Yttrium orthovanadate (YVO4) is a crystal material used as a substrate in various optical and electronic applications. It is a crystalline solid with a high thermal stability, high refractive index, and low birefringence. This makes it a popular choice as a substrate for optical waveguides and filters. Additionally, its high dielectric constant and low dielectric loss make it an attractive choice for high-frequency and microwave applications. YVO4 is widely used as a substrate for optical parametric oscillators, laser frequency doubling, and nonlinear optical applications.