How to make a laser pointer from scratch?

If you have entered the laser market, you may be familiar with the fact that lasers of a certain intensity or higher have the ability to burn. Use a laser pointer to light a match, break a balloon, cut electrical tape, etch certain types of wood, or light a fuse. However, it is the intensity of the laser, not the color of the beam, that determines the burning ability of a single laser. In fact, the color (or invisibility) of the beam does not affect the burning ability of the laser. Only the intensity of the laser can determine whether it is a burning laser. Generally, 200mW is the lowest starting point to break the black balloon. The higher the mW power, the greater the burning capacity (if more than 200mW). Generally, the crow drive laser pointer is 5-7 times brighter than other visible lasers, but has the same mW output power. For clarity, the brightness of a 100mW green laser is approximately 7 times that of a 100mW blue or violet laser. This is because green is the brightest color for the human eye, and generally the brightest color, which is one of the reasons why plants and chlorophyll produce green. Green is very obvious at night, in low light, fog or dusk (and laser color). The biggest difference is that it is very cost-effective, provides more visibility at a lower cost, and is more suitable for daytime use.