Large Second Harmonic Generation Response Research Articles

Alignment of Λ-Shaped Basic Building Units to Construct One New KMoO3(IO3) Polar Polymorph.

Nonlinear optical (NLO) crystals assume an irreplaceable role in the development of laser science and technologies, yet the reasonable design of a high-performance NLO crystal remains difficult owing to the unpredictability of inorganic structures. In this research, we report the fourth polymorph of KMoO3(IO3), i.e., δ-KMoO3(IO3), to understand the effect of different packing patterns of basic building units on structures and properties. Among four polymorphs of KMoO3(IO3), the different stacking patterns of Λ-shaped cis-MoO4(IO3)2 units result in α- and β-KMoO3(IO3) featuring nonpolar layered structures, whereas γ- and δ-KMoO3(IO3) display polar frameworks. Theoretical calculations and structure analysis reveal that IO3 units can be regarded as the main source of its polarization in δ-KMoO3(IO3). Further property measurements show that δ-KMoO3(IO3) exhibits a large second-harmonic generation response (6.6 × KDP), a wide band gap (3.34 eV), and a broad mid-infrared transparency region (∼10 μm), which demonstrates that adjusting the arrangement of the Λ-shaped basic building units is an effective approach for rationally designing NLO crystals.

Nonlinear optical responses in nodal line semimetals

Nonlinear optical responses, such as shift current and second-harmonic generation (SHG), of topological semimetals have been subjects of great interest because the momentum-space topological structures near Weyl or Dirac points lead to unusually large responses. This is especially important for technological applications as the shift current and SHG are often used for solar cell and frequency-changing applications for lasers, respectively. We demonstrate that nodal line semimetals can offer even larger responses at low frequencies. For example, we show that a large SHG response arises at finite doping when an external dc electric field is applied to break the inversion symmetry of an otherwise inversion-symmetric model of a nodal line semimetal. Furthermore, we introduce a model with intrinsically broken inversion symmetry, where both the shift current and SHG are singular in a range of parameters.

Two Acentric Aluminoborates Incorporated d10 Cations: Syntheses, Structures, and Nonlinear Optical Properties.

Two acentric aluminoborates (ABOs), [Zn(en)2Al{B5O9(OH)}{BO(OH)2}] (1) and [Cd(en)2AlB5O10]·H2O (2) (en = ethylenediamine), have been solvothermally made. 1 includes a two-dimensional (2D) wavy ABO layer using B5O9(OH) clusters and AlO3{BO(OH)2} groups, in which both units can be regarded as three-connected nodes, and simplifying the ABO layer to a hcb-type network. 2 features an acentric three-dimensional (3D) porous framework with a unique unc-type network constituted by strictly alternating connected B5O10 clusters and AlO4 units. The structural transformation from a 2D layer 1 to a 3D framework 2 was achieved with the elimination of the terminal hydroxyls in layer 1 by adjusting synthetic conditions in the same solvent system. Metal-amine complexes Zn(en)2/Cd(en)2 bond to the inorganic walls and are located in the cavity of frameworks 1 and 2, respectively. Compounds 1 and 2 exhibit large second-harmonic generation (SHG) responses that are 2.2 and 2.7 times those of KH2PO4 (KDP), respectively, which are among the largest powder SHG responses for all deep-ultraviolet (deep-UV) ABOs. The UV-vis diffuse reflectance spectra of 1 and 2 show a wide transparency window below 190 nm. Density functional theory (DFT) calculations indicate that the B-O units and the introduced distorted d10 metal polyhedra played a decisive role in the optical properties of both compounds.

Two pairs of chiral YbIII enantiomers presenting distinct NIR luminescence and circularly polarized luminescence performances with giant differences in second-harmonic generation responses.

By introducing enantiomerically pure mono-bidentate N-donor ligands (LR/LS) into Yb(btfa)3(H2O)2 and Yb(dbm)3(H2O), respectively, two pairs of chiral YbIII enantiomers, namely Yb(btfa)3LR/Yb(btfa)3LS (D-1/L-1) and [Yb(dbm)3LR]·[Yb(dbm)3(C2H5OH)]/[Yb(dbm)3LS]·[Yb(dbm)3(C2H5OH)] (D-2/L-2) were isolated, where btfa- = 3-benzoyl-1,1,1-trifluoroacetonate, dbm- = dibenzoylmethanate, and LR/LS = (-)/(+)-4,5-pinenepyridyl-2-pyrazine. D-1/L-1 possess mononuclear structures in which the YbIII ions are eight-coordinated, while D-2/L-2 show cocrystal structures containing Yb(dbm)3(LR/LS) and Yb(dbm)3(C2H5OH) moieties in which the two YbIII ions are eight and seven-coordinated, respectively. They not only feature different molecular structures but also present distinct linear and nonlinear optical performances. Chiral mononuclear D-1 has better near infrared photo-luminescence (NIR-PL) and circularly polarized luminescence (CPL) performances than chiral cocrystal D-2. More remarkably, D-1/L-1 show large second-harmonic generation (SHG) responses (up to 1.25/1.28 × KDP) 18/16 times those of D-2/L-2 (0.07/0.08 × KDP). In addition, D-2/L-2 represent the first examples of lanthanide cocrystal complexes with NIR-PL, NIR-CPL and SHG properties.

The Antiperovskite-Type Oxychalcogenides Ae3 Q[GeOQ3 ] (Ae = Ba, Sr; Q = S, Se) with Large Second Harmonic Generation Responses and Wide Band Gaps.

Oxychalcogenides capable of exhibiting excellent balance among large second-harmonic generation (SHG) response, wide band gap (Eg ), and suitable birefringence (Δn) are ideal materials class for infrared nonlinear optical (IR NLO) crystals. However, rationally designing a new high-performance oxychalcogenide IR NLO crystal still faces a huge challenge because it requires the optimal orientations of the heteroanionic groups in oxychalcogenide. Herein, a series of antiperovskite-type oxychalcogenides, Ae3 Q[GeOQ3 ] (Ae = Ba, Sr; Q = S, Se), which were synthesized by employing the antiperovskite-type Ba3 S[GeS4 ] as the structure template. Their structures feature novel three-dimensinoal frameworks constructed by distorted [QAe6 ] octahedra, which are further filled by [GeOQ3 ] tetrahedra to form antiperovskite-type structures. Based on the unique antiperovskite-type structures, the favorable alignment of the polarizable [GeOQ3 ] tetrahedra and distorted [QAe6 ] octahedra have been achieved. These contribute the ideal combination of large SHG response (0.7-1.5 times that of AgGaS2 ), wide Eg (3.52-4.10eV), and appropriate Δn (0.017-0.035) in Ae3 Q[GeOQ3 ]. Theoretical calculations and crystal structure analyses revealed that the strong SHG and wide Eg could be attributed to the polarizable [GeOQ3 ] tetrahedra and distorted [QAe6 ] octahedra. This research provides a new exemplification for the design of high-performance IR NLO materials.

AIB3IIC3IIIQ8VI: A New Family for the Design of Infrared Nonlinear Optical Materials by Coupling Octahedra and Tetrahedra Units.

Large second-harmonic generation (SHG) response and broad band gap are two important and competitive parameters. It is difficult to balance them out in one material. In this work, by coupling alkali earth metal (AEM) octahedra with large highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap and nonlinear optical (NLO)-active tetrahedra units, nine noncentrosymmetric (NCS) compounds, belonging to a new quaternary chalcogenide family AIB3IIC3IIIQ8VI with unique windmill-like [Mg3M3IIIQ24] (MIII = Al, Ga; Q = S, Se) units constructed by alternated [MgQ6] octahedra and [MIIIQ4] tetrahedra, are rationally designed and fabricated. The compounds show a stable structural framework but adjustable optical properties. Among them, NaMg3Ga3Se8 shows a large SHG response (∼1 × AgGaS2 (AGS)), wide band gap (in selenide) (2.77 eV), high laser-induced damage threshold (LIDT) (∼2.3 × AGS), and suitable birefringence (0.079@546 nm). It should be a potential candidate for infrared (IR) nonlinear optical (NLO) materials. The results enrich the chemical diversity of chalcogenides and open an avenue for the development of new IR NLO materials through the octahedra and tetrahedra coupled strategy.

Exploring Short-Wavelength Phase-Matching Nonlinear Optical Crystals by Employing KBe2BO3F2 as the Template.

Exploration of nonlinear optical (NLO) crystals that are competent in generating short-wavelength ultraviolet (UV, λ ≤ 266 nm, and even deep-UV, λ ≤ 200 nm) coherent light output by direct second harmonic generation (SHG) remains a formidable challenge. Herein, four UV/deep-UV NLO crystals, M2B4SO10 (M = K, Rb, and Cs) and Rb3B11PO19F3, were successfully synthesized by evolving the KBe2BO3F2 (KBBF) structure into mixed-anionic borosulfate and fluoroborophosphate systems. They display functional [B4SO10]∞ or [B11PO19F3]∞ KBBF-type layers that are composed of [BO3], [BO4], and [SO4] groups or [BO3], [BO4], [BO3F], and [PO4] groups, respectively. Experimental characterization and numerical computation results indicate that these crystals possess exceptional NLO performance, including large SHG responses (0.9-1.7 × KDP at 1064 nm and 0.1-0.3 × β-BBO at 532 nm) and adequate birefringence to fulfill the SHG phase-matching (PM) condition at 266 nm. In particular, the shortest type-I PM wavelength (λPM) of Rb3B11PO19F3 reaches 180 nm, which implies that Rb3B11PO19F3 can become a prospective deep-UV NLO crystal. In addition, single crystals of K2B4SO10, Rb2B4SO10, and Cs2B4SO10 are easily obtained by the high-temperature solution approach. This work will facilitate the discovery of short-wavelength PM NLO crystals by using the KBBF structure as the template.

Ag[SC(NH2)2]2F: A Laser Damage-Tolerant Infrared Nonlinear Optical Material

Mild hydrothermal reactions of π-conjugated SC(NH2)2, Ag(NO3), and NaF afforded a new prospective infrared (IR) nonlinear optical (NLO) crystal, namely, Ag[SC(NH2)2]2F. It shows a 3D open framework consisting of corner-sharing AgS4 tetrahedra with six-member ring tunnels that are filled by organic groups of the SC(NH2)2 molecules. Ag[SC(NH2)2]2F maintains 80% transmittance in the spectral region of 0.32–5.91 μm and features large second harmonic generation (SHG) responses with phase-matching at both 1064 nm (15.8 × KH2PO4) and 2.05 μm (0.7 × AgGaS2). It also exhibits a large band gap of 4.19 eV, resulting in a high laser-induced damage threshold (LIDT) of 9.3 times that of AgGaS2. Theoretical calculation revealed that SC(NH2)2, AgS4 tetrahedra, and F– anions all give the positive contribution to SHG effects. Ag[SC(NH2)2]2F overcomes the small band gap and low LIDT of tetrahedral-based chalcogenides while maintaining a large SHG response. This work gives a promising facile design strategy for IR NLO materials.

Isoreticular Design of KTiOPO4-Like Deep-Ultraviolet Transparent Materials Exhibiting Strong Second-Harmonic Generation.

Second-harmonic generation (SHG) is of great technological importance for applications in nonlinear optics, but it remains challenging to engineer large SHG responses in the short-wavelength ultraviolet (UV) region owing to competing microstructure requirements. Herein, we report the first examples of d0 transition-metal-based (TM-based) deep-UV-transparent nonlinear optical (NLO) crystals MOF4H2 (M = Zr (ZOF), Hf (HOF)), which exhibit unprecedented short UV absorption edges (below 190 nm). Evolving from the KTiOPO4 (KTP) structure by an isoreticular node substitution strategy, the three-dimensional frameworks of ZOF and HOF consist of corner-sharing [MO2F6] moieties that are new functional units in deep-UV NLO material design, conferring wide UV transparency and strong phase-matchable SHG response (2.2 × KH2PO4 (ZOF) and 1.8 × KH2PO4 (HOF) at 1064 nm). Such d0-TM-based [MO2F6] polyhedra preclude deleterious d-d electronic transitions, resulting in significantly blue-shifted UV absorption edges of ZOF and HOF (<190 nm). The d0-TM-based [MO2F6] polyhedra introduced in this work offer a new perspective in the construction of deep-UV transparent NLO materials, demonstrating the feasibility of an isoreticular design strategy in developing functional NLO materials.

Syntheses, structures, and optical properties of n = 3 layered Dion–Jacobson perovskites, RbEu2-xBixTi2NbO10 (0 ≤ x ≤ 2)

A series of n = 3 Dion–Jacobson type perovskites, RbEu2-xBixTi2NbO10 (0 ≤ x ≤ 2) have been synthesized by high temperature solid-state reactions. The Rietveld refinements using powder X-ray diffraction data indicate that the reported materials crystallizing in the noncentrosymmetric (NCS) polar orthorhombic space group, Ima2 (No. 46) or centrosymmetric (CS) tetragonal space group, P4/mmm (No. 123) reveal solid-solution behaviors depending on the amount of Eu3+ and Bi3+ cations. Detailed structural analyses indicate that once more than 30% of A-site cations are occupied by Eu3+ cations in RbEu2-xBixTi2NbO10, the centricity of the solid solutions changes from NCS to CS. Powder second-harmonic generation (SHG) measurements suggest while RbBi2Ti2NbO10 reveals strong SHG (2.5 × KDP), the SHG intensity abruptly decreases as small amount of Eu3+ cations occupy the site of lone pair cation, Bi3+. The origin of the large SHG response of polar RbBi2Ti2NbO10 and the abrupt decrease of SHG for the Eu3+-doped RbEu2-xBixTi2NbO10 solid solutions are explained by a detailed structural analysis and dipole moment calculations along with the electron localization function diagrams. Detailed characterizations including infrared and ultraviolet–visible spectroscopy, thermogravimetric analysis, density functional theory calculations, energy dispersive X-ray analysis, and photoluminescence measurements are provided.

三元AGa5S8 (A = K, Rb, Cs): 通过“一替多取代”策略制备的红外非线性光学材料

Commercially available infrared (IR) nonlinear optical (NLO) materials, such as diamond-like AgGaQ2 (Q = S, Se), display large NLO coefficients but relatively low laser-induced damage thresholds (LIDTs), which seriously hinder their widespread laser applications. Herein, the “one-for-multiple substitution” strategy, namely, [SZn46+ + 5Zn2+ ⇒ A+ + 5Ga3+] (A = K, Rb and Cs), is applied on the diamond-like zinc-blende ZnS, and affords three new polar ternary crystals AGa5S8 (A = K, Rb and Cs) through the solid-state method. These compounds inherit the diamond-like anionic backbone framework in ZnS where the NLO functional motifs GaS4 are arranged in a parallel manner. This characteristic accounts for the remarkable phase-matchable second-harmonic generation intensities (1.1–1.2 × AgGaS2). In addition, the inclusion of the highly electropositive A+ cations affords a band gap ranging from 3.10 to 3.37 eV, which facilitates the improvement of LIDT (9.3–12.4 × AgGaS2). To the best our knowledge, crystals AGa5S8 (A = K, Rb and Cs) are the first series of ternary A-inclusion chalcogenides with large second-harmonic generation responses (≥1.0 × AgGaS2) and wide band gaps (≥3.0 eV), fulfilling the rigorous requirements of outstanding IR NLO materials. In addition, the “one-for-multiple substitution” strategy presents the great significance of diamondlike structure evolution and provides a remarkable opportunity to achieve NLO materials.

Pb5(GeO4)(Ge2O7) and Pb3.32Ca1.68(GeO4)(Ge2O7): Two Nonlinear Optical Germanates Induced by Diverse PbOx Polyhedra.

Oxide nonlinear optical (NLO) crystals have drawn wide interest for their comprehensive physical performances including wide infrared (IR) transparency ranges, large band gaps, and good stability in open air. Here, two isostructural germanate oxides, Pb5(GeO4)(Ge2O7) (1) and Pb3.32Ca1.68(GeO4)(Ge2O7) (2), adopting the noncentrosymmetric (NCS) space group P6̅, were composed via a conventional solid-state reaction. The latter was designed by the partial cation substitution strategy based on parent 1. The whole structures of 1 and 2 are composed of isolated distorted GeO4 tetrahedra, Ge2O7 dimers, and diverse M (M = Pb, Ca, or Pb/Ca)-centered polyhedra. They exhibit second-harmonic generation (SHG) responses around 3.3 and 1.4 times that of KH2PO4 (KDP) under 1.064 μm laser radiation, respectively. Theoretical calculation results reveal that the Pb2+ cations with stereo-active long pair (SCALP) electrons of 1 favor the large SHG response, while Pb-based polyhedra showing inert SCALP electrons make predominant contributions to the moderate SHG effect of 2.

(NH4)3B11PO19F3: a deep-UV nonlinear optical crystal with unique [B5PO10F]∞ layers.

Deep-ultraviolet (DUV) nonlinear optical (NLO) crystals that can extend the output range of coherent light below 200 nm are pivotal materials for solid-state lasers. To date, KBe2BO3F2 (KBBF) is the only usable crystal that can generate DUV coherent light by direct second harmonic generation (SHG), but the layered growth habit and toxic ingredients limit its application. Herein, we report a new fluoroborophosphate, (NH4)3B11PO19F3 (ABPF), containing four different functional units: [BO3], [BO4], [BO3F] and [PO4]. ABPF exhibits a KBBF-like structure while eliminating the limitations of KBBF crystal. The unique [B5PO10F]∞ layers enhance ABPF’s performance; for example, it has a large SHG response (1.2 × KDP) and a sufficient birefringence (0.088 at 1064 nm) that enables the shortest phase-matching wavelength to reach the DUV region. Meanwhile, the introduction of strong B-O-P covalent bonds decreases the layered growth habit. These findings will enrich the structural chemistry of fluoroborophosphate and contribute to the discovery of more excellent DUV NLO crystals.

Inside Cover: Ultrawide Bandgap and Outstanding Second‐Harmonic Generation Response by a Fluorine‐Enrichment Strategy at a Transition‐Metal Oxyfluoride Nonlinear Optical Material (Angew. Chem. Int. Ed. 26/2022)

Oxyfluorides are widely studied functional solids that show great potential as nonlinear optical materials, while only few examples with a wide bandgap exist. In their Communication (e202203104), Chao Wu, Chi Zhang, and co-workers report the synthesis of a fluorine-rich oxyfluoride K5(NbOF4)(NbF7)2 by a fluorine-enrichment strategy. The crystalline oxyfluoride exhibits a wide bandgap and large second-harmonic generation response. The key role of the fluorine content in affecting the optical activity is disclosed.

Prediction of Large Second Harmonic Generation in the Metal-Oxide/Organic Hybrid Compound CuMoO3(p2c)

Noncentrosymmetric hybrid framework (HF) materials are an important system in discovering new practical second-order nonlinear optical materials. We calculated the second harmonic generation (SHG) response of a noncentrosymmetric (NCS) organic–inorganic HF compound, CuMoO3(p2c) (p2c = pyrazine-2-carboxylate) to find that it exhibits the largest SHG response among all known NCS HF materials with one-dimensional helical chains. Further atom response theory analysis revealed that the metal atoms Cu and Mo contribute much more strongly than do nonmetal atoms in determining the strength of the SHG response, which is a novel example in nonlinear optical materials known to date.

Pb4SeBr6: A Congruently Melting Mid‐Infrared Nonlinear Optical Material with Excellent Comprehensive Performance

AbstractDeveloping mid‐infrared (MIR) nonlinear optical (NLO) crystals is of current research interest, but their rational design is still faced by a great challenge because of the inherent conflict between large second harmonic generation (SHG) response and wide bandgap. To reconcile these conflicting properties, the best way is to combine multiple anions together. Up to now, various MIR NLO crystals with multiple anions are reported, such as oxychalcogenides, oxyhalides, and salt‐inclusion chalcogenide‐halides. However remarkably, the nonsalt‐inclusion chalcohalides with chalcogenide Q2– (Q = S, Se) and halide X– (X = F, Cl, Br) anions combined with the same central cations are still rarely reported. Herein, a lead chalcohalide Pb4SeBr6 is reported, which belongs to the nonsalt‐inclusion chalcohalide and is synthesized by the rational aliovalent substitution of Se2– for Br– anions with PbBr2 as the template. Importantly, this compound can exhibit excellent NLO properties, including large SHG response (1.3 × AgGaS2 (AGS)), wide IR transparent region (0.5–25 µm), and high laser damage thresholds (10 × AGS) as well as the congruently melting performance. These indicate that Pb4SeBr6 is a promising MIR NLO crystal and it will also provide some insights for exploring new MIR NLO crystals based on the rational partial anion substitution.

Design of a diamond-like infrared nonlinear optical material LiBS2 with ultra-wide band gap

The exploration of new infrared (IR) nonlinear optical (NLO) materials with large second-harmonic generation (SHG) responses and wide band gap (Eg) is an urgent need but challenging. Starting from the superior unit combination strategy and considering the advantages of borates, chalcogenides and Li elements, we have focused our attention on the exploration of IR NLO materials in the Li-based thioborates. Four novel non-centrosymmetric LiBS2 structures, were obtained successfully through crystal structure prediction by analogy and structural optimization based on the thermodynamic and dynamic stability analysis. Among them, LiBS2-I exhibits an ultra-wide band gap Eg = 4.4 eV, moderate SHG response 0.6 × AgGaS2, and suitable birefringence Δn = 0.04 at 1064 nm, which satisfies the good balance between Eg ≥ 3.0 eV and dij ≥ 0.5 × AgGaS2. The role of microscopic units [BS4] in NLO effect was investigated. This work enriches the structural diversity of thioborates and provides a new approach to the exploration of excellent IR NLO materials.

Achieving Short‐Wavelength Phase‐Matching Second Harmonic Generation in Boron‐Rich Borosulfate with Planar [BO3] Units

AbstractUltraviolet (UV) nonlinear optical (NLO) crystals which can produce short‐wavelength lasers via a direct second harmonic generation (SHG) process are of great importance in modern laser technology. Currently, the exploration of UV NLO crystals in borosulfates is nearly stagnant since the non‐phase matching (PM) property lies on the small birefringence induced by the intrinsically small optical anisotropy of the tetrahedral groups. Herein, for the first time, the planar [BO3] units were introduced into borosulfates leading to a boron‐rich borosulfate (NH4)2B4SO10 with unprecedented [B4SO10]∞ layers and evidently enhanced birefringence. To the best of our knowledge, it achieves the shortest SHG PM wavelength of 252 nm in all reported borosulfates with deep UV cutoff edge (184 nm), large SHG response (1.1×KDP at 1064 nm and 0.15×β‐BBO at 532 nm) and large birefringence (0.053 at 1064 nm) and is easy to grow single crystals via simple chemical vapor deposition method. These results confirm the feasibility of utilizing planar [BO3] units to optimize birefringence of borosulfates, and also open up broad prospects for UV NLO crystals in boron‐rich borosulfates.

Achieving Short-Wavelength Phase-Matching Second Harmonic Generation in Boron-Rich Borosulfate with Planar [BO3 ] Units.

Ultraviolet (UV) nonlinear optical (NLO) crystals which can produce short-wavelength lasers via a direct second harmonic generation (SHG) process are of great importance in modern laser technology. Currently, the exploration of UV NLO crystals in borosulfates is nearly stagnant since the non-phase matching (PM) property lies on the small birefringence induced by the intrinsically small optical anisotropy of the tetrahedral groups. Herein, for the first time, the planar [BO3 ] units were introduced into borosulfates leading to a boron-rich borosulfate (NH4 )2 B4 SO10 with unprecedented [B4 SO10 ]∞ layers and evidently enhanced birefringence. To the best of our knowledge, it achieves the shortest SHG PM wavelength of 252 nm in all reported borosulfates with deep UV cutoff edge (184 nm), large SHG response (1.1×KDP at 1064 nm and 0.15×β-BBO at 532 nm) and large birefringence (0.053 at 1064 nm) and is easy to grow single crystals via simple chemical vapor deposition method. These results confirm the feasibility of utilizing planar [BO3 ] units to optimize birefringence of borosulfates, and also open up broad prospects for UV NLO crystals in boron-rich borosulfates.

Noncentrosymmetric chalcohalide K2Ba3Ge3S9Cl2: A new nonlinear optical material with remarkable laser-induced damage threshold

Chalcohalides are attractive infrared (IR) nonlinear optical (NLO) materials because they can take advantages of the large second-harmonic generation (SHG) responses of chalcogenides and high laser-induced damage thresholds (LIDTs) of halides simultaneously, which are two correlated while contradictory indicators of the NLO performance. Here, a new chalcohalide, K2Ba3Ge3S9Cl2, was synthesized by a high temperature solid-state reaction, and it crystallizes in the polar noncentrosymmetric space group P63. The fundamental structural unit [Ge3S9]6– rings formed by three corner-sharing [GeS4]4– tetrahedra construct the framework, which further connects with {[KS3Cl]6–}∞ chains to build up the structure with Ba and K/Ba cations occupying the cavities. It exhibits a widest band gap of 3.69 eV among all Ba-based chalcohalides, and a high LIDT around 28.8 times that of AgGaS2. It exhibits a SHG intensity around 0.34 times that of AGS. These experimental results are verified by theoretical calculations on its electronic structure and optical properties.