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Metal chalcogenophosphates are receiving increasing interest, specifically as promising infrared nonlinear optical (NLO) candidates. Here, a rare‐earth chalcogenophosphate Eu2P2S6 crystallizing in the monoclinic noncentrosymmetric space group Pn was synthesized using a high‐temperature solid‐state method. Its structure features isolated [P2S6]4− dimer, and two types of EuS8 bicapped triangular prisms. Eu2P2S6 exhibits a phase‐matchable second‐harmonic generation (SHG) response ≈0.9×AgGaS2@2.1 μm, and high laser‐induced damage threshold of 3.4×AgGaS2, representing the first rare‐earth NLO chalcogenophosphate. The theoretical calculation result suggests that the SHG response is ascribed to the synergetic contribution of [P2S6]4− dimers and EuS8 bicapped triangular prisms. This work provides not only a promising high‐performance infrared NLO material, but also opens the avenue for exploring rare‐earth chalcogenophosphates as potential IR NLO materials. [ABSTRACT FROM AUTHOR]

Non‐linear optical chalcogenides with a wide band gap (Eg) and excellent NLO properties are key materials for highly desirable multiwaveband tunable optical parametric oscillators (OPOs). We exploit the "electronic structure engineer bucket effect" to develop a novel dual‐waveband SrZnGeS4 with an ultrawide transparency window. It exhibits an asymmetric Fdd2 structure that consists of layers formed by corner‐sharing [ZnGeS6] dimers. SrZnGeS4 is transparent from 0.30 to 23.6 μm, spanning the UV‐, vis‐, mid‐ and far‐IR spectral regions and has the widest Eg (3.63 eV) in the AeMIIMIVQ4 family to date. It exhibits phase matching, high SHG intensities (e.g. 11.0×KDP and 17.5×AGS under λinc=1450 and 950 nm, respectively), and a very high laser‐induced damage threshold (35×AGS). These results not only suggest bright prospects for high‐power laser applications but may also enable applications of the multiwaveband OPO system from the UV‐visible to far‐IR regions. [ABSTRACT FROM AUTHOR]

The essence of rational design syntheses of functional inorganic materials lies in understanding and control of crystal structures that determine the physical properties. AgGaS2 has the highest figure of merit for IR nonlinear optical interactions to date, but suffers low laser‐induced damage threshold (LIDT). The partial Li substitution of Ag atoms is now shown to push up the bottom of the conduction band and flatten the top of the valence band, leading to an ultrawide band gap of 3.40 eV (record high for AgGaS2, indicating a transparency edging nearly 180 nm shorter than that of AgGaS2), which gives Li0.60Ag0.40GaS2 a LIDT 8.6 times stronger when AgGaS2 is compared. Li0.60Ag0.40GaS2 exhibits 1.1 times stronger nonlinear susceptibility, which is because the energy‐favorable Li substitution gradually decreases the sulfur dislocation in the lattice, which allows a better geometric superposition of nonlinear optical tensors. [ABSTRACT FROM AUTHOR]

The essence of rational design syntheses of functional inorganic materials lies in understanding and control of crystal structures that determine the physical properties. AgGaS2 has the highest figure of merit for IR nonlinear optical interactions to date, but suffers low laser‐induced damage threshold (LIDT). The partial Li substitution of Ag atoms is now shown to push up the bottom of the conduction band and flatten the top of the valence band, leading to an ultrawide band gap of 3.40 eV (record high for AgGaS2, indicating a transparency edging nearly 180 nm shorter than that of AgGaS2), which gives Li0.60Ag0.40GaS2 a LIDT 8.6 times stronger when AgGaS2 is compared. Li0.60Ag0.40GaS2 exhibits 1.1 times stronger nonlinear susceptibility, which is because the energy‐favorable Li substitution gradually decreases the sulfur dislocation in the lattice, which allows a better geometric superposition of nonlinear optical tensors. [ABSTRACT FROM AUTHOR]

Metal chalcogenophosphates are receiving increasing interest, specifically as promising infrared nonlinear optical (NLO) candidates. Here, a rare‐earth chalcogenophosphate Eu2P2S6 crystallizing in the monoclinic noncentrosymmetric space group Pn was synthesized using a high‐temperature solid‐state method. Its structure features isolated [P2S6]4− dimer, and two types of EuS8 bicapped triangular prisms. Eu2P2S6 exhibits a phase‐matchable second‐harmonic generation (SHG) response ≈0.9×AgGaS2@2.1 μm, and high laser‐induced damage threshold of 3.4×AgGaS2, representing the first rare‐earth NLO chalcogenophosphate. The theoretical calculation result suggests that the SHG response is ascribed to the synergetic contribution of [P2S6]4− dimers and EuS8 bicapped triangular prisms. This work provides not only a promising high‐performance infrared NLO material, but also opens the avenue for exploring rare‐earth chalcogenophosphates as potential IR NLO materials. [ABSTRACT FROM AUTHOR]