This is an interesting question, often unanswerable. With the rapid development of aviation technology, satellite technology, and military technology worldwide, laser pointer technology, such as the development of daily lasers such as DVD players and even high-power handheld lasers; this is an important scientific issue that we can consider. The term "laser" is a scientific abbreviation, which stands for "light amplification by the excitation light of light radiation", we usually call them lasers.
Researchers at Bell Labs published the theory for producing laser light in 1958. The first laser was manufactured at Hughes Aircraft Corporation in 1960. It used a ruby as the laser medium, light as an energy source, and a mirror to make a resonator. The semiconductor laser was invented in 1962. It uses a semiconductor material similar to that used in transistors and integrated circuits used in laser engraver media. It also uses direct current (DC) generated by the battery as an energy source. It still uses resonant mirrors. The first semiconductor lasers produced invisible infrared radiation. Current semiconductor lasers can also produce visible light, among which red is the cheapest type of semiconductor laser, while green, blue and violet are becoming more and more expensive. The semiconductor lasers used in laser pointers are also called diode lasers because they are a type of semiconductor diode. Diodes can easily pass current in one direction; when current passes, light-emitting diodes and laser diodes emit light. Since the late 1950s, the production cost of semiconductor electronic products has been reduced. They also become smaller and require less energy. They became cheap enough to be used in consumer electronics such as laser pointers in the 1980s. Current laser diodes are the size of blood cells.
Compared with resonant cavities, the light they produce is less collimated (moving in one direction) than most lasers. Therefore, they need some kind of external optics (lens) to focus the light into a tighter beam. Like many semiconductor devices, laser diodes are very precise and need to be protected from the environment and surges. The power control circuit usually includes a photodiode (a diode that generates electricity when light is irradiated) to monitor the output of the blue laser pointer diode to prevent the diode from receiving too much or too little power. The diode is protected from the environment by a plastic case, so it is similar to most other semiconductor devices used on circuit boards.