The types of lasers can be divided into: gas lasers, liquid lasers, solid lasers, and semiconductor lasers. Strictly speaking, semiconductor lasers are also a kind of solid-state lasers, but due to the large amount of commercial semiconductor lasers currently used, for example, optical reading. Head, optical communication light source, laser pointer, etc., so the laser has profoundly affected our lives, and laser diodes can be divided into edge-emitting lasers and surface-emitting lasers.
The four types of lasers described above, only the semiconductor laser has the smallest volume and the lowest cost, and can be used only with a small battery, so it can be widely used in various electronic products.
Laser diodes are cylindrical in appearance and usually have different shapes depending on the package. However, the only part that really shines is the "die". The size of the chip is similar to that of a sand on the beach. It can emit very strong light. Because the chip of the laser diode is very small, a two-inch GaAs wafer can make thousands of chips, and then packaged after cutting. The manufacturing process of the laser diode is similar to that of the silicon wafer. It is made by using yellow light lithography, doping technology, etching technology, and film growth.
