Yttrium Orthoaluminate (YALO3 or YAP) is a crystal substrate material used in various optical, electronic and photonic applications. Yttrium Aluminum Oxide (YAP) is a transparent crystal with a wide band gap, making it suitable for applications in the near-infrared (NIR) region. It has high thermal stability and a low thermal expansion coefficient, which makes it an ideal material for high-power laser applications and optical components. YALO3 is also used as a substrate for a range of thin film applications, such as waveguides, filters, and cavity resonators.