The diode or semiconductor laser

A diode, or semiconductor, laser operates in the near-infrared and into the visible region of the spectmm. Like the mby and Nd YAG lasers it is a solid state laser but the mechanism involved is quite different. 

Semiconductor lasers are some of the most efficient of all lasers, with an efficiency of abouf 30 per cenf. 

1 Bands in the solid state can be regarded as grossly delocalized orbitals extending throughout the sample. 

---