Mesh EmittersThe ability for a surface to emit illumination usually described by a Black Body or Texture emission type. use geometry to emit light into a scene. This is made possible by applying a DiffuseAmount of diffusion, or the reflection of light photons at different angles from an uneven or granular surface. Used for dull, non-reflecting materials or mesh emitters. MaterialThe representation of the surface or volume properties of an object. to the surface, then connecting an Emission node to the material's Emission channel.
Emission nodes can be accessed from Create Nodes > New Emission.