OST Photonics offers various functional crystal materials for laser systems, optical equipment and instruments. Crystals are divided into six types according to their functions: laser crystals (diffusion bonding crystals, Nd:YAG, Er:YAG, Yb:YAG, CTH:YAG, Nd:Ce:YAG, Nd:YVO4, Nd:GdVO4, Nd:YLF, Pr:YLF, Ho:YLF, Tm:YLF, Ti:Sapphire, Er:Yb: Glass), nonlinear crystals (KDP & DKDP), KTP, LiNbO3, LBO, BBO, BIBO), passive Q-switch crystals (Cr4+:YAG, Co2+:MgAl2O4), birefringent crystals (YVO4, �±-BBO), Magneto-optic Crystals (TGG) and optical crystals (BaF2, CaF2, MgF2, LiF, Germanium single crystal, Sapphire (Al2O3), YAG, ZnSe, Silicon single crystal, ZnS). If you want to know more about our functional crystals, please do not hesitate to contact OST Photonics. What are Functional Crystals? A wide range of functional crystal materials is used in various optical applications. While optical glass is commonly used as a transparent material, different functional crystal materials, primarily monocrystalline materials, are required for diverse applications due to their unique functionalities: In contrast to glass, birefringent crystals can exhibit birefringence, which is a requirement for various types of polarizers, wave plates, birefringent tuners, and other optical components. Commonly used birefringent crystal materials include YVO4, �±-BBO, quartz, calcite and sapphire. The lattice symmetry of a crystal material is not too high (such as a triangular, quadrilateral, or single prism), and it can exhibit nonlinearity. Nonlinear crystals are primarily used for nonlinear frequency conversion but also find applications in optical modulators like the Pokel cell. A wide variety of functional crystal materials can be used as laser crystals, serving as host materials for laser-active dopants (rare earth ions or transition metal ions). They typically exhibit relatively high transition cross sections, small gain bandwidth, and good heat conduction compared to laser-active glasses. In general, they also allow for higher doping concentrations. In some cases, functional crystal materials are used in spectral regions where glass does not have a wide enough wavelength range and high transmittance. In particular, various materials such as zinc sulfide (ZnS), zinc selenide (ZnSe) and Sapphire (Al2O3) are used as infrared crystals, and other materials such as lithium fluoride (LiF), calcium fluoride (CaF2) and magnesium fluoride (MgF2) are used as ultraviolet crystals. Some functional crystal materials, such as terbium gallium garnet (TGG), exhibit the Faraday effect (polarization rotation caused by magnetic fields), and they can be utilized in devices like Faraday rotators and Faraday isolators.