What type of laser medium can be solid state?

The choice of ND:YAG as a solid-state laser medium is correct because it consists of a crystal or glass host material that is doped with neodymium ions. This doping process allows the laser to efficiently convert electrical or optical energy into laser light. In solid-state lasers, the laser medium is solid at room temperature, which is a fundamental characteristic that differs from gas or dye lasers.

Carbon Dioxide and Helium Neon lasers are examples of gas lasing mediums, where the gain medium consists of gas mixtures. These types of lasers typically operate at different physical principles and require different operational setups compared to solid-state lasers.

Dye lasers, while being effective and versatile, utilize organic dye as the lasing medium, which is usually in a liquid state rather than a solid one. Thus, they do not fall into the category of solid-state lasers.

The unique properties and benefits of solid-state lasers like ND:YAG make them widely utilized in various applications, including medical fields, industrial cutting, and laser marking.