Total electrical-to-optical power Efficiency of a Laser system.

The wall-plug efficiency of a laser System is its total electrical-to-optical power efficiency. Taking the term serious, the electrical power should be measured at the wall plug, SO that this efficiency includes losses in the power supply and also the power required for a cooling system, which can be quite significant for high power lasers. However, it is quite common that the wall-plug efficiency is calculated based on the electric power delivered to the laser diodes (e.g. in a diode-pumped Solid State Laser system), forgetting about the actual wall plug.