AgGaS2). The theoretical calculations uncover that the [Ga5Q16]17– cluster makes major contributions to the SHG effect in LiBa4Ga5Q12. In addition, the structure–performance relationship among all compounds in the I–II4–III5–VI12 system has been discussed systematically, which indicates that the introduction of the alkali metal lithium in the I site is beneficial for the production of large band gaps. This work will be helpful in exploring novel IR NLO materials with special structures and comprehensive properties in the chalcogenide system.

Combining alkali ……a nd alkaline-earth metal units with an excellent diamond-like structure (DLS) template,the first alkali and alkaline-earth metal DLS infrared nonlinear optical (NLO) material Li 4 MgGe 2 S 7 was rationally designed and fabricated. This work enriches the diversity of DLS compounds,and opens an avenue for the design and exploration of new infrared NLO materials with excellent NLO properties,a so utlined by Shilie Pan, Junjie Li et al. in their Research Article on page 24333.

Crystals with both large birefringence and wide transparent range possess broad application in the areas of optical communications, laser industry and modulation of the light polarization requirement. In this work,...