Light Amplification
The closer M2 values are to 1, the more laser energy is delivered to the laser spot. It allows for the processing of thicker materials, with deep wells that are thin.
Mirror galvanometers can be found in laser engravers. These mirrors move very fast to direct the laser's course. A simple rotation of 10 degrees at your head is sufficient to produce 1 1/2 inches of movement at ten inches. It is also used before engraving and cutting laser paths.