It will depend on the type of laser used. There are two primary types: the crystal rod laser and the solid-state laser. The latter generates light in an Nd YAG laser cavity. Around an Nd-doped yttrium silica glass crystal, specific LEDs are mounted. These LEDs stimulate the Nd dopant present in the crystal to emit radiation. However, the excess heat energy produced by this process must be cooled down, resulting in an energy deficit. This type of laser has a maximum energy efficiency of 27%, which is relatively low. On the other hand, the fibre laser generates light that stays inside a glass fibre, with no mirrors, outcoupling or fibre coupling. These lasers have energy rates of 40% and are increasing yearly, resulting in highly compact laser systems.