In addition, compared to other types of lasers, laser diodes use very little power. Overall efficiencies greater than 30% are typical in the case of. Laser diodes are electrically pumped semiconductor lasers in which the gain is generated by an electric current flowing through a p–n junction or (more frequently) a p–i–n structure. In such a heterostructure of a bipolar interband laser, electrons and holes can recombine, releasing the energy. The optical power value, Po, is the most basic characteristic of a laser diode. The most common devices are in the range of 808nm through 980nm. These gadgets track down wide applications because of their proficiency and minimal size.