high power diode lasers

A laser diode is a laser where the active medium is a semiconductor similar to that found in a light-emitting diode. The most common and practical type of laser diode is formed from a p-n junction and powered by injected electrical current. These devices are sometimes referred to as injection laser diodes to distinguish them from optically pumped laser diodes, which are more easily produced in the laboratory.

Principle of operation

A laser diode, like many other semiconductor devices, is formed by doping a very thin layer on the surface of a crystal wafer. The crystal is doped to produce an n-type region and a p-type region, one above the other, resulting in a p-n junction, or diode.

As in other diodes, when this structure is forward biased, holes from the p-region are injected into the n-region, where electrons are the dominant carrier. Similarly, electrons from the n-region are injected into the p-region, where holes are common. When an electron and a hole are present in the same region, they may recombine by spontaneous emission—that is, the electron may re-occupy the energy state of the hole, emitting a photon with energy equal to the difference between the electron and hole states involved. High Power Devices Inc.