Neodymium-doped crystals are materials that have been infused with the element neodymium, a rare earth metal. These crystals are commonly used in lasers, where the neodymium ions help to amplify light. The most popular type of neodymium-doped crystal is neodymium-doped yttrium aluminum garnet (Nd:YAG), which is known for its efficiency and ability to produce high-quality laser beams. These crystals are utilized in various applications, including medical procedures, industrial cutting, and scientific research. The unique properties of neodymium-doped crystals allow them to emit specific wavelengths of light, making them valuable in fields such as optics and telecommunications.