The working principle of the semiconductor laser is an excitation mode. Semiconductor materials (both electrons) are used to transition between energy bands, and two parallel mirror surfaces are formed as the mirrors by using the cleavage surface of the semiconductor crystal to form a resonant cavity to enable optical oscillation and feedback. Generated light radiation amplification, output laser.

Characteristics of semiconductor lasers: The advantages of semiconductor lasers are their small size, light weight, reliable operation, low power consumption, and high efficiency.

A semiconductor laser is a device that generates stimulated emission by using a certain semiconductor material as a working substance. The principle of operation is to achieve a non-equilibrium load between the energy bands (conductor bands and valence bands) of semiconducting materials, or between the energy bands of semiconducting materials and the level of impurities (acceptor or donor) through a certain excitation method. The inversion of the number of protons in the stream, when a large number of electrons in the population inversion state recombine with the holes, stimulates the emission.

There are mainly three kinds of semiconductor laser excitation methods, namely, electro-injection, optical pump and high-energy electron beam excitation. Electro-injection semiconductor lasers, generally by GaAS (InGaAs), InAS (InGaAs), Insb Semiconductor junction diodes made of materials such as Indium-Iron (Indium), which are excited by forward biased injection currents, produce stimulated emissions in the junction plane region. Optical pump type semiconductor lasers generally use N-type or P-type semiconductor single crystals (such as GaAS, InAs, InSb, etc.) as working substances, and lasers emitted from other lasers as optical pump excitations. High-energy electron beam excitation type semiconductor lasers are also generally used. The N-type or P-type semiconductor single crystal (such as PbS, CdS, ZhO, etc.) is used as a working substance and is excited by externally injected high-energy electron beams. Among the semiconductor laser devices, the current performance is good, and the widely used is an electrically-injected GaAs diode laser having a double heterostructure.