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In the past decades, the Tb3Ga5O12 crystal has been market-dominating for visible–near-infrared Faraday applications. However, its relatively low Verdet constant as well as heavy volatilization of Ga2O3 during growth makes it challenging to meet the continuous development of advanced lasers. In this work, a novel Tb3Al3Ga2O12 crystal is designed and studied for the first time. We demonstrated that the Tb3Al3Ga2O12 crystal possesses a better visible transparency, a higher thermal conductivity, and a larger Verdet constant compared with the Tb3Ga5O12 crystal. Moreover, due to the great reduction of Ga content, it is more capable of fabricating large-size low-cost single crystals. Hence, Tb3Al3Ga2O12 is an extremely potential material for Faraday applications in the visible–near-infrared range.

have been successfully commercialized. Unfortunately, these crystals are hindered for further extensive applications due to their inherent drawbacks, such as low laser damage threshold (34 MW cm -2 and 13 MW cm -2 for AgGaS 2 and AgGaSe 2 , respectively) [5] and severe optical absorption for ZnGeP 2 . In addition, nonoxide crystals such as CdGeAs 2 , LiInS 2 and CdSiP 2 are commonly grown by Bridgman method. [6] The growth process of Bridgman method cannot be observed and adjusted in real time because of the closed system, making it challenging to obtain large-size single crystals with high optical quality. Unlike chalcogenides and pnictides, oxide NLO crystals usually have wide band gap and large laser damage threshold, which are important for NLO materials. [7] Meanwhile, oxide crystals possess good growth habits and excellent physical properties, which is very beneficial to large-scale commercialization. However, considering the absorption of high-frequency phonons or their overtones from light atoms, most of the oxide crystals are difficult to completely cover the 3-5 µm atmospheric window. Therefore, it is urgent to develop novel mid-IR NLO materials with wider transmission range, larger nonlinear coefficient, and higher laser damage threshold.High-performance ferroelectric crystals are some of the important and widely used functional materials in optical fields, owing to their excellent electro-optical, acousto-optical, and second-order NLO properties. [8] For example, LiNbO 3 crystal has been considered as one of the most commercial crystals for applications in nonlinear optics owing to the extraordinary properties, such as large NLO coefficients, moderate birefringence, phase-matchability, and high crystal quality. [9] However, because of the high-density light scattering domains existing in most high-performance ferroelectrics crystals, the realization of transparent ferroelectrics crystals with giant second-harmonic generation (SHG) has long been a challenge. [10] Despite more decades of effort, ferroelectric crystals with high transparency and giant SHG have been difficult to realize. Until 2020, Qiu et al. obtained transparent Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PMN-PT) single crystal by applying alternating current to engineer the domain structures. [8b] This crystal exhibits a good transparency, a high piezoelectric coefficient, and a large electro-optical Environment-friendly lead-free potassium-sodium niobate (KNN) has become one of the most extensively investigated ferroelectrics in the past decade, while high transparency KNN single crystal has never been realized yet. Here, a transparent KNN single crystal is successfully grown by the top seeded solution growth method. The KNN crystal possesses a very wide transmittance range of 0.37-8 µm, completely covering the important mid-infrared atmospheric transparent window (3-5 µm). Noticeably, the KNN crystal exhibits the largest second-harmonic generation efficiency (7.6× that of potassium-titanyl phosphate (KTP)) with type-I phase matchability unde...

The selenite and tellurite compounds have garnered plenty of attention in both fundamental and applied chemistry. Se4+ and Te4+ cations possess lone pair electrons, which changes coordination environments and performance...