Solid-state lasers are a type of laser that use a solid material as the gain medium to produce light. This gain medium is typically a crystal or glass that is doped with ions, such as neodymium or yttrium aluminum garnet (YAG). When energy is supplied to the medium, it excites the ions, allowing them to emit coherent light when they return to their original state. These lasers are known for their efficiency and durability, making them suitable for various applications, including medical procedures, industrial cutting, and scientific research. Solid-state lasers can produce high-quality beams and are often used in devices like laser pointers and laser engraving machines.